Arctic Sea Ice : Forum

AGW in general => Consequences => Topic started by: Tony Mcleod on February 19, 2017, 01:47:43 AM

Title: Ice-free Arctic
Post by: Tony Mcleod on February 19, 2017, 01:47:43 AM
The phrase "Ice-free Arctic" has long been used by those sceptical of mainstream GW science as a confected weapon to mock and sow doubt. It will be used again.

Lurking on denier sites( :o ::)) reveals what gets them really excited and what they, in turn, like to twist and ampilfy back. For example, over at WUWT there is a mocking meme that 1 million sqkm = 1 Wadham.

I see how important is to clearly state the prediction (of an 'Ice-free' Arctic) to leave as little wiggle room as possible for misunderstanding or manipulation.

magnamentis has talked bout this here https://forum.arctic-sea-ice.net/index.php?action=post;quote=103624;topic=1846.100;last_msg=103721

and elsewhere.

Not sure how you give a warning about "ice-free" conditions while there is a million square kms of the stuff and not have that mocked or twisted. But I think the discussion is an important one because I just know that, in October this year, there will be another intense, semantic 'debate' about it in the media. And like so many other zombies talking points it will be used, incredibly to me, as evidence we can't trust the science/data, blah, blah, blah... in the coming years.

Unfortunately it needs to taken into account when discussing this subject, because more than any other, it may prove to be pivotal in minds of the general public and for any outcomes that may be acheived.

You'd think a huge area with no ice suddenly appearing would be the wake-up call that galvanises the species... but it probably won't be as simple as that.

So how to express 'ice-free' and have it be patently true?
 
Title: Re: Ice-free Arctic
Post by: Pmt111500 on February 19, 2017, 02:19:14 AM
oo, who gets a unit named after them these days?  But yeah, they're patently silly and stupendously stupid down there. They start to talk about the ice in the clouds soon after the pole is open, I guess.
Title: Re: Ice-free Arctic
Post by: Archimid on February 19, 2017, 02:36:52 AM
From the point of view of someone  honorable it would seem  that if you have the perfect argument people won't  be able to pick at it. But to dishonorable people, there is no such thing as a perfect argument.  They will appeal not  to the logic of the argument but to the logical fallacies that appeal to people.

I think scientist should have no political consideration for their arguments. They should stride for the best possible truth they can. If that means predicting the end of the world and failing, then so be it.



Title: Re: Ice-free Arctic
Post by: Pmt111500 on February 19, 2017, 03:06:25 AM
The ship visiting north pole next summer should have a buoy with only a pole in it. Some gyroscopic 'tricks' could be used to keep it stable. We ain't havin' some wobbly axises!
Title: Re: Ice-free Arctic
Post by: oren on February 19, 2017, 07:02:43 AM
There's no way past the deniers, so I wouldn't bother too much. And for the general public (if any still exist out there) it should be clarified as part of the publication - ice free meaning less than 1 m km2 in September compared to x km2 on the same date 30 years ago.
Title: Re: Ice-free Arctic
Post by: Tony Mcleod on February 19, 2017, 07:48:17 AM
There's no way past the deniers

Probably right about that - the stronger the evidence the sneakier the scientinst.

I have shut a few of them down with Wipneus' Global Ice graph. Their first reaction:
'there must be something wrong with the satellite". When shown that's not the case they quietly slink away. Lord Monckton amongst them.

They don't like the look of the FDD graphs either.
Title: Re: Ice-free Arctic
Post by: Neven on February 19, 2017, 10:24:39 AM
For example, over at WUWT there is a mocking meme that 1 million sqkm = 1 Wadham.
That's actually quite funny!  :D

---

I've always liked Walt Meier's definition:

Quote
“Instead of simply saying “ice-free”, my view is that it should be described as “ice-free for all practical purposes”. To me this means: seeing blue instead of white throughout the Arctic Ocean (except along the coasts), allowing ships to operate within the Arctic Ocean with little chance of seeing substantial ice, having a significant effect on the Arctic ecosystem, and having a significant effect on Arctic. (The last two are likely already occurring.)
[...]
So I’m not worried too much about what we mean by “ice-free” or what specific number we put on it – that’s for gamblers placing bets to quibble about.”
I also like what I've said myself in a blog post last year called Consensus and consequences (http://neven1.typepad.com/blog/2016/03/consensus-and-consequences.html):

Quote
Discussing the exact definition of ice-free may itself become a smoke screen that shrouds a more important issue, and thus cause even more confusion. Fortunately, the authors seem to be aware of this when they state in their paper's final paragraph:

Many of the impacts of decreasing ice cover will be felt irrespective of the precise date when the Arctic is declared seasonally ice-free.

I've said it before, and I'll say it again: An ice-free Arctic isn't some starting shot after which the consequences of Arctic sea ice loss spring into action. They already did so a while ago, but we're just not seeing it clearly as the signal hasn't crossed the bounds of natural variability for long enough yet.
Title: Re: Ice-free Arctic
Post by: Meirion on February 19, 2017, 10:49:13 AM
From a media point of view the day you can fly from Svalbard to the North Pole circle it and fly back without seeing any ice sheet will be the day that wakes up the world. It won't be an ice-free Arctic but it will be an ice-free North Pole.

 
Title: Re: Ice-free Arctic
Post by: anthropocene on February 19, 2017, 11:08:29 AM
There is an interesting discussion going on other thread(s) about the disappearance of the temperature inversion and the impact this will have on the ice. It is becoming more and more clear that the temperature inversion is a feedback mechanism which makes a large contribution to the ice covering at the North Pole being in a stable state. There have been similar points made (mainly by Lodger) about the cold water lens.
When these two feedbacks are gone then the system will jump to an ice-free state and it will be very difficult for large quantities of ice to be generated during the winter months. This can be summarised by saying the Arctic will move from an ice/land climate to an oceanic climate.
A lot of people seem to think that in the future the Arctic will be "ice-free" briefly at minimum in September and then in subsequent years the length of the "ice-free" period will gradually increase. I now tend to think that once the contiguous area of ice decreases below the value that the above feedbacks don't have any significant impact then the Arctic will be "ice-free" for a long time each year. That is,  when it is passed this tipping point  in one year the Arctic will switch to being ice-free for several months.
Therefore from a scientific point of view I suggest the definition of "ice-free" should be the area at which this tipping point occurs. I've no idea what the value is but I suspect it is less than 1 Wadham (which is approximately a circle of radius 600km which (if contiguous and solid) I would guess would be able to maintain its own climate).
Title: Re: Ice-free Arctic
Post by: Tony Mcleod on February 19, 2017, 01:35:31 PM
anthropocene
"This can be summarised by saying the Arctic will move from an ice/land climate to an oceanic climate."

Or when its been geo-engineered from being a frozen desert into a temperate ocean.
Title: Re: Ice-free Arctic
Post by: Jim Williams on February 19, 2017, 03:15:40 PM
In a previous conversation I proposed that the Arctic Ocean (if not necessarily all the bays) would be ice free when there was no longer enough ice to keep the air from getting warm.  After some diddling, the notion that seemed about right was for DMI 80N to be above 5C (or was it 3C?) for 10 or more days in a row.

Basically, when my soda starts getting warm it doesn't matter if there are still a few flecks of ice in the glass.
Title: Re: Ice-free Arctic
Post by: Tony Mcleod on February 20, 2017, 04:15:55 AM
I like your idea Meirio, the bottom line is it needs to be a '(tabloid) media view'. A map of the journey and a photo of a blue-water pole would be very persausive meme. The headline: A farewell to ice is spoit by having ice in the picture, even if there is a boat moored alongside.
Title: Re: Ice-free Arctic
Post by: Cid_Yama on February 20, 2017, 05:08:07 PM
Too many people concerned with what the deniers will say or the masses will think.

We hit 1 million sq km, it is an extinction level event.  Temperatures over much of the Earth will exceed that at which warm blooded creatures can survive.(7C+ above pre-industrial)  Even a few hours of such temperatures will make a place uninhabitable.

Livestock die-off and global crop failures will crash delivery systems.  Famine, pandemics from weakened immune systems, surface water depletion, massive displacement of refugees, war over what's left, you won't be worrying about what the morons think.   
Title: Re: Ice-free Arctic
Post by: Zantage on February 20, 2017, 06:57:10 PM
How about qualifying ice-free in the term itself: "Essentially Ice Free" (EIF)? While the term still requires definition, it would be more difficult for deniers to abuse it, requiring a discussion of the meaning of "essentially." We could even hope (undoubtedly forlornly) for constructive engagement over its use.
Title: Re: Ice-free Arctic
Post by: Shared Humanity on February 20, 2017, 07:08:43 PM
Too many people concerned with what the deniers will say or the masses will think.

We hit 1 million sq km, it is an extinction level event.  Temperatures over much of the Earth will exceed that at which warm blooded creatures can survive.(7C+ above pre-industrial)  Even a few hours of such temperatures will make a place uninhabitable.

Livestock die-off and global crop failures will crash delivery systems.  Famine, pandemics from weakened immune systems, surface water depletion, massive displacement of refugees, war over what's left, you won't be worrying about what the morons think.   

A gross exaggeration. The ice reduction is a continuum and 1 million sq km is on this continuum, different than 3 million sq km but still connected. I have no doubt we are heading towards such an event for many if not most of us with BAU but it will hardly occur when we hit 1 million sq km. This thread has quickly devolved into a strange conglomeration, more smoke than light whereas the topic of an ice free Arctic has a lot of possibilities.
Title: Re: Ice-free Arctic
Post by: Michael J on February 20, 2017, 11:54:03 PM
You will never convince the deniers - but I think that presenting good factual science will chip away at the undecided. Eventually the politicians who deny climate change will either get voted out or "see" the light.
Title: Re: Ice-free Arctic
Post by: Cid_Yama on February 21, 2017, 03:53:20 AM
Too many people concerned with what the deniers will say or the masses will think.

We hit 1 million sq km, it is an extinction level event.  Temperatures over much of the Earth will exceed that at which warm blooded creatures can survive.(7C+ above pre-industrial)  Even a few hours of such temperatures will make a place uninhabitable.

Livestock die-off and global crop failures will crash delivery systems.  Famine, pandemics from weakened immune systems, surface water depletion, massive displacement of refugees, war over what's left, you won't be worrying about what the morons think.   

A gross exaggeration. The ice reduction is a continuum and 1 million sq km is on this continuum, different than 3 million sq km but still connected. I have no doubt we are heading towards such an event for many if not most of us with BAU but it will hardly occur when we hit 1 million sq km.

Many people have a hard time grasping the concept of Abrupt Climate Change.  We seem to be wired to expect linear change.

Hard to reply without knowing what you are referring to when you say gross exaggeration.

Limits of Human Adaptability
Quote
It seems to be widely assumed that humans can adapt to any amount of warming, on the basis that humans live in such a wide variety of climates now. We show that when examined in terms of the peak value of the wet-bulb temperature (Tw), which ultimately governs the possibility of transfer of metabolic heat to the environment, the worlds present-day climates are far less variable than one might think based on mean temperature. A warming of only a few degrees will cause large parts of the globe to experience peak Tw values that never occur today; 7C would begin to create zones of uninhabitability due to unsurvivable peak heat stresses (periods when the shedding of metabolic heat is thermodynamically impossible); and 10C would expand such zones far enough to encompass a majority of today's population. It is unknown how much of our present 7- 10C cushion we can live without before experiencing significant problems, making it difficult to draw conclusions about more modest climate changes, but the limits themselves rest squarely on basic thermodynamics.
http://www.pnas.org/content/107/21/9552.full (http://www.pnas.org/content/107/21/9552.full)


Quote
"So in a matter of 1 to 2 years, there's a very large change out over the ocean, and as a I said, the only thing we can think of that happens that fast is a change in the sea ice extent ..."
Abrupt Climate Change - Jim White at 2014 AGU conference (https://www.youtube.com/watch?v=siWCXOypJh4)





Title: Re: Ice-free Arctic
Post by: Gray-Wolf on February 21, 2017, 11:17:09 AM
Thanks for the bottom link Cid-Tama!

Talk of North Greenland seeing an abrupt change of 10 to 15 degrees reminds me of some of the excursions in temp we have seen this last 2 years across the basin to the pole.

Are we now within the period of rapid change across the basin that will see another hike in N.Greenland temps over a short period, a temp hike that will establish and not be a fleeting forcing?
Title: Re: Ice-free Arctic
Post by: magnamentis on February 21, 2017, 02:38:26 PM
Too many people concerned with what the deniers will say or the masses will think.

i think i know how you mean it but the way you say it it's missing an important point. some of the reasons why humans as a whole don't change their habits fast enough to make a timely change are:

a) that deniers feed them with welcome fake news that fits their needs to continue the old, ego-centred lazy path.

b) too many people don't care and/or fall for "a)" and hence continue their destructive path

hence it indeed matters, basically ONLY matters what the masses think and in that context what the deniers say
if we, who do NOT DENY and who are willing to adapt and make changes in our lives can spread the news fast enough and have a chance to see for changes in a timely manner.

i hope it's clear that this post is not meant like who is right or not but giving some input to consider as to whether we should care about the masses or not. about the hard core deniers we can do little because they deny for interests like power and money and belonging to their chosen group more than due to genuine ignorance. i believe that most of the famous and influencing hard-core deniers speak out against better knowledge, similar to ancient popes who had children and fu...ed around while preaching abstinence and chastity.
Title: Re: Ice-free Arctic
Post by: Shared Humanity on February 21, 2017, 02:47:55 PM

Many people have a hard time grasping the concept of Abrupt Climate Change.  We seem to be wired to expect linear change.

Hard to reply without knowing what you are referring to when you say gross exaggeration.


I have no difficulty grasping abrupt climate change and it will take far less than a 7C increase in global temperature to destroy human civilization, my guess is 3C will do the trick. At 3C large areas of the planet will be rendered uninhabitable by human beings or any other large mammals. I believe that BAU is putting us on the path to an extinction level event although pockets of humanity will likely survive in niche environments due to our adaptability.

What was stated that is a gross exaggeration is that having Arctic ice drop to 1 million Sq km would cause a 7C rise in temperatures and an extinction level event. It serves no purpose to say such garbage and, in doing so, you provide ammunition to global warming deniers.

My biggest objection to your comment is that it does not belong on this thread which is about an Ice Free Arctic. If you scan the comments on the thread, they were focused on the definition of Ice Free and its implications. There are appropriate threads for your comments and they would serve to contribute to discussions that are already taking place. I think the consequences section of this wonderful blog has several threads where these ideas are being discussed.

http://forum.arctic-sea-ice.net/index.php/board,1.0.html (http://forum.arctic-sea-ice.net/index.php/board,1.0.html)

Title: Re: Ice-free Arctic
Post by: Shared Humanity on February 21, 2017, 03:11:33 PM
How about qualifying ice-free in the term itself: "Essentially Ice Free" (EIF)? While the term still requires definition, it would be more difficult for deniers to abuse it, requiring a discussion of the meaning of "essentially." We could even hope (undoubtedly forlornly) for constructive engagement over its use.

I like the idea of EIF. With the trend towards increased dispersion at minimum and the ongoing reduction of ice at minimum as well, we are very close to having SIE drop to 1 million sq km. This will be due, in part, to the 15% threshold for extent. You will still be able to boat around and encounter widely dispersed rubble floating in areas that are below 15%. We may want to define EIF by picking a percentage of the remaining ice that just barely contributes to extent, say 15% to 20% concentration. When this category of ice makes up say 50% of total remaining extent (Picked at random, I don't know what this should be), the Arctic can be declared EIF.
Title: Re: Ice-free Arctic
Post by: Shared Humanity on February 21, 2017, 03:33:01 PM
The more I think about EIF, the more I like the idea. Thank you for the suggestion. Here's another possible way of measuring this.

Large areas of our Granddad's Arctic could not be navigated except by ice breakers and, even then, there were areas they could not go. At what concentrations of this relatively thin, rotten ice does the Arctic become navigable by ordinary ships and large boats, perhaps the typical yacht owned by a 1%er. I would think 30% is navigable but I am not certain. We should pick a concentration in which the ordinary adventurous person would feel comfortable sailing and, when some fairly large percent of the remaining ice (perhaps 80% or 90%) falls below this threshold, we declare the ocean EIF.
Title: Re: Ice-free Arctic
Post by: gerontocrat on February 21, 2017, 03:56:58 PM
I have a speculation that the 15% rule for sea ice extent comes from when ships had sails and no engines. To sail into where sea ice was guessed at more than 15% coverage would be regarded as total folly. But 'tis but speculation - Google can't tell me ?

In a little yacht with their notoriously unreliable engines (and even more unreliable toilets) you would not get me near a sea with 30 % sea ice.
Title: Re: Ice-free Arctic
Post by: Pmt111500 on February 21, 2017, 05:20:11 PM
30% is usually not navigable for ordinary yachts as the ice moves around you may get in between floes. At least it's very slow going with constant watch and using poles to get them off boat, and this only in silent seas, on rougher seas the floes banging against the on-coming vessel are lethal for many hull materials. Imagine a 10ton small block of 25 cm ice hitting at 10 knots. 15% should be navigable but wouldn't go there either myself.
Title: Re: Ice-free Arctic
Post by: Dundee on February 21, 2017, 05:54:53 PM
For all the quibbling about what precisely an "ice free" minimum is or is not, I suspect when the switch flips it will be unmistakable. So far, "seasonally ice free" has been an incremental process - one does not have to look hard to find areas that now reliably melt out in the summer where once they did not. Rather than being locked in at the freezing point, SST's in these basins begin to rise after the ice is gone, and they cannot refreeze until that sensible heat is managed. This brings marked local changes, but to date the Arctic as a whole has been dying a death of a thousand cuts.

Arguably, there has already been a state change - rather than having an effect on only a narrow band of ice (the MIZ), waves/swells now arguably affect a large portion of Arctic sea ice. What we have now does not look or behave like the "ice pack" we learned about in elementary school. Even so, the impact of this remains complicated - things look different, but you can't really point to a large step change in the behavior of extent or volume.

I believe the real shift will occur when the refreeze, rather than working from the central ice pack out (as it has for as long as it matters), has to work from orphaned or land bound ice far from the pole back toward the center of the CAB. The most enduring cold in the Arctic (so far) has been in Greenland - unlikely to be ice free any time soon. Cold spots are also generated by jet stream waves -  it is easy to imagine them being stable enough to shelter significant remnant ice. Be that as it may, and no matter how much or how little remnant sea ice survives a season, growing a healthy ice pack from the margins (across waters, exposed to sunlight and un-buffered by ice, whose temperatures are well above freezing) will be a lot tougher than it would be if even a modest bit of ice survives deep in the CAB (damping motion in the water beneath it, holding SST's at its margins firmly at freezing, from which ice can begin growing just a few degrees below zero rather than the -10C typically required in open water to overcome heat transfer from depth, and divorced from the heat of the sun almost at the stroke of the equinox). It could happen in one season or over the course of several but once the pattern of Arctic Circle in replaces Pole out, everything will be different and going back will probably not happen until long after it will matter to us, our grandchildren, or their grandchildren.

I don't expect it will be amenable to a tidy number, but as the saying goes, I think we will know it when we see it. To mis-use another cliché, we won't have to look for an "ice free" September, it will come and find us.

(Off topic, but I am afraid that even though this shift will attract attention, it won't necessarily bring about action. There are an awful lot of people out there that believe 'global warming' means they won't have to move to Arizona after all, they won't need to replace their snow blower when it wears out, Canada will become an extension of the very productive Corn Belt, and Arctic oil and minerals will finally become accessible. Going down the list of talking points - it ain't happening - if it is happening, we didn't do it - why stop it from happening because it will be great! - and finally, but never uttered in public, even supposing what we are doing right now is making the really, really bad things inevitable if they won't actually happen until long after I retire from office, who cares? Right now, we have an election to win!)
Title: Re: Ice-free Arctic
Post by: Koop in VA on February 21, 2017, 06:10:29 PM
I think this is a good discussion to have but I think we also need contextualize the conversation.

The first time I learned that "ice free" did not mean zero ice was when I was trying to understand Maslowski's prediction of an ice free Arctic.  I think he made the prediction in 2007 and indicated that 2013 might be the year where we were "ice free".  I think his current prediction is "ice free" within 3 years of 2016.  Anyway, the point being I don't know if I fully understand whether Maslowski's definition of "ice free" is common within the sea ice community or if this was merely his definition.

The other context that I believe is important is to understand the broad consensus of when the Arctic is expected to be "ice free" and then to understand where Maslowski and others are on the spectrum of predictions.

For example, in this 2013 article, the author writes that most models predict an ice free Arctic by 2100.

http://www.montereycountyweekly.com/news/local_news/nps-researchers-predict-summer-arctic-ice-might-disappear-by-years/article_f0d1fc46-56dc-11e3-9766-001a4bcf6878.html (http://www.montereycountyweekly.com/news/local_news/nps-researchers-predict-summer-arctic-ice-might-disappear-by-years/article_f0d1fc46-56dc-11e3-9766-001a4bcf6878.html)

Anyway, yes, we can come up with an alternate way of expressing "ice free Arctic".  "Essentially ice free" basically works for me but if we went that route the "skeptic" community will eviscerate the change in language in much the way that they continue to hammer how "global warming" morphedinto "climate change".  Therefore, I would argue that while a new understanding of "ice free" needs to come about, the context behind the reason for the change and the context of the predictions for when "ice free" will occur is more important and will help the lay person better understand the ramifications of a blue Arctic.
Title: Re: Ice-free Arctic
Post by: Cid_Yama on February 21, 2017, 06:13:02 PM

Many people have a hard time grasping the concept of Abrupt Climate Change.  We seem to be wired to expect linear change.

Hard to reply without knowing what you are referring to when you say gross exaggeration.



Quote
What was stated that is a gross exaggeration is that having Arctic ice drop to 1 million Sq km would cause a 7C rise in temperatures and an extinction level event. It serves no purpose to say such garbage and, in doing so, you provide ammunition to global warming deniers.

My biggest objection to your comment is that it does not belong on this thread which is about an Ice Free Arctic.

In your opinion, which, since you provide no actual counter-argument, seems based on nothing but your feelings about it.

This IS about an ice free Arctic as a trigger to abrupt climate change.  Your feelings about it, not withstanding.

As stated I could give a rat's a** what the deniers have to say, or you for that matter.  We are way past being able to do anything about it.

A state change in the climate is imminent.  The changes in weather patterns, including rain tracks moving northward towards the poles, will profoundly impact global crop yields and surface water availability.   

And just what do you think will happen to the already mostly degraded subsea relic permafrost following a blue ocean event?

Quote
The ESAS is the largest shelf in the world, encompassing more than 2 million square kilometers, or 8 percent of the world's continental shelf. Shakhova believes it holds an area-weighted contribution to the global hydrate inventory of "at least 10 to 15 percent."

"These emissions are prone to be non-gradual (massive, abrupt) for a variety of reasons," she told Truthout. "The main reason is that the nature of major processes associated with methane releases from subsea permafrost is non-gradual."

This means that methane releases from decaying frozen hydrates could result in emission rates that "could change in order of magnitude in a matter of minutes," and that there would be nothing "smooth, gradual or controlled" about it; we could be looking at non-linear releases of methane in amounts that are difficult to fathom.

She explained that the transition from the methane being frozen in the permafrost, either on land or in the shallow northern shores of the East Siberian Arctic, "is not gradual. When it comes to phase transition, it appears to be a relatively short, jump-like transformation from one state of the process to another state. The difference between the two states is like the difference between a closed valve and an open valve. This kind of a release is like the unsealing of an over-pressurized pipeline."

These immediate methane releases in the ESAS could be triggered at any moment by seismic or tectonic events, the subsiding of sediments caused by hydrate decay or sediment sliding due to permafrost degradation and thaw. The ESAS is particularly prone to these immediate shifts because it is three times shallower than the mean depth of the continental shelf of the world ocean.

"This means that probability of dissolved methane to escape from the water column to the atmosphere is from three to 10 times greater than anywhere in the world's oceans," Shakhova said. "In the ESAS, methane is predominantly transported as bubbles. Methane bubbles rise to the surface at a speed from 10 to 40 cm s-1; this means that it only takes minutes for methane to reach the water surface and escape to the atmosphere."
link (http://www.truth-out.org/news/item/28490-the-methane-monster-roars)


Quote
Even the relatively staid IPCC has warned of such a scenario: “The possibility of abrupt climate change and/or abrupt changes in the earth system triggered by climate change, with potentially catastrophic consequences, cannot be ruled out. Positive feedback from warming may cause the release of carbon or methane from the terrestrial biosphere and oceans.”

In the last two centuries, the amount of methane in the atmosphere has increased from 0.7 parts per million to 1.7 parts per million. The introduction of methane in such quantities into the atmosphere may, some climate scientists fear, make increases in the global temperature of four to six degrees Celsius inevitable.

And keep in mind that the various major assessments of future global temperatures seldom assume the worst about possible self-reinforcing climate feedback loops like the methane one.

Here’s the question: Could some version of extinction or near-extinction overcome humanity, thanks to climate change — and possibly incredibly fast? Similar things have happened in the past. Fifty-five million years ago, a five degree Celsius rise in average global temperatures seems to have occurred in just 13 years, according to a study published in the October 2013 issue of the Proceedings of the National Academy of Sciences.

Atmospheric and marine scientist Ira Leifer is particularly concerned about the changing rainfall patterns a recently leaked IPCC draft report suggested for our future: “When I look at what the models predicted for a 4C world, I see very little rain over vast swaths of populations. If Spain becomes like Algeria, where do all the Spaniards get the water to survive? We have parts of the world which have high populations which have high rainfall and crops that exist there, and when that rainfall and those crops go away and the country starts looking more like some of North Africa, what keeps the people alive?”

The IPCC report suggests that we can expect a generalized shifting of global rain patterns further north, robbing areas that now get plentiful rain of future water supplies. History shows us that when food supplies collapse, wars begin, while famine and disease spread. All of these things, scientists now fear, could happen on an unprecedented scale, especially given the interconnected nature of the global economy.
link (http://www.salon.com/2013/12/17/the_great_dying_redux_shocking_parallels_between_ancient_mass_extinction_and_climate_change_partner/)

 

 

Title: Re: Ice-free Arctic
Post by: 5to10 on February 21, 2017, 06:40:44 PM
Cld_Yama:

Though I am a layman, I am inclined to agree with you intuitively.

How on earth could anyone imagine anything but total societal collapse in the next 5-10 years, given the plethora of available information? Discount "cherry pickers" all you want, but have you looked around and noticed the orchard is becoming a lot more productive as time progresses?

The way I see it... If we're truly dealing with exponential change and not just a phase.. We are fucked in 5-10 years (society collapses). In the past, yearly temperature records may have been broken every several years. More recently, years have been breaking the priors records for temperature consecutively. Then, months began breaking their own records consecutively.

I don't have to be a learned scientist to grasp that if this is not just a phase, but an exponential longterm trend, that soon it will be weeks and perhaps even days in the very near future.

As an audio guy, I know feedback always starts quietly, seems to rise in a linear manner.. until it just suddenly stops seeming linear anymore and it almost immediately blows your speakers.

You people know all this. I'm not a scientist, again, but even a layman can grasp that potentially none of you are able to account for all current feedback mechanisms at play here, or exactly how the effects of an ice free arctic will cascade into other fields of envirosci, and that it's unlikely any of the models can be accurate in relation to time (at least when it comes to ice-free or EIF arctic). Are you not able to recognize that these flaws likely pop up in other fields.. that a lot of models are wrong or missing key things.. That perhaps, it's nigh impossible to model the apocalypse?

All I'm saying is, depending on the severity of the feedback mechanisms related to global warming, I seem to land on the conclusion that we have WAY less time than commonly predicted.

Am I not wrong in stating that according to the temperature inversion thread, NO models on arctic warming have thus far accounted for the feedback mechanisms (Specifically water vapour in that thread, if any, certainly not all of them?) Then my god, how do you come to any conclusion other than rapid collapse? This planet is so intimately connected that I just cannot picture anything other than a rapid plunge into chaos once the arctic remains ice free. Dominoes will just continue to topple after that.

I simply cannot believe anyone who says they know the full consequences or the speed of the consequences related to an ice free arctic, but my intuition screams that our downfall will be fast and furious afterwards. Pull your lungs out of your body and see how life is afterwards. Crude comparison, but the point is there. That is an absolutely phenomenal amount of change in a phenomenally short period of time.
Title: Re: Ice-free Arctic
Post by: Martin Gisser on February 21, 2017, 07:42:43 PM
I have stopped worrying about the subsea methane bomb - and decided waiting for news from paleo climatologists, i.e. what happened during the last deglaciation. But haven't yet heard (come across) anything.

Land based permafrost melting seems to be not such a methane bomb: Soil microbes will convert much into CO2 (said Tim Lenton).
Title: Re: Ice-free Arctic
Post by: meddoc on February 21, 2017, 07:56:21 PM
I have stopped worrying about the subsea methane bomb - and decided waiting for news from paleo climatologists, i.e. what happened during the last deglaciation. But haven't yet heard (come across) anything.

Land based permafrost melting seems to be not such a methane bomb: Microbes will convert much into CO2 (said Tim Lenton).

Maybe then, You should "only" be concerned about:
1) albedo feedback kicking in- dark ocean water absorbs 9 times as much heat (so what 'd happen if You got a salary rise of 9x, instantaneously...)
2) latent heat "bomb": as soon as the last chunk of ice is gone, all that heat 334 kJ/kg will go into warming the water at 4,2 kJ/kg per Celsius (again, another exponential and instantenous salary rise)

I guess these, two alone are enough- even without the methane bomb to slingshot the global temperature catastrophically.

PS: to understand basic Physics You don't need to talk to paleoclimatologists.
Title: Re: Ice-free Arctic
Post by: Neven on February 21, 2017, 09:04:54 PM
Welcome, 5to10, your profile has been released.

Cld_Yama:

Though I am a layman, I am inclined to agree with you intuitively.

How on earth could anyone imagine anything but total societal collapse in the next 5-10 years, given the plethora of available information? Discount "cherry pickers" all you want, but have you looked around and noticed the orchard is becoming a lot more productive as time progresses?

The way I see it... If we're truly dealing with exponential change and not just a phase.. We are fucked in 5-10 years (society collapses). In the past, yearly temperature records may have been broken every several years. More recently, years have been breaking the priors records for temperature consecutively. Then, months began breaking their own records consecutively.

I don't have to be a learned scientist to grasp that if this is not just a phase, but an exponential longterm trend, that soon it will be weeks and perhaps even days in the very near future.

As an audio guy, I know feedback always starts quietly, seems to rise in a linear manner.. until it just suddenly stops seeming linear anymore and it almost immediately blows your speakers.

You people know all this. I'm not a scientist, again, but even a layman can grasp that potentially none of you are able to account for all current feedback mechanisms at play here, or exactly how the effects of an ice free arctic will cascade into other fields of envirosci, and that it's unlikely any of the models can be accurate in relation to time (at least when it comes to ice-free or EIF arctic). Are you not able to recognize that these flaws likely pop up in other fields.. that a lot of models are wrong or missing key things.. That perhaps, it's nigh impossible to model the apocalypse?

All I'm saying is, depending on the severity of the feedback mechanisms related to global warming, I seem to land on the conclusion that we have WAY less time than commonly predicted.

Am I not wrong in stating that according to the temperature inversion thread, NO models on arctic warming have thus far accounted for the feedback mechanisms (Specifically water vapour in that thread, if any, certainly not all of them?) Then my god, how do you come to any conclusion other than rapid collapse? This planet is so intimately connected that I just cannot picture anything other than a rapid plunge into chaos once the arctic remains ice free. Dominoes will just continue to topple after that.

I simply cannot believe anyone who says they know the full consequences or the speed of the consequences related to an ice free arctic, but my intuition screams that our downfall will be fast and furious afterwards. Pull your lungs out of your body and see how life is afterwards. Crude comparison, but the point is there. That is an absolutely phenomenal amount of change in a phenomenally short period of time.
Title: Re: Ice-free Arctic
Post by: 5to10 on February 21, 2017, 09:58:05 PM
Thanks, and sorry if I come off as alarmist or doomsdayish. However from all the information I've processed the past few months, I have trouble ending up elsewhere.

I appreciate all the posters here, this is a wealth of information that very few seem aware of.
Title: Re: Ice-free Arctic
Post by: rboyd on February 21, 2017, 11:00:16 PM
I am also not a scientist, but it does make sense to me that the reduced albedo effect itself will have huge, and not fully understood, impacts upon the Northern Hemisphere weather patterns and climatic conditions. Methane releases and other impacts would simply be the icing on the disaster cake.

The range of possibilities, and the chaotic conditions inherent in a move to a new equilibrium state, would be enough to severely test any nation. We should not underestimate though, the ability of some nations to survive such changes. Things may be really "shitty", but civilization may not completely collapse.

One possibility that I have seen is that the rapid reduction in temperature gradients in the NH will drive us to an much more equible climate, as the Hadley Cell rapidly moves northwards, and the
Polar and Ferrell cells are removed as a barrier to warm air moving northward. This paper seems to point to a relatively small variation in the temperature gradient being required for such a change:

https://www.fields.utoronto.ca/programs/scientific/10-11/biomathstat/Langford_W.pdf (https://www.fields.utoronto.ca/programs/scientific/10-11/biomathstat/Langford_W.pdf)

The recent storms tracking heat and moisture into the polar region may be a precursor of this phenomenon. I havn't seen any recent papers on this, and would much appreciate if anyone could point me to them. I am not saying that this will happen, it is just one of the many bad possible outcomes from the huge arctic experiment that we are running.
Title: Re: Ice-free Arctic
Post by: Martin Gisser on February 22, 2017, 02:28:41 AM
I didn't say I stopped worrying about all things Arctic. Just, the only bomb I worry about is still the A-bomb.

I'm not buying into guru Guy McPherson's scare story of imminent extinction. Nope, I worry more about BAU followed by non-extinction long after I'm dead, ca. 2100. The McPherson scenario is just another excuse to throw up hands and do/learn nothing. That is worrying me more and more.
Title: Re: Ice-free Arctic
Post by: Martin Gisser on February 22, 2017, 02:49:41 AM
PS: to understand basic Physics You don't need to talk to paleoclimatologists.
Maybe I should ask in the "stupid questions" thread - but this seems worth more a "basic questions" thread:

What global average temperature increase do climate models predict for ice free Arctic?
Title: Re: Ice-free Arctic
Post by: Tony Mcleod on February 22, 2017, 06:04:31 AM
Too many people concerned with what the deniers will say or the masses will think.

i think i know how you mean it but the way you say it it's missing an important point. some of the reasons why humans as a whole don't change their habits fast enough to make a timely change are:

a) that deniers feed them with welcome fake news that fits their needs to continue the old, ego-centred lazy path.

b) too many people don't care and/or fall for "a)" and hence continue their destructive path

hence it indeed matters, basically ONLY matters what the masses think and in that context what the deniers say
if we, who do NOT DENY and who are willing to adapt and make changes in our lives can spread the news fast enough and have a chance to see for changes in a timely manner.

i hope it's clear that this post is not meant like who is right or not but giving some input to consider as to whether we should care about the masses or not. about the hard core deniers we can do little because they deny for interests like power and money and belonging to their chosen group more than due to genuine ignorance. i believe that most of the famous and influencing hard-core deniers speak out against better knowledge, similar to ancient popes who had children and fu...ed around while preaching abstinence and chastity.

Agree. Climate change mitigation will be decided in the court of public opinion and those opinions are heavily swayed by clever denier memes that find there way onto faux news. Those memes include opportunities to mock predictions like "ice-free".

I'm running with Meirion's ice-free from Svalbard to the pole and back. In fact I just used it over at Lets Sneer at that (WUWT). I'll see if I get any nibbles.
Title: Re: Ice-free Arctic
Post by: JMP on February 22, 2017, 07:50:25 AM
We should learn a great deal in the first few years after "ice-free".   It's definitely going to be a great demarcation and possibly a tipping point. 

Of note... if water vapor as an atmospheric conveyor of additional warmth to the arctic increases, we may see summer melt stall, but autumn melt increase with more severely reduced ice growth in winter and spring.  This could potentially delay an "ice-free" arctic.  It would in no way mean that the problem was less severe.  This might mean that worsening follows a different trajectory than expected.  While I cannot predict this... it does seem consistent with recent meteorology.   

On the other hand if there is an "ice-free" arctic this year that does not mean the world is coming to an end.  The second law of thermodynamics paraphrased as heat moves automatically to cold has been perplexingly ringing in my mind for a few years now. Is it possible that Earth's atmosphere will accommodate this idea? Is it possible that in general the poles warm first?   

Mammals survived the Eocene so why shouldn't we survive this Anthropogenic Global Warming?   After all we as a species can burrow underground with the best of them.  Humans will be the last living animals on the planet - duh - have you not met one? A human will eat it's own, will sacrifice anything to survive.   Doomsday scenarios rely on people behaving as predicted.  Don't know 'bout you folk but where I'm from we don't f-ing do that.

Get real about this.  Please.

Can't remember who posted about audio feedback.   Great analysis except... no.  That's a basically closed feedback loop that doesn't occur in nature.   And, exponential itself is not one thing, yes difficult concept to get, but there are variations and different curves.  And, while nature may be described by mathematicians, nature itself isn't math. 

Science is helpful, scientists are heroes, models are imperfect, humans are imperfect, still a scientist tries to do their best.  (thankfully, I am not a scientist and can slack-off)  ;)
Title: Re: Ice-free Arctic
Post by: 5to10 on February 22, 2017, 08:00:45 AM
I posted about audio feedback. I realize it's crude and not exactly the same, but the similarities exist both in relation to feedback mechanisms at play, and the collapse of society/near or total extinction, well enough for the comparison I hope.

The changes may seem slow and steady, until suddenly they just.. aren't anymore. It doesn't take much to go from teetering on the brink to doomed, is all I mean, if there is any truth to certain apocalyptic (albeit not peer reviewed) NTHE predictions. So many phenomena happening faster than any other time in recorded history. It's just.. kind of... pointing towards bad news soon.
Title: Re: Ice-free Arctic
Post by: Martin Gisser on February 22, 2017, 03:49:59 PM
It's just.. kind of... pointing towards bad news soon.
I stopped accounting bad climate news in 2010 (which was the climatologico-agricultural prelude to the Arab Spring and the collapse of Syria).

I'm "optimistic" that bad news will keep coming for a long time, i.e. I don't expect one final bad news to end all bad news. :-)

There are many feedback loops in the Earth system, but they all have limits. No audio amplifier meltdown or speaker blow out. There are also fast balancing loops like cloud albedo or tropical lapse rate decline. And then there are slow balancing loops like rock weathering (so slow it won't save us) or ocean CO2 sequestration (300 years).
A runaway greenhouse with unchecked feedback melting down the Earth system is extremely unlikely.

But, in contrast, human systems can quickly collapse in runaway feedback. From banking panic to suigenocide by population explosion (Yemen today) there's plenty of opportunity.

But we can also devise balancing loops. A lot of that is meanwhile starting in the developing world: With careful non-destructive agriculture we can green deserts or restore desertifying land. Here is an example:
http://www.dw.com/en/sewage-effluent-fights-desertification-in-egypt/a-19318165 (http://www.dw.com/en/sewage-effluent-fights-desertification-in-egypt/a-19318165)

Problem is the carbon sequestration rate achievable by soil recarbonization. I would guess 2GtC/y is easily practicable. Agricultural soils alone could sequester a total of 500GtC (According to Rattan Lal, conventional agriculture) if not 1000GtC (my conservative estimate using biochar, making Chernozem soils).

This first anthropogenic balancing loop would be so easy to implement that industrial world technocrats can't yet wrap their heads around it. Luckily the third world is marching forward, out of necessity, for they need to feed people and retain ground water. Here are examples from the Sahel zone:
https://en.m.wikipedia.org/wiki/Yacouba_Sawadogo (https://en.m.wikipedia.org/wiki/Yacouba_Sawadogo) (ridiculously simple method invented by now famous man)
https://youtu.be/YQfhKjjEQeM (https://youtu.be/YQfhKjjEQeM) (Trees, People and Regeneration of the Sahel)

Well managed agriculture can stabilize social systems.

Yet bad agriculture is historically a major factor in collapse of civilizations and ecosystems, and ultimate cause of war. (Latest example: Syria. Yemen seems more about population explosion beyond available water resources.)
We just need to want to learn this lesson and break the power of the stupid overlords from the city.
Title: Re: Ice-free Arctic
Post by: be cause on February 22, 2017, 05:10:55 PM
Yemen being bombed back into the stone age by it's oily neighbours may have a little to do with it's current state ..
Title: Re: Ice-free Arctic
Post by: Martin Gisser on February 22, 2017, 06:34:17 PM
Yemen being bombed back into the stone age by it's oily neighbours may have a little to do with it's current state ..
I think this is an effect, not the ultimate cause. The war is a self-propelling causal feedback loop that veils the ultimate problem - as happens very often.

Here's a snippet from Years of Living Dangerously: 'Climate Wars - Yemen' with Thomas Friedman
https://youtu.be/FQTCfJe0S4w
Title: Re: Ice-free Arctic
Post by: gerontocrat on February 22, 2017, 06:42:46 PM
Yemen does have severe water resources problems. But as the US military put it, it is a threat multiplier. Add bad governance, tribal and regional rivalries and you get civil war plus regional powers conducting a proxy war.
If Russia and the USA are dumb enough to get involved even more than they are already - who knows.
Title: Re: Ice-free Arctic
Post by: jdallen on February 22, 2017, 06:50:07 PM
JMP - most posters here are not subscribing to an "end of all things" scenario when we reach an ice free Arctic.  I'd caution you about telling us to "get real"; I'd offer you the suggestion that you apply yourself to digesting the serious science which has been assembled on these forums before attempting to school us.

We will likely survive climate change as a species. There is a distinct non- zero chance that civilization might *not*, with the attendant prompt deaths of millions if not billions of human beings.

Back to topic - I'd put the probability of a sub 1 million km2 SIA pack happening this season at about 30%.  It hinges on three factors - how much insulation gets past clouds, how much open water we have at the equinox, and where PIOMAS volume stands at the start of the active melt season.

I am confident this will massively and permanently affect global circulation such that that end of season summer extent will not recover in our lifetimes, or even that of our manys great grandchildren.  In many global locations this will disrupt agriculture in profound ways which even without the prompt danger of 35C wet bulb temperatures will threaten billions of people. It is an existential threat we cannot marginalize.
Title: Re: Ice-free Arctic
Post by: 5to10 on February 22, 2017, 07:21:58 PM
JMP - most posters here are not subscribing to an "end of all things" scenario when we reach an ice free Arctic.  I'd caution you about telling us to "get real"; I'd offer you the suggestion that you apply yourself to digesting the serious science which has been assembled on these forums before attempting to school us.

We will likely survive climate change as a species. There is a distinct non- zero chance that civilization might *not*, with the attendant prompt deaths of millions if not billions of human beings.

Back to topic - I'd put the probability of a sub 1 million km2 SIA pack happening this season at about 30%.  It hinges on three factors - how much insulation gets past clouds, how much open water we have at the equinox, and where PIOMAS volume stands at the start of the active melt season.

I am confident this will massively and permanently affect global circulation such that that end of season summer extent will not recover in our lifetimes, or even that of our manys great grandchildren.  In many global locations this will disrupt agriculture in profound ways which even without the prompt danger of 35C wet bulb temperatures will threaten billions of people. It is an existential threat we cannot marginalize.

Is it not true that if civilization collapses, global warming intensifies?

So near or total extinction is certainly soon to follow after widespread collapse, no? Even partial collapse of industry/transportation will reduce dimming, which will then quickly lead to full collapse as warming hastens, correct?

So.. The pertinent question is, how long do we have left until that partial collapse happens? Is it already happening? How fast could it happen, over the course of days? Weeks? Years?

The biggest concerns seem to be food supply and economics. How do we keep this all from unraveling as our food supply is slowly devastated? It seems to me that everything is speeding up, and speeding up faster as time progresses. I can't see it taking very much longer for everything to fall apart. Everyone is too focused on the concept of TOTAL collapse or extinction via solely the consequences of climate change being "unlikely".

I don't think people are giving enough weight to the notion that only partial collapse needs to occur, which it already appears to be, for the whole thing to come crashing down soon after from the shockwave. It seems like everyone is looking at the issue in black and white: "No way warming/climate alone will kill us/collapse all of civilization in 10 yrs at this rate". Well, take into account partial collapse and partial loss of dimming and where are we left off?

Am I wrong here? I'm not the type to discount rational objection, I just see too many scenarios wherein we don't have more than 10, maybe 20 yrs left.. likely less.. and I have yet to hear or read any realistic, optimistic scenario that discredits the idea. I don't look to be pessimistic or optimistic, but realistic, and thus far this is where I'm left standing.
Title: Re: Ice-free Arctic
Post by: Milret2 on February 22, 2017, 08:14:29 PM
I didn't say I stopped worrying about all things Arctic. Just, the only bomb I worry about is still the A-bomb.

I'm not buying into guru Guy McPherson's scare story of imminent extinction. Nope, I worry more about BAU followed by non-extinction long after I'm dead, ca. 2100. The McPherson scenario is just another excuse to throw up hands and do/learn nothing. That is worrying me more and more.
[/quote

I would think, as things get progressively worse and proliferation of nuclear weapons continue to expand, it becomes inevitable that nuclear weapons will be used. Once tactical weapons are used by some group ... strategic city busters and emp release weapons will follow very soon. McPherson may well not see the climate/species collapse happen simply because, once the door is open to such weapons in the next decade or so he, and many of the rest of us, will be dead from such things.

I can see where there can be arguments of high quality regards when and how quickly the loss of polar ice will affect our ecology, I just also feel it is human greed and murderous tendencies pushed by ecological changes that has the best chance ( and very soon) to end life on this planet.
Title: Re: Ice-free Arctic
Post by: Milret2 on February 22, 2017, 08:17:14 PM
My apologies for not using the "quote" mechanism properly. Very new here 😖
Title: Re: Ice-free Arctic
Post by: Neven on February 22, 2017, 08:37:24 PM
Should I rename this thread to People-free Planet?  ;)
Title: Re: Ice-free Arctic
Post by: 5to10 on February 22, 2017, 08:54:11 PM
Should I rename this thread to People-free Planet?  ;)

Man, I would love to have a more optimistic perspective, but optimism is not realism.

Personally, if I'm being irrational in my perspective, I want to know so that I can think rationally about it instead. I have not come across much of any realistic, optimistic information that discredits at the very least a near term partial collapse of civilization scenario, which has immediate effects on dimming, which will just continue to snowball...

Ice-free arctic seems like the first in a series of rapid, extreme incoming global changes. This cannot be good.
Title: Re: Ice-free Arctic
Post by: Csnavywx on February 22, 2017, 10:00:11 PM
Argh. This thread is getting a bit frustrating. Can we start posting some science in here? I mean, speculation is fine, so long as it is presented as just that -- speculation.

By the way, are we talking JUST about ice free in the summer or ice free all year-round (before I start posting literature)? Or both?
Title: Re: Ice-free Arctic
Post by: rboyd on February 22, 2017, 10:01:20 PM
Given an immediate/imminent crisis, government's can rapidly turn around and do whatever is necessary - including things that were "off limits" previously. In the 2008 financial they printed trillions and bailed out whoever necessary to keep things going. In World War 2 they imposed a centrally planned economy and redirected society within months.

A good example is that of Cuba after the collapse of the Soviet Union in the early 1990's, they had to totally redesign their agricultural system and economy without the cheap oil and subsidies from their communist friends. People lost weight in the first few years (an average of about 12-20 pounds), and actually got healthier, until the new organic agricultural systems started to provide more food.

https://www.oxfamamerica.org/static/oa4/OA-CubaGoingAgainstGrain_FoodCrisis.pdf (https://www.oxfamamerica.org/static/oa4/OA-CubaGoingAgainstGrain_FoodCrisis.pdf)

https://www.theatlantic.com/health/archive/2013/04/how-cubans-health-improved-when-their-economy-collapsed/275080/ (https://www.theatlantic.com/health/archive/2013/04/how-cubans-health-improved-when-their-economy-collapsed/275080/)

We have so much waste in our societies, the basics could be kept going through central planning and rationing. Depends on the quality of governance and the resources available of course.

Now back to the science, and posting this stuff in the right place.
Title: Re: Ice-free Arctic
Post by: ritter on February 22, 2017, 10:11:37 PM
Should I rename this thread to People-free Planet?  ;)

Man, I would love to have a more optimistic perspective, but optimism is not realism.

Personally, if I'm being irrational in my perspective, I want to know so that I can think rationally about it instead. I have not come across much of any realistic, optimistic information that discredits at the very least a near term partial collapse of civilization scenario, which has immediate effects on dimming, which will just continue to snowball...

Ice-free arctic seems like the first in a series of rapid, extreme incoming global changes. This cannot be good.

It's hard to get a clear reading on the tea leaves these days. Your concern is understandable and I share it, rational or not. I think most of us are well aware that we are in uncharted territory with the sheer number of humans and the changes we've wrought on the environment. There are a great many converging "threat multipliers" out there.

Science is working the problem but tends to be behind the pace of events. Not the fault of scientists, just the nature of the rate of change and the rate of science. None of us know what is going to happen or when. So, don't forget to live life--it's the only one we get.  Whether it ends tomorrow or in 90 years is no more certain today than it ever has been.
Title: Re: Ice-free Arctic
Post by: Tony Mcleod on February 22, 2017, 10:49:29 PM
Argh. This thread is getting a bit frustrating. Can we start posting some science in here? I mean, speculation is fine, so long as it is presented as just that -- speculation.

By the way, are we talking JUST about ice free in the summer or ice free all year-round (before I start posting literature)? Or both?

Well, the intention was merely to re-frame the "ice-free" summer = <1msqkm meme with one that was less likely to provide ammo for deniers. But I am finding the subsequent conversation interesting. I hope it doesn't veer to far into unsubstantial speculation.

My take is that modern 'western' humans live within such a complex, fragile, interlinked system that it won't take much at all to disrupt. There are innumerable catalysts to set collapse moving. It could be a Tokyo earthquake or a bomb going off in Tel Aviv or someone sneezing in Hong Kong... Abrubt climate change will probably be a bit like kicking a bloke while he's down.

But it's not something I lose sleep over. Do the least harm I can and be happy. All species go extinct.

Perhaps I should have named the thread: Credible "Ice-free" Arctic meme
Title: Re: Ice-free Arctic
Post by: Csnavywx on February 22, 2017, 11:46:44 PM
The problem with trying to re-frame the problem around the deniers is that you end up catering to them. It's one thing to be conservative and allow criticism to help, it's quite another to let the tail wag the entire dog. In this case, they'll just move the goalposts and mock something else once <1 M km^2 is reached.

The key to engaging is to ask what it would take to convince them that AGW is real. Ask them what would falsify their personal position and ask them to be specific. Make them stake it out, because if you don't, they'll set up a treadmill of "well what about..." and drag it into the weeds. You can tell if someone is open to being challenged pretty much right away using this method. Don't waste your time if they aren't willing to even do that, because a non-falsifiable position is by default either opinion, speculation or faith-based. It automatically can't be scientific.

In regards to making the ice-free label more specific, one would need to figure out a way of doing that objectively. We know there's going to be some melt-resistant ice that hugs the coast up there in the coastal areas of the CAA and Greenland. The trick is trying to quantify that and forecast when that sliver disappears.

Beyond that, I think modeling SSTs in the peripheral seas and continuing work on atmospheric circulation changes is more warranted. There's quite a difference between 0C open water and 10C open water, for instance, when it comes to clouds, precip and convection.
Title: Re: Ice-free Arctic
Post by: Martin Gisser on February 23, 2017, 03:02:08 AM
Should I rename this thread to People-free Planet?  ;)
Maybe "Ice-free Arctic & People-free Planet"...

Just came across another "near term climate catastrophe" video, where ice-free Arctic is the starting point. Guy McPherson declares: "I think we're headed for at least 8.7°C temperature rise within the next decade". (Wrrrrr... it was more fun watching Lord Monckton proudly proclaim his denier nonsense...)

Here's an alternative scenario. Dunno how scientifically sound it is.
Ice-free Arctic will change northern hemisphere circulation in a way that actually benefits agriculture. Except for more superstorms and yearly 1000y floods somewhere. Yet the Mediterranean will not dry out. The Sahara will shrink. The Great Green Wall of Africa reforestation project will provide jobs and food for millions.
Title: Re: Ice-free Arctic
Post by: 5to10 on February 23, 2017, 04:08:40 AM
Should I rename this thread to People-free Planet?  ;)
Maybe "Ice-free Arctic & People-free Planet"...

Just came across another "near term climate catastrophe" video, where ice-free Arctic is the starting point. Guy McPherson declares: "I think we're headed for at least 8.7°C temperature rise within the next decade". (Wrrrrr... it was more fun watching Lord Monckton proudly proclaim his denier nonsense...)

Here's an alternative scenario. Dunno how scientifically sound it is.
Ice-free Arctic will change northern hemisphere circulation in a way that actually benefits agriculture. Except for more superstorms and yearly 1000y floods somewhere. Yet the Mediterranean will not dry out. The Sahara will shrink. The Great Green Wall of Africa reforestation project will provide jobs and food for millions.

Ice core samples indicate that earth has experienced a period of 1c warming as well as 5-10c warming *per year* in the past. It is not impossible. Anthropogenic climate change is moving things along faster than any other time we know of. I'm not sure why it seems so outlandish when evidence shows things are warming up and there seem to be positive feedbacks stacking more and more as time progresses..
Title: Re: Ice-free Arctic
Post by: Glenn Tamblyn on February 23, 2017, 04:24:51 AM
5to10

Got a reference for that claim about rate of warming?
Title: Re: Ice-free Arctic
Post by: 5to10 on February 23, 2017, 04:34:33 AM
5to10

Got a reference for that claim about rate of warming?

I didn't delve into it much further, but this video explains the warming periods.

https://www.youtube.com/watch?v=siWCXOypJh4&t=1s (https://www.youtube.com/watch?v=siWCXOypJh4&t=1s)
Title: Re: Ice-free Arctic
Post by: Martin Gisser on February 23, 2017, 04:43:08 AM
Yes, such rapid changes happened. They were local. I don't think that circulation changes from ice-free Arctic could do that now. There was more going on when the huge ice shield dissolved at the last deglaciation, with huge meltwater lakes suddenly gushing into the ocean:
Quote
Lake Agassiz's major drainage reorganization events were of such magnitudes that they had significant impact on climate, sea level and possibly early human civilization. Major freshwater release into the Arctic Ocean is considered to disrupt oceanic circulation and cause temporary cooling. The draining of 13,000 years ago may be the cause of the Younger Dryas stadial.[1][8][9] The draining at 9,900–10,000 years ago may be the cause of the 8,200 yr climate event.
https://en.wikipedia.org/wiki/Lake_Agassiz
Title: Re: Ice-free Arctic
Post by: 5to10 on February 23, 2017, 05:19:29 AM
Yes, such rapid changes happened. They were local. I don't think that circulation changes from ice-free Arctic could do that now. There was more going on when the huge ice shield dissolved at the last deglaciation, with huge meltwater lakes suddenly gushing into the ocean:
Quote
Lake Agassiz's major drainage reorganization events were of such magnitudes that they had significant impact on climate, sea level and possibly early human civilization. Major freshwater release into the Arctic Ocean is considered to disrupt oceanic circulation and cause temporary cooling. The draining of 13,000 years ago may be the cause of the Younger Dryas stadial.[1][8][9] The draining at 9,900–10,000 years ago may be the cause of the 8,200 yr climate event.
https://en.wikipedia.org/wiki/Lake_Agassiz

All he is suggesting is that abrupt climate changes can and have occurred, and are occurring right now, is he not?

There may have been "more going on" then in terms of the root causes of that particular chaotic warming/cooling cycle. But we're not dealing with the same root of a potential abrupt change. Different scenario now.

I mean, the arctic is not going to cause the same type of rapid change. But just considering albedos alone and how quickly that could change ocean temps... Hell, the temperature inversion thread.. How can you say it won't cause SOME TYPE of rapid change? Civilization is built on a very precarious tightrope. If things change too much, too quickly, large parts of it will break down soon after. Losing essentially all of the ice in the arctic and exposing a dark ocean may be a massive global change that ends up being too much, too quick. It's not an unreasonable statement. We just have to wait and see.

Nobody can accurately model or predict what is to come.
Title: Re: Ice-free Arctic
Post by: Pmt111500 on February 23, 2017, 07:12:48 AM
Re:People-free Planet : Imho there's not much point in talking of this here until it happens, if that sounds like a contradiction it is. Just recently saw a documentary in which a guy (checked: Levison Wood) walked most of the lenght of the Nile. On the way he met an ex-military who was happy to have a farm in the middle of a mine field in South Sudan (which could use a better name) after a more intense period of civil war. Said it keeps the intruders mostly out.

Re:Ice-free Arctic is too long to write on the phone.
Title: Re: Ice-free Arctic
Post by: DoomInTheUK on February 23, 2017, 09:46:07 AM
.... alternative scenario. Dunno how scientifically sound it is.
Ice-free Arctic will change northern hemisphere circulation in a way that actually benefits agriculture. Except for more superstorms and yearly 1000y floods somewhere. Yet the Mediterranean will not dry out. The Sahara will shrink. The Great Green Wall of Africa reforestation project will provide jobs and food for millions.

As a betting man, my money would be against it. The old Arctic provided a stabilising influence to the climate. Jet streams might have wandered a little but on average they were in their usual places.
Agriculture depends on this stability for the growing season.

This "new and improved" Arctic (now with added storms and upto 95% ice free) will allow much more variation. Yes some years may be better, but some will be worse. I'd say on average it'll be worse. Those stable jet streams year after year really do help keep the food on your plate.
Title: Re: Ice-free Arctic
Post by: 5to10 on February 23, 2017, 09:52:09 AM
.... alternative scenario. Dunno how scientifically sound it is.
Ice-free Arctic will change northern hemisphere circulation in a way that actually benefits agriculture. Except for more superstorms and yearly 1000y floods somewhere. Yet the Mediterranean will not dry out. The Sahara will shrink. The Great Green Wall of Africa reforestation project will provide jobs and food for millions.

As a betting man, my money would be against it. The old Arctic provided a stabilising influence to the climate. Jet streams might have wandered a little but on average they were in their usual places.
Agriculture depends on this stability for the growing season.

This "new and improved" Arctic (now with added storms and upto 95% ice free) will allow much more variation. Yes some years may be better, but some will be worse. I'd say on average it'll be worse. Those stable jet streams year after year really do help keep the food on your plate.

.... alternative scenario. Dunno how scientifically sound it is.
Ice-free Arctic will change northern hemisphere circulation in a way that actually benefits agriculture. Except for more superstorms and yearly 1000y floods somewhere. Yet the Mediterranean will not dry out. The Sahara will shrink. The Great Green Wall of Africa reforestation project will provide jobs and food for millions.

As a betting man, my money would be against it. The old Arctic provided a stabilising influence to the climate. Jet streams might have wandered a little but on average they were in their usual places.
Agriculture depends on this stability for the growing season.

This "new and improved" Arctic (now with added storms and upto 95% ice free) will allow much more variation. Yes some years may be better, but some will be worse. I'd say on average it'll be worse. Those stable jet streams year after year really do help keep the food on your plate.

I think it will be worse far more often, and soon. Look at Cali right now. There will be even more excess water vapour as a result of an ice free arctic, in conjunction with unstable jet streams, this is a volatile combo.
Title: Re: Ice-free Arctic
Post by: Archimid on February 23, 2017, 11:56:22 AM

Here's an alternative scenario. Dunno how scientifically sound it is.

I think your scenario is extremely unlikely, unless there is some magical force that makes species magically adapt and magically changes human infrastructure to thrive under new climatic parameters. The default for natural behavior is that when there are large sudden changes in the climate, mass extinction ensues.


Quote
Ice-free Arctic will change northern hemisphere circulation in a way that actually benefits agriculture. Except for more superstorms and yearly 1000y floods somewhere
.

The superstorms and 1000 year floods are already happening and we still have an arctic within 3SD of historic values. They will only get worse. As far as agriculture, I'm sure some areas will become more crop friendly, but current infrastructure will be stressed by the changes and some of it will be completely destroyed.

It is absolute madness to think agriculture will not be disrupted. It is not only  floods, droughts, heatwaves and irregular seasonality. New diseases will crop up and old diseases will move north.  Only a 10-15 percent reduction in global crops will be enough to send many countries spiraling out of control. I bet the disruptions will be larger than that.

Quote
Yet the Mediterranean will not dry out. The Sahara will shrink.

The Mediterranean will not dry out, but many water reservoirs will as glacials melt and  snow cover disappears earlier and earlier drying streams and lakes.

The Sahara might shrink, but other deserts might expand and entirely new deserts created. Infrastructure in the Sahara that's dependent on certain dryness will be overwhelmed. People perfectly adapted to the desert will lose their livelihood.

Quote
The Great Green Wall of Africa reforestation project will provide jobs and food for millions.

??? That's just a pipe dream.  Current geopolitics indicate the complete opposite to that.
Title: Re: Ice-free Arctic
Post by: wili on February 23, 2017, 12:18:50 PM
Archemid, don't be such a pessimist. Look how wonderfully things are turning out for the good people of South Sudan, after all!  :) :-[ >:(

http://www.cnn.com/2017/02/20/africa/south-sudan-famine/ (http://www.cnn.com/2017/02/20/africa/south-sudan-famine/)
Title: Re: Ice-free Arctic
Post by: gerontocrat on February 23, 2017, 01:27:39 PM
South Sudan is mostly a man-made famine - totally cynical behaviour by local rival politicians.

But as with Syria and Yemen, demonstrates what happens when man's greed and fear fueled by stupidity compounds natural events.

If you want to scare yourself into a dystopian view of the future try spending some time studying chaos theory.  Perhaps an acceleration in sea ice decline leading greatly enhanced insolation leading to dramatic climate change could be a trigger.

But this stuff belongs in consequences. Is not this thread about defining ice free and some evidence-based speculation about when ?
Title: Re: Ice-free Arctic
Post by: Pmt111500 on February 23, 2017, 01:31:54 PM
(re:south sudan) Yes, I'd imagine in such situation having a farm on a mine field would be quite ok.

To distract from impending doom that's going to kill us all by nukes, here's some science touching this arctic sea ice issue, a japanese study few years back (2011) modelling the circulation of the warm phase of pliocene (3Ma - mega-annum ago). Some of this looks quite a lot like what we're seeing on the most extreme anomalies currently. Of course the big thing missing from Pliocene is the Greenland Ice Sheet, so it would be going next if we keep this thing up. Note also the warming of the southern ocean, still the Antarctica keeps cold, but of course some of wais would be gone.
Title: Re: Ice-free Arctic
Post by: Hefaistos on February 23, 2017, 01:58:55 PM
I think it will be worse far more often, and soon. Look at Cali right now. There will be even more excess water vapour as a result of an ice free arctic, in conjunction with unstable jet streams, this is a volatile combo.

This is an interesting topic!
I really don't understand how less ice in the Arctic creates floods in CA, would appreciate if you could please explain the mechanism! In what way was the jet stream conducive to bring about the atmosperic river that hit CA?
Title: Re: Ice-free Arctic
Post by: Archimid on February 23, 2017, 02:46:33 PM
Thanks for moving this thread here Neven. As always, good call.


This is an interesting topic!
I really don't understand how less ice in the Arctic creates floods in CA, would appreciate if you could please explain the mechanism! In what way was the jet stream conducive to bring about the atmosperic river that hit CA?

Maybe this links gives you a visual aide: http://tropic.ssec.wisc.edu/real-time/mtpw2/product.php (http://tropic.ssec.wisc.edu/real-time/mtpw2/product.php)

Do you see the arms of moisture extending North? As the temperature difference between the Arctic and the tropics decreases, the arms will extend longer and become more loaded with water.  This will not only highly increase the moisture over the Arctic, but it will change the periodicity and magnitude of  atmospheric rivers that reach land.  I bet this will cause both droughts and floods at different times.

At least that's how I understand it.

Title: Re: Ice-free Arctic
Post by: citrine on February 23, 2017, 04:01:25 PM
More on climate change in general and the California floods:
http://mashable.com/2017/02/22/california-rivers-in-the-sky-flooding-climate/#mXZuc7c3Z5qj (http://mashable.com/2017/02/22/california-rivers-in-the-sky-flooding-climate/#mXZuc7c3Z5qj)
Title: Re: Ice-free Arctic
Post by: Sigmetnow on February 23, 2017, 04:35:04 PM
The Arctic is already ”ice-free” for many of its inhabitants.
Title: Re: Ice-free Arctic
Post by: Archimid on February 23, 2017, 04:37:32 PM
Every time I see the image of a polar bear I feel literally nauseous with guilt.
Title: Re: Ice-free Arctic
Post by: be cause on February 23, 2017, 04:40:56 PM
Archimid ..think instead of all the relieved seals ..
Title: Re: Ice-free Arctic
Post by: gerontocrat on February 23, 2017, 04:53:09 PM
I guess that seals adapted to the high arctic climate  will not do well as the Arctic melts.
Title: Re: Ice-free Arctic
Post by: wili on February 23, 2017, 05:45:24 PM
Things don't look too cheery in the Lake Chad Basin, either:

http://www.aljazeera.com/indepth/opinion/2017/02/lake-chad-basin-world-neglected-crisis-rages-170222104058402.html (http://www.aljazeera.com/indepth/opinion/2017/02/lake-chad-basin-world-neglected-crisis-rages-170222104058402.html)

Lake Chad Basin: World's most neglected crisis rages on

Quote
As the humanitarian scale-up in the region continues, governments and donors are urged to do their part.


ger wrote: "South Sudan is mostly a man-made famine"

That's the point. Martin G claimed that purely climate related developments might green the southern Sahara/Sahel, so Arch pointed out that politics were playing a large role in the desolation of that area. My articles are just supporting that point... (but maybe I've been misunderstanding the whole thread?)
Title: Re: Ice-free Arctic
Post by: 5to10 on February 23, 2017, 05:51:23 PM
Can anyone help me detail positive feedbacks amplified by the new arctic state?

Albedos
Methane release
oceanic warming/Water vapour
downward radiations increasing related to temperature inversion


And any negatives... if there are any worth speaking of.
Title: Re: Ice-free Arctic
Post by: Archimid on February 23, 2017, 06:01:56 PM

And any negatives... if there are any worth speaking of.

Clouds may help out during summer.  Greenland melt should help out year round at the cost of SLR.
Title: Re: Ice-free Arctic
Post by: 5to10 on February 23, 2017, 06:27:44 PM

And any negatives... if there are any worth speaking of.

Clouds may help out during summer.  Greenland melt should help out year round at the cost of SLR.

I thought clouds were projected to be a net positive?

As for melt.. Won't full sun on the open ocean heavily outweigh any cooling caused by it? Seems like nowhere near enough of an influence?
Title: Re: Ice-free Arctic
Post by: Martin Gisser on February 23, 2017, 06:31:41 PM
Martin G claimed that purely climate related developments might green the southern Sahara/Sahel, so Arch pointed out that politics were playing a large role in the desolation of that area. My articles are just supporting that point... (but maybe I've been misunderstanding the whole thread?)
Please note I was just playing "non-devil's advocate". My only claim is that my scenario is not worse "science" than Guy McPherson's stuff.

I'm well aware of bad things at Lake Chad, South Sudan, Darfur, etc.

According to  the map presented above by Pmt111500, Lake Chad and the Sahel might well benefit from ice-free Arctic.  For some more non-devil's advocacy google "John Liu Rwanda". Africa is learning fast that ecosystem restoration and non-destructive agriculture gives multiple beneficial returns within just a few years. Methinks the Great Green Wall of Africa is not that far away anymore. In the Marrakesh 2016 climate talks it dawned who will be the pioneers of serious climate engineering. It will not be the rocket scientists of industrial civilization:

Agri-Culture can be a serious negative feedback.
Title: Re: Ice-free Arctic
Post by: 5to10 on February 23, 2017, 06:55:47 PM
Martin G claimed that purely climate related developments might green the southern Sahara/Sahel, so Arch pointed out that politics were playing a large role in the desolation of that area. My articles are just supporting that point... (but maybe I've been misunderstanding the whole thread?)
Please note I was just playing "non-devil's advocate". My only claim is that my scenario is not worse "science" than Guy McPherson's stuff.

I'm well aware of bad things at Lake Chad, South Sudan, Darfur, etc.

According to  the map presented above by Pmt111500, Lake Chad and the Sahel might well benefit from ice-free Arctic.  For some more non-devil's advocacy google "John Liu Rwanda". Africa is learning fast that ecosystem restoration and non-destructive agriculture gives multiple beneficial returns within just a few years. Methinks the Great Green Wall of Africa is not that far away anymore. In the Marrakesh 2016 climate talks it dawned who will be the pioneers of serious climate engineering. It will not be the rocket scientists of industrial civilization:

Agri-Culture can be a serious negative feedback.

Yes but it's foolish to suggest that the entirely possible (if not probable) near term collapse of important, already existing agricultural systems as a result of inconsistent/more extreme weather (Look at calis recent rainfall..) would not heavily outweigh the minutia of effects of farming in locales you're suggesting. This does not seem a rational perspective. Not to mention the cascading effects that collapse would have.

There is really no reason to go beyond a few simple questions with this whole situation the world is facing: "Are there more positive warming feedbacks than negatives? Is the gap between their influence increasing? How fast?"

Without the negatives, we are fucked, very near term. No amount of farming in Sudanese minefields is going to have any measurable impact on what's already in motion. Sure, if everything else weren't falling apart at the same time, it might be great. But it seems way too little too late at this point.
Title: Re: Ice-free Arctic
Post by: AbruptSLR on February 23, 2017, 07:36:42 PM
The problem with trying to re-frame the problem around the deniers is that you end up catering to them. It's one thing to be conservative and allow criticism to help, it's quite another to let the tail wag the entire dog.

The linked article is entitled: "Judith Curry confuses laypeople about climate models".  While I think the article errs on the side of least drama; I think that it does illustrate how impossible it is to appease denalists.


https://andthentheresphysics.wordpress.com/2017/02/21/judith-curry-confuses-laypeople-about-climate-models/

Extract: "Judith Curry has written a report for the Global Warming Policy Foundation called Climate Models for the layman. As you can imagine, the key conclusions is that climate models are not fit for the purpose of justifying political policies to fundamentally alter world social, economic and energy systems. I thought I would comment on the key points.

-   GCMs have not been subject to the rigorous verification and validation that is
the norm for engineering and regulatory science.


Well, yes, this is probably true. However, it’s primarily because we only have one planet and haven’t yet invented a time machine. We can’t run additional planetary-scale experiments and we can’t go back in time to collect more data from the past.

-   There are valid concerns about a fundamental lack of predictability in the complex
nonlinear climate system.


This appears to relate to the fact that the system is non-linear and, hence, chaotic. Well, that it is chaotic does not mean that it can vary wildly; it’s still largely constrained by energy balance."
Title: Re: Ice-free Arctic
Post by: Mozi on February 23, 2017, 08:32:44 PM
The false implication being as well that what humans are currently doing to the environment is well understood and characterized - that the choice is between addressing global warming and not affecting the environment in unknown ways, when in reality our entire way of life is built around messing with systems that we do not fully understand.
Title: Re: Ice-free Arctic
Post by: Tor Bejnar on February 23, 2017, 09:30:52 PM
5to10 has a concern that once the Arctic goes essentially ice free (EIF), the water will heat up and "game's over".

I highly suspect 5to10 is under appreciating how much heat will get sent to space during the early winter, even with inversions*, etc.  The first year the high arctic loses most of its ice, it will most likely do so late in the season, and (as others have recently posted) the sun will be relative low and there will be little heating of the ice-free water.  Even over time as the high Arctic melts earlier and freezes over later, it will continue to grow thick enough to survive past the solstice.  Remember, the first half-meter grows fast and while Arctic ice volume currently peaks in April, high Arctic volume peaks even later. 

I understand two things might change this soon to be realized 'new' normal:  storms mix up warm salty waters (preventing freeze up) and storms keep the high seas ice free due to turbulence (preventing freeze up).  I expect temperatures, however, will continue to be cold enough for over a meter of ice growth for quite a while (decade or more after the first EIF).

But what I 'know' is basically gleaned from Neven's blog and forum, not from any particular expertise.
_____
* - See  “Arctic temperature layers and inversions” thread.
Title: Re: Ice-free Arctic
Post by: 5to10 on February 23, 2017, 09:39:32 PM
5to10 has a concern that once the Arctic goes essentially ice free (EIF), the water will heat up and "game's over".

I highly suspect 5to10 is under appreciating how much heat will get sent to space during the early winter, even with inversions*, etc.  The first year the high arctic loses most of its ice, it will most likely do so late in the season, and (as others have recently posted) the sun will be relative low and there will be little heating of the ice-free water.  Even over time as the high Arctic melts earlier and freezes over later, it will continue to grow thick enough to survive past the solstice.  Remember, the first half-meter grows fast and while Arctic ice volume currently peaks in April, high Arctic volume peaks even later. 

I understand two things might change this soon to be realized 'new' normal:  storms mix up warm salty waters (preventing freeze up) and storms keep the high seas ice free due to turbulence (preventing freeze up).  I expect temperatures, however, will continue to be cold enough for over a meter of ice growth for quite a while (decade or more after the first EIF).

But what I 'know' is basically gleaned from Neven's blog and forum, not from any particular expertise.
_____
* - See  “Arctic temperature layers and inversions” thread.

I mean the air would heat up too, right? And it already is without all the ice gone as temp inversion reversal (?) seems to show. Logic seems to indicate that will only speed up as there is less and less ice? Both the warming of the air and the water simultaneously, and no ice there to cool.. I imagine that will have great impact on the next seasons ice formation, is what my unlearned intuition says. If it re-freezes, it will be drastically lower than the trend until now, seems a fair position.

Even if I'm wrong in these ideas, perhaps more educated people will be inclined to think about the issue in a bit of a different way while refuting, and perhaps new info will come out of it.
Title: Re: Ice-free Arctic
Post by: Archimid on February 23, 2017, 10:08:12 PM
I mean the air would heat up too, right?

Go to Climate Reanalyzer: http://cci-reanalyzer.org/wx/DailySummary/#T2_anom (http://cci-reanalyzer.org/wx/DailySummary/#T2_anom)

Compare where the temperature anomalies are now and where the most sea ice extent is missing. I attached two images and circled what I mean. It is February, we had plenty of ice and it is 10C warmer than normal in those areas. 
Title: Re: Ice-free Arctic
Post by: 5to10 on February 23, 2017, 10:24:17 PM
I get that not one nor the other are strong enough, but we haven't reached ice free yet. I'm wondering if both warmed air and warmed water, in an essentially ice free arctic, would tip the scale.

I mean, the smaller the amount of ice = the warmer the water AND the warmer the air, so perhaps there are thresholds wherein tipping points are reached, that we have yet to meet, in regards to ice volume. We need to account for all of these variables together to reach a reasonably sound prediction. We are dealing with exponential change..

Hoping based on your info that slow and linear "appearing" is how it will continue (Though it's not really slow and linear...).
Title: Re: Ice-free Arctic
Post by: Tigertown on February 23, 2017, 10:36:21 PM
Which causes more harm? (1) A completely ice free Arctic for a month,give or take. OR (2) A really large percentage of the Arctic free of ice for multiple months. Which one will lead to more insolation and finally to more freezing season storms and high SST's, and a weaker vortex?
Title: Re: Ice-free Arctic
Post by: 5to10 on February 23, 2017, 10:44:19 PM
Which causes more harm? (1) A completely ice free Arctic for a month,give or take. OR (2) A really large percentage of the Arctic free of ice for multiple months. Which one will lead to more insolation and finally to more freezing season storms and high SST's, and a weaker vortex?

Obviously the latter, I understand that. Still I have a strong gut feeling that there are huge unforseen consequences when we hit essentially ice free even for a month, as if some kind of important threshold we haven't yet considered will be crossed either when/soon after it happens, or at some point leading up to it.
Title: Re: Ice-free Arctic
Post by: Tigertown on February 23, 2017, 10:51:10 PM
It's building up to a crescendo, no doubt. Perhaps one scenario this year, followed by the other next year. The heat is accumulating.
Title: Re: Ice-free Arctic
Post by: Archimid on February 23, 2017, 11:13:49 PM
Which causes more harm? (1) A completely ice free Arctic for a month,give or take. OR (2) A really large percentage of the Arctic free of ice for multiple months. Which one will lead to more insolation and finally to more freezing season storms and high SST's, and a weaker vortex?

For an ice free Arctic to last for just a month it would have to happen in very late September. If it happens in August, I bet the freezing will be delayed several months. I think that enough partial melts might receive higher insolation that a month of full melt late in the year, but the full melt scenario leads to more storms and weaker vortex.
Title: Re: Ice-free Arctic
Post by: oren on February 23, 2017, 11:16:08 PM
5to10, I think you are under-appreciating the power of the polar winter. The ice does not cool the air and water during the winter. When the sun goes down, the long polar night sucks the energy to space and cools everything, generating ice. Yes, storms and open water can delay refreeze, but not for 6 long months. This year we had a delay of about one month in the peripheral seas, and basically no delay at all in the central CAB itself. Should we get an almost total melt-out, I expect the refreeze delay to reach maybe 2-3 months, but it can't last the whole winter.
The normal temps in midwinter are around -30oC. It takes around -10oC to freeze relatively calm and relatively fresh open ocean water. Storms could cause a lot of turbulence and mixing. And open water venting heat could cause an added anomaly of let's say +10oC. But in a long winter there will come a calm cold day that will manage to generate an initial ice layer, which will then serve as a basis for calming the sea and generating more ice.
After such a winter, you might even still get a maximum ice extent similar to recent years. Many regions of the arctic currently stay at their max extent for 4 months or more. Even a shorter freezing season may bring them to the same extent at some point. But volume will be much lower, and the next summer even more prone to total and early melt-out. After some years like that I can't say what is going to happen, but I suggest not to get carried away with short term expectations.
Title: Re: Ice-free Arctic
Post by: 5to10 on February 23, 2017, 11:23:07 PM
5to10, I think you are under-appreciating the power of the polar winter. The ice does not cool the air and water during the winter. When the sun goes down, the long polar night sucks the energy to space and cools everything, generating ice. Yes, storms and open water can delay refreeze, but not for 6 long months. This year we had a delay of about one month in the peripheral seas, and basically no delay at all in the central CAB itself. Should we get an almost total melt-out, I expect the refreeze delay to reach maybe 2-3 months, but it can't last the whole winter.
The normal temps in midwinter are around -30oC. It takes around -10oC to freeze relatively calm and relatively fresh open ocean water. Storms could cause a lot of turbulence and mixing. And open water venting heat could cause an added anomaly of let's say +10oC. But in a long winter there will come a calm cold day that will manage to generate an initial ice layer, which will then serve as a basis for calming the sea and generating more ice.
After such a winter, you might even still get a maximum ice extent similar to recent years. Many regions of the arctic currently stay at their max extent for 4 months or more. Even a shorter freezing season may bring them to the same extent at some point. But volume will be much lower, and the next summer even more prone to total and early melt-out. After some years like that I can't say what is going to happen, but I suggest not to get carried away with short term expectations.

Thank you for the reply. I'm not meaning to suggest total loss of ice outweighs sundown, I'm just wondering how much of an effect, if any, the existence of large volumes of ice has on said temperatures. You're basically saying it's miniscule in comparison, that's good. Not that the situation looks much better.
Title: Re: Ice-free Arctic
Post by: Archimid on February 24, 2017, 02:16:41 AM
I think that there will be a point when there is so little ice that the DMI80 graph instead of showing  a plateau at around 0C, the temperature will shoot up several degrees, maybe 10C. The year that happens it will take a long time before significant ice is formed over the arctic because it will be too warm, there will be many hot air intrusions and too many waves.

But the Arctic winter is long and dark. Ice will not form in the open, warm, wavy ocean but I fail to see how ice can't form around many of the geographic features around the Arctic. That ice can eventually grow enough to calm the waves and grow. It can even grow record fast if the circumstances are favorable. However this will cause the ice to be much thinner for next summer.

The summer following the first ice free arctic will be ice free even sooner than the year before. Possibly before summer solstice. That freezing season will start much later because summer temperatures will be crazy hot (for the arctic). That cycle will repeats until the planet cools enough or there is literally 0 ice year round.

Regardless. Before we hit ice free we will know. We are all starting to feel the effects now and as the arctic approaches ice free conditions the changes will be more obvious. I bet that by the time it reaches 0 the world's climate is already quite messed up. The transition years to a fully ice free arctic will be the worst. I'm sure that some decades after the first ice free arctic, once the climate stabilizes and society has been culled, civilization can re-emerge, hopefully with lessons learned. 
Title: Re: Ice-free Arctic
Post by: Glenn Tamblyn on February 24, 2017, 02:23:57 AM
5to10

Echoing other comments. Your original post which I queried suggested multi-degree changes for 'the earth' in just years. There is no evidence that I am aware of for that happening. In contrast the video was talking very much about local changes in the Arctic and that is a whole different story. Even the ice cores show that different things happened in different parts of Greenland. So vey localised disruptions rather than global.

Could we see some dramatic switches in local Arctic climate if sea ice crashes? Yes. The circulation changes we are seeing this year suggest those possibilities. But changes of that scale globally are a whole different kettle of fish. Needing much larger changes in heat flows. Climate might be disrupted on a larger scale quickly, but global temperature simply can't rise that quickly. Thermodynamics precludes it.
Title: Re: Ice-free Arctic
Post by: 5to10 on February 24, 2017, 02:55:44 AM
5to10

Echoing other comments. Your original post which I queried suggested multi-degree changes for 'the earth' in just years. There is no evidence that I am aware of for that happening. In contrast the video was talking very much about local changes in the Arctic and that is a whole different story. Even the ice cores show that different things happened in different parts of Greenland. So vey localised disruptions rather than global.

Could we see some dramatic switches in local Arctic climate if sea ice crashes? Yes. The circulation changes we are seeing this year suggest those possibilities. But changes of that scale globally are a whole different kettle of fish. Needing much larger changes in heat flows. Climate might be disrupted on a larger scale quickly, but global temperature simply can't rise that quickly. Thermodynamics precludes it.

Okay.. So the biggest consequence then is disruption of local (and global?) climate, or weather patterns, or both? Thank you. I hate to come off like a fool here but I'm not as knowledgeable as most of you.

It seems important to determine the big consequences of this and snowball effects.

If weather is disrupted, agriculture could be seriously affected. Again, I'm not sure at what scale the disruption may be, so perhaps that's a false statement too.
Title: Re: Ice-free Arctic
Post by: Tigertown on February 24, 2017, 03:30:57 AM
Quote
If weather is disrupted, agriculture could be seriously affected. Again, I'm not sure at what scale the disruption may be, so perhaps that's a false statement too.

Already started, and getting worse. Several countries this year have already lost crops and land to floods. Droughts, locusts and other insects are getting worse.
 
In some places this has been going on for a while now.
www.bbc.com/news/business-32827047 (http://www.bbc.com/news/business-32827047)

As the Arctic becomes less effective as the Earth's air conditioner, things will get worse faster. The Arctic doesn't have to be completely ice free for that to happen.
Title: Re: Ice-free Arctic
Post by: Pmt111500 on February 24, 2017, 04:17:07 AM
Weather prediction from the results of climate models is just as hard as weather prediction from current initial values. The two function quite a lot differently wrt time and gridsize...  losing crops due insufficient rains (in the growing season of present time) is no doubt the biggest threat to human society (well, the floods do a good bit like tigertown said.). But the incresed moisture in the atmosphere might generate new times/areas for rains. I don't know if anyone has tried to initiate a global weather model (is there such a thing?, normally weather models handle only a fraction of the planet) with the climate model output of 2040-50s.

There's nothing in my mind that would stop the changes initiated by the Arctic melt to expand to the whole hemisphere. The intertropical convergence zone would be an atmospheric barrier, though. Clouds should be way more (in north) partially blocking the sun like ice did on clear skies and the rising tropopause allows  cloud water to cool higher up. Rains might _feel_ colder in the future.

But no, I don't know if southern india will change to a desert or if southern plains of us do the same. There are a bunch of other areas mentioned as having ill effects like the Mediterranean, here the 'medicanes' could be the beginning of new sort of weather pattern. There's all too much for one man to keep track od it all, thus the national meteorological offices...

Title: Re: Ice-free Arctic
Post by: wili on February 24, 2017, 12:34:15 PM
The truth is that we don't know what will come about in this uncontrolled massive experiment on the climate system of the only planet we've got.

However long and dark the Arctic winter is, it is not just open choppy seas that could prevent refreeze. As we have seen, transport of warm air from lower latitudes has increased, and will presumably continue to do so. There will also be ever more water vapor in the area, which will act as a blanket holding in heat. Not to mention methane...

Earlier epochs like the Eocene show quite warm ice-free Arctic conditions, and that is surely where we are headed eventually. The exact timing is the difficult thing to know for certain.
Title: Re: Ice-free Arctic
Post by: Gray-Wolf on February 24, 2017, 01:14:44 PM
In past era's of warm Arctic the changes were slow and and so the impacts had time to fully express themselves before the next set of changes began to impact.

Our warming is near instant. Our loading of the atmosphere with GHG's has been near instant. We are sat in a system that is well out of balance with the changes we should be seeing from such forcings and the changes we do see?

The last time we saw such temps/GHG forcings 2/3rds of Greenland was ice free and West Antarctica was ice free. This is the amount of excess energy that must already be within the system? Given enough time it will melt Greenland and West Antarctica but what will that 'excess energy' be turning its attentions on in the meantime?
Title: Re: Ice-free Arctic
Post by: 5to10 on February 24, 2017, 01:20:10 PM
In past era's of warm Arctic the changes were slow and and so the impacts had time to fully express themselves before the next set of changes began to impact.

Our warming is near instant. Our loading of the atmosphere with GHG's has been near instant. We are sat in a system that is well out of balance with the changes we should be seeing from such forcings and the changes we do see?

The last time we saw such temps/GHG forcings 2/3rds of Greenland was ice free and West Antarctica was ice free. This is the amount of excess energy that must already be within the system? Given enough time it will melt Greenland and West Antarctica but what will that 'excess energy' be turning its attentions on in the meantime?

It is safe to say imo, chaotic global weather even by recent standards. Massively disruptive weather, perhaps.
Title: Re: Ice-free Arctic
Post by: Tor Bejnar on February 24, 2017, 02:35:46 PM
I recall there was a study published (something like) 3 to 5 years ago* that modeled Arctic ice rebound if, magically, all the Arctic sea ice disappeared one day.  The ice returned to the (then) current volume (or extent) in about 3 years.  I'm sure they were looking primarily at albedo issues - summer heating - and winter freezing. 

Today we know more (or think we know more) about how weather is affected by ice loss, including increased humidity and storminess.  I am curious how that old model wound respond if adjusted to include these 'new' feedbacks.

_____
* - I tried looking for it (failed); it was obliquely referred to in these threads (Slow Transition) in 2014 (at least).
Title: Re: Ice-free Arctic
Post by: 5to10 on February 24, 2017, 02:43:56 PM
I recall there was a study published (something like) 3 to 5 years ago* that modeled Arctic ice rebound if, magically, all the Arctic sea ice disappeared one day.  The ice returned to the (then) current volume (or extent) in about 3 years.  I'm sure they were looking primarily at albedo issues - summer heating - and winter freezing. 

Today we know more (or think we know more) about how weather is affected by ice loss, including increased humidity and storminess.  I am curious how that old model wound respond if adjusted to include these 'new' feedbacks.

_____
* - I tried looking for it (failed); it was obliquely referred to in these threads (Slow Transition) in 2014 (at least).

Seems like you should swap the position of the word "magically" so it reads more like this, given what we know...

Quote
I recall there was a study published (something like) 3 to 5 years ago* that modeled Arctic ice rebound if all the Arctic sea ice disappeared one day.  The ice magically returned to the (then) current volume (or extent) in about 3 years.
Title: Re: Ice-free Arctic
Post by: Archimid on February 24, 2017, 03:12:04 PM
I recall there was a study published (something like) 3 to 5 years ago* that modeled Arctic ice rebound if, magically, all the Arctic sea ice disappeared one day.  The ice returned to the (then) current volume (or extent) in about 3 years.  I'm sure they were looking primarily at albedo issues - summer heating - and winter freezing. 


Ok but the volume is not disappearing magically. The volume is disappearing because a combination of forcings due to AGW are changing the relative equilibrium of the Arctic. I have seen nothing that will stop those forcing once the ice reserves are gone. Since the forcing will keep going, but there will be no reserves of ice, the arctic will warm considerably. Any model that use the historical temperatures for the Arctic winter will be very wrong.
Title: Re: Ice-free Arctic
Post by: Archimid on February 24, 2017, 03:34:30 PM
5to10

Echoing other comments. Your original post which I queried suggested multi-degree changes for 'the earth' in just years. There is no evidence that I am aware of for that happening. In contrast the video was talking very much about local changes in the Arctic and that is a whole different story. Even the ice cores show that different things happened in different parts of Greenland. So vey localised disruptions rather than global.

The bolded statement is an extraordinary claim. If there are large scale localized changes, there are good chances that there will be global changes. The Earth system is completely connected. For such claim to be true you would have to prove that the Arctic is disconnected from the rest of the climate system.

Quote
Could we see some dramatic switches in local Arctic climate if sea ice crashes? Yes. The circulation changes we are seeing this year suggest those possibilities. But changes of that scale globally are a whole different kettle of fish. Needing much larger changes in heat flows. Climate might be disrupted on a larger scale quickly, but global temperature simply can't rise that quickly. Thermodynamics precludes it.


Think of this way. In theory the whole arctic could melt today while the global temperatures remain constant. The distribution of the heat in the earth system is not a function of the global temperatures. The atmospheric and oceanic patterns can change very fast if the heat is redistributed fast enough while global temperature remain the same.
Title: Re: Ice-free Arctic
Post by: Tor Bejnar on February 24, 2017, 04:13:19 PM
One may wish this study didn't conclude what it did, but this particular computer experiment started with the understood physical reality of the Arctic, then "instantly removed" (that's magic, right?) all Arctic sea ice.  Employing the known major physical inputs and constraints, the model showed "slow" (not traditional magic where I come from) rebound, because (on an annual basis) the forces that cause ice to melt did not exceed the forces that cause water to freeze.

What I learned from hearing about that study is that the Arctic Ocean is in a relatively stable condition, ice-wise.  Or, we don't have sea ice only because ice was there ten years ago.  As greenhouse gas levels increase, the stable condition will change to one with less sea ice.  At some point, the ice will be seasonally gone, then some time later, totally gone (alligators-in-Nome, gone).  These changes may be geologically instantaneous (but not magically so :o ), but on a human scale may occur during my kids' lifetime, possibly mine. (Well, not the alligator part - not this century, anyway.)

Title: Re: Ice-free Arctic
Post by: Gray-Wolf on February 24, 2017, 04:23:24 PM
I've always held that when the Arc tic Ocean Halocline is destroyed then the type of basin that used to exist will be gone.

We would end up with an ocean like all the others on the planet and not this 'Special' ocean with its ancient deep halocline.
Title: Re: Ice-free Arctic
Post by: Archimid on February 24, 2017, 05:06:47 PM
Tor Bejnar, I wonder if this is the paper you are refering to:

Recovery mechanisms of Arctic summer sea ice


http://onlinelibrary.wiley.com/doi/10.1029/2010GL045698/full (http://onlinelibrary.wiley.com/doi/10.1029/2010GL045698/full)


If that's the paper, please look at the assumptions made on that 2011 paper and compare it to the current developments in the arctic, in particular this:

Quote
We use ECHAM5/MPI-OM to perform a climate projection for the 21st century according to the IPCC-A1B emission scenario [Nakićenović et al., 2000]. In this reference run, annual mean surface air temperature in the Arctic rises from −14°C in the 1900s to −4°C in the 2090s. Arctic sea-ice extent declines, and the Arctic Ocean is typically ice-free by the end of summer from 2070 onward (see auxiliary material; we note that the sea-ice decline here is somewhat faster than in the higher-resolution version of the model).

Note that the models they use predict that the Arctic is typically ice free by 2070. After the 2012 event, a 2070 ice free Arctic became  a pipedream. After 2016, it is obvious that the Arctic will be ice free much sooner than that. That means that whatever assumptions were used in this model were too low.

IF you can find a paper where the model runs predict an arctic sea ice before 2050 and run the same experiment I would give it more credibility. As it stands, given this year multiple anomalies, that paper is obsolete and the conclusions are not valid.

Perhaps you have a more recent paper with more realistic assumptions, but I doubt there are models out there that already digested the changes seen this year.
Title: Re: Ice-free Arctic
Post by: gerontocrat on February 24, 2017, 05:47:30 PM
I think the study in question assumed that by 2050 man-made CO2 emissions would be reduced to about zilch and CO2 concentrations would also be heading down.

Since this is just about impossible to believe, and most people who do not live in la-la-land reckon that sometime or other before 2050 positive feedbacks put the planet in a more or less permanent  hotter place then the study is about what mankind could have done, but did not.

(The USA, UK, and Australia leading the walk backwards from Paris 2015, which was not enough anyway).

End of post from  person having not a good day)
Title: Re: Ice-free Arctic
Post by: oren on February 24, 2017, 06:17:02 PM
Tor, what you mentioned is described by Chris Reynolds here. Please read. It's not all ice gone, but instead 1m of ice magically taken away. But in any case it's an interesting read.
http://dosbat.blogspot.co.il/2015/05/the-slow-transition.html?m=1 (http://dosbat.blogspot.co.il/2015/05/the-slow-transition.html?m=1)
Title: Re: Ice-free Arctic
Post by: Tor Bejnar on February 24, 2017, 08:52:21 PM
Tor Bejnar, I wonder if this is the paper you are refering to:
Recovery mechanisms of Arctic summer sea ice (http://onlinelibrary.wiley.com/doi/10.1029/2010GL045698/full)
...
Thanks - yes.  Hmmm - 6 years old!

I'm not bothered much by their optimistic projection of first ice-free summer.  We know more about humidity and southern storms.  I figure their model 'knows' something about how much heat would get into the water during the summer/autumn and how much heat would leave during the long winter.

Tor, what you mentioned is described by Chris Reynolds here. Please read. It's not all ice gone, but instead 1m of ice magically taken away. But in any case it's an interesting read.
http://dosbat.blogspot.co.il/2015/05/the-slow-transition.html?m=1 (http://dosbat.blogspot.co.il/2015/05/the-slow-transition.html?m=1)
I've read much of what Chris has written (including that post), and am influenced by it, but I don't think I'm on his bandwagon.

I've always held that when the Arctic Ocean Halocline is destroyed then the type of basin that used to exist will be gone.

We would end up with an ocean like all the others on the planet and not this 'Special' ocean with its ancient deep halocline.
This is the number one likely game-changer, in my view.  Before the halocline goes, the Arctic will behave as we've come to expect, more or less.  After the halocline goes, serious "ice-free"dom!

Back in 2012 I made a mathematically-based projection (http://neven1.typepad.com/blog/2012/10/naive-predictions-of-2013-sea-ice.html) that suggested an ice-free Arctic (the old <1M km2 meme) would arrive in 2019 or '20.  (I never revisited the method to see what it would say later.)
Title: Re: Ice-free Arctic
Post by: wili on February 24, 2017, 10:08:08 PM
possible accelerated shutdown of the Gulf Stream leading to a much chillier N. Europe?

https://www.theguardian.com/environment/2017/feb/24/drastic-cooling-north-atlantic-beyond-worst-fears-scientists-warn (https://www.theguardian.com/environment/2017/feb/24/drastic-cooling-north-atlantic-beyond-worst-fears-scientists-warn)
Title: Re: Ice-free Arctic
Post by: oren on February 24, 2017, 11:31:51 PM
I've read much of what Chris has written (including that post), and am influenced by it, but I don't think I'm on his bandwagon.
Same here. The theory is quite solid but his assumption about winter power declining only gradually is proving incorrect, which totally undermines the whole thing.
Title: Re: Ice-free Arctic
Post by: TerryM on February 25, 2017, 02:50:23 AM
I recall there was a study published (something like) 3 to 5 years ago* that modeled Arctic ice rebound if, magically, all the Arctic sea ice disappeared one day.  The ice returned to the (then) current volume (or extent) in about 3 years.  I'm sure they were looking primarily at albedo issues - summer heating - and winter freezing. 

Today we know more (or think we know more) about how weather is affected by ice loss, including increased humidity and storminess.  I am curious how that old model wound respond if adjusted to include these 'new' feedbacks.

_____
* - I tried looking for it (failed); it was obliquely referred to in these threads (Slow Transition) in 2014 (at least).


If you're still looking, I believe the study was done earlier than that. Believe it was being discussed as early as 2010, and therefor would have preceded that date.


Terry
Title: Re: Ice-free Arctic
Post by: Tor Bejnar on February 25, 2017, 02:56:00 AM
Archimid found it (see above - published in 2011).  But thanks.
Title: Re: Ice-free Arctic
Post by: TerryM on February 25, 2017, 12:03:32 PM
Archimid found it (see above - published in 2011).  But thanks.


The paper I recalled was from 2007


Climate models used to test summer Arctic sea ice recovery after either sudden artificial removal find that sea ice returns within a few years 2007 (http://onlinelibrary.wiley.com/doi/10.1002/2013JD021060/full#jgrd51102-bib-0036)


There was considerable discussion prior to 2011 with most discounting the 2007 paper.  It's possible that the later study came out to confirm or reject the earlier findings. IIRC the denier community thought S&C had nailed it while our side thought it must have been flawed.


Terry

Title: Re: Ice-free Arctic
Post by: Tor Bejnar on February 25, 2017, 02:53:18 PM
Thanks, Terry!

Impact of instantaneous sea ice removal in a coupled general circulation model (http://onlinelibrary.wiley.com/doi/10.1029/2007GL030253/abstract)
by D. Schröder and W. M. Connolley (First published: 19 July 2007)

From the abstract:
Quote
... A control run is chosen as reference experiment with greenhouse gas concentration fixed at pre-industrial conditions. Sensitivity experiments show an almost complete recovery from total removal or strong increase of sea ice after four years. ...
From the paper (section 3):
Quote
[paraphrase: December removal of ice results in almost instantaneous ice coverage because it's cold and the water is cold too]... A longer-lasting impact is achieved by removing the sea ice in summer. This is because no sea ice can build up during summer, and if no sea ice is present the reduced surface albedo causes an increase in ocean temperature (up to 2.5 K for the area mean in the Arctic and 1 K in the Antarctic at a depth of 5 m) which delays freezing in the next autumn. The impact of seasonality found when sea ice is removed differs from the study of Wu et al. [1996], in which the strongest effect occurs when the sea ice is removed at its maximum coverage (late winter). The disagreement can be explained by the different models. Wu et al. [1996] have applied an atmospheric sea ice model with a one layer ocean beneath sea ice. Thus, they couldn't resolve the heating process of the mixed-layer ocean, which is the dominating effect in our study. ...
Title: Re: Ice-free Arctic
Post by: Csnavywx on February 25, 2017, 08:10:17 PM
possible accelerated shutdown of the Gulf Stream leading to a much chillier N. Europe?

https://www.theguardian.com/environment/2017/feb/24/drastic-cooling-north-atlantic-beyond-worst-fears-scientists-warn (https://www.theguardian.com/environment/2017/feb/24/drastic-cooling-north-atlantic-beyond-worst-fears-scientists-warn)

The paper the article links to is $$$. The interesting thing is that the higher the model skill in the study, the higher the chance of deep ocean convection collapse in the North Atlantic sub-polar gyre. Note that this doesn't include any meltwater input (and they call for models that can do this).
Title: Re: Ice-free Arctic
Post by: Shared Humanity on February 25, 2017, 09:49:13 PM
I've read much of what Chris has written (including that post), and am influenced by it, but I don't think I'm on his bandwagon.
Same here. The theory is quite solid but his assumption about winter power declining only gradually is proving incorrect, which totally undermines the whole thing.

Winter power may very well be dropping precipitously but this ridiculously warm winter north of 80 degrees is still averaging about -20C. Even with the complete destruction of the halocline which I am certain will occur, sea ice will form in the dark polar night. It just won't be the sea ice we are used to and a seasonally ice free state will persist.

The real issue is how the global climate will be impacted by this new polar ocean environment. It will be an unending series of weather disasters stretching into perpetuity.

I believe the Beaufort provides a hint of what the freeze will look like. It was completely ice free at the end of the melt season. There has been no import of thicker MYI this freeze season and the halocline, due to persistent storms, has been damaged if not destroyed. Never the less, there is 1.5 meters thin, highly mobile FYI that covers the Beaufort.
Title: Re: Ice-free Arctic
Post by: Archimid on February 26, 2017, 02:52:54 AM
Thanks, Terry!

Impact of instantaneous sea ice removal in a coupled general circulation model (http://onlinelibrary.wiley.com/doi/10.1029/2007GL030253/abstract)
by D. Schröder and W. M. Connolley (First published: 19 July 2007)

Let me see if I get this straight. They removed the ice in December, the ice grows back really fast. They remove the ice in September, it grows back. Excellent. Then this happens

Quote
The preceding experiments were somewhat unrealistic because although the ice was removed, the ocean was still in a state compatible with ice cover. Hence, in the following experiments the ocean temperature will be modified to examine an ice-free situation in the real world where an ice anomaly is connected with an ocean heat anomaly.

So what changes they make?

Quote
Based on these findings two further sensitivity experiments are performed in which the initial global sea ice is removed and the ocean temperature of the uppermost 200 m (10 model levels) is artificially increased to a minimum value of 3°C on March 1st and September 1st, respectively. The initial salinity and ocean circulation remain the same as in the Ctrl run.

To me the bolded statement ruins the experiment. Salinity and circulation might be more important than temperature. Not to mention waves. The fact that they don't mention the starting air temperatures worry me even more. The ocean might be 3C warmer, but the atmosphere will be much warmer than that, as we have previewed this year.


Title: Re: Ice-free Arctic
Post by: Glenn Tamblyn on February 26, 2017, 10:06:31 AM
5to10

"If weather is disrupted, agriculture could be seriously affected. Again, I'm not sure at what scale the disruption may be, so perhaps that's a false statement too."

This is perhaps the key predictive uncertainty on a sub-decadal timescale. Can changes in weather systems around the Arctic propagate outwards to produce chaotic weather changes on a global scale. Very hard to say.

Thermodynamically it is harder to imagine substantial weather variability changes propagating over much of the planet as a regular feature of annual weather over short timescales. The basic heat engine of the climate system doesn't let it be completely chaotic. That's a positive.

However, agriculture can be very sensitive to short term weather excursions. Hit rice plants with a heat wave that is too high for even a few hours and the male parts of the plant become sterile - no rice from that plant. So key agricultural regions can get hit hard as we saw in Russia in 2010.

Thus if Arctic weather chaos can propagate far enough it can potentially produce bad individual events. Localised famines for example. Bad, but the world can cope with them, in the short term. Its called food aid.

How far off are structural food supply problems, permanent famines? That's harder but I suspect several decades.

Which is a very bleak prospect. Years of sporadic famine, then eventually, no light at the end of the tunnel, just entrenched famine.  But I think it will take more than a few years of the first before the later arrives. More like a small number of decades.
Title: Re: Ice-free Arctic
Post by: 5to10 on February 26, 2017, 12:56:35 PM
5to10

"If weather is disrupted, agriculture could be seriously affected. Again, I'm not sure at what scale the disruption may be, so perhaps that's a false statement too."

This is perhaps the key predictive uncertainty on a sub-decadal timescale. Can changes in weather systems around the Arctic propagate outwards to produce chaotic weather changes on a global scale. Very hard to say.

Thermodynamically it is harder to imagine substantial weather variability changes propagating over much of the planet as a regular feature of annual weather over short timescales. The basic heat engine of the climate system doesn't let it be completely chaotic. That's a positive.

However, agriculture can be very sensitive to short term weather excursions. Hit rice plants with a heat wave that is too high for even a few hours and the male parts of the plant become sterile - no rice from that plant. So key agricultural regions can get hit hard as we saw in Russia in 2010.

Thus if Arctic weather chaos can propagate far enough it can potentially produce bad individual events. Localised famines for example. Bad, but the world can cope with them, in the short term. Its called food aid.

How far off are structural food supply problems, permanent famines? That's harder but I suspect several decades.

Which is a very bleak prospect. Years of sporadic famine, then eventually, no light at the end of the tunnel, just entrenched famine.  But I think it will take more than a few years of the first before the later arrives. More like a small number of decades.

Yes, It seems logical that this is the biggest threat re: collapse in the near future. All it will take is one really bad year.
Title: Re: Ice-free Arctic
Post by: magnamentis on February 26, 2017, 04:47:53 PM
5to10

"If weather is disrupted, agriculture could be seriously affected. Again, I'm not sure at what scale the disruption may be, so perhaps that's a false statement too."

This is perhaps the key predictive uncertainty on a sub-decadal timescale. Can changes in weather systems around the Arctic propagate outwards to produce chaotic weather changes on a global scale. Very hard to say.

Thermodynamically it is harder to imagine substantial weather variability changes propagating over much of the planet as a regular feature of annual weather over short timescales. The basic heat engine of the climate system doesn't let it be completely chaotic. That's a positive.

However, agriculture can be very sensitive to short term weather excursions. Hit rice plants with a heat wave that is too high for even a few hours and the male parts of the plant become sterile - no rice from that plant. So key agricultural regions can get hit hard as we saw in Russia in 2010.

Thus if Arctic weather chaos can propagate far enough it can potentially produce bad individual events. Localised famines for example. Bad, but the world can cope with them, in the short term. Its called food aid.

How far off are structural food supply problems, permanent famines? That's harder but I suspect several decades.

Which is a very bleak prospect. Years of sporadic famine, then eventually, no light at the end of the tunnel, just entrenched famine.  But I think it will take more than a few years of the first before the later arrives. More like a small number of decades.

Yes, It seems logical that this is the biggest threat re: collapse in the near future. All it will take is one really bad year.

i get the point and agree to the meaning and intention while the biggest threat IMO is Sea Level Rise, why?

because it cannot be compensated and corrected or held in check by any means. a city under water is a lost city and arable land under water is no arable land anymore, while drying up zones can be watered with water taken from the ocean and de-salinated by osmosis with energy produced by the sun or other sustainable means.

don't wanna start a discussion about this, it's just an example to show the difference between:

a) possible to correct or lower the consequence by no matter how far fetches means

b) not possible to correct and/or reduce the consequences by no means at all.

hope i was able to make my point, else jump in and make up for my lake of english skills

cheers
Title: Re: Ice-free Arctic
Post by: 5to10 on February 26, 2017, 05:01:03 PM
Is it more likely that sea level rise will be the culprit before extreme, chaotic weather that is rearing its head faster already? Don't know about that... Seems agriculture failure due to weather is the most present danger. I don't see how sea level could rise fast enough to become an issue before that.
Title: Re: Ice-free Arctic
Post by: TerryM on February 26, 2017, 06:54:31 PM
i get the point and agree to the meaning and intention while the biggest threat IMO is Sea Level Rise, why?

because it cannot be compensated and corrected or held in check by any means. a city under water is a lost city and arable land under water is no arable land anymore, while drying up zones can be watered with water taken from the ocean and de-salinated by osmosis with energy produced by the sun or other sustainable means.

don't wanna start a discussion about this, it's just an example to show the difference between:

a) possible to correct or lower the consequence by no matter how far fetches means

b) not possible to correct and/or reduce the consequences by no means at all.

hope i was able to make my point, else jump in and make up for my lake of english skills

cheers


No problem with your English, but perhaps there is a difference in land use where you are located.


In the States & Canada most of the shoreline lost whatever agricultural potential it might have had decades ago when housing or resort facilities took up much of the most productive and scenic land. Ocean vistas sell for inflated prices and building up delta regions has been going on for centuries.


When SLR damages North America, the damage will be to infrastructure as opposed to agriculture. Port facilities, transportation hubs, urbanized structures, these will be devastated before agricultural losses become apparent.
Drought/flood cycles and unpredictable weather will play havoc with agriculture long before SLR needs to be entered into the equation here in North America. The situation may be different elsewhere.


Terry
Title: Re: Ice-free Arctic
Post by: magnamentis on February 26, 2017, 07:02:07 PM
i get the point and agree to the meaning and intention while the biggest threat IMO is Sea Level Rise, why?

because it cannot be compensated and corrected or held in check by any means. a city under water is a lost city and arable land under water is no arable land anymore, while drying up zones can be watered with water taken from the ocean and de-salinated by osmosis with energy produced by the sun or other sustainable means.

don't wanna start a discussion about this, it's just an example to show the difference between:

a) possible to correct or lower the consequence by no matter how far fetches means

b) not possible to correct and/or reduce the consequences by no means at all.

hope i was able to make my point, else jump in and make up for my lake of english skills

cheers


No problem with your English, but perhaps there is a difference in land use where you are located.


In the States & Canada most of the shoreline lost whatever agricultural potential it might have had decades ago when housing or resort facilities took up much of the most productive and scenic land. Ocean vistas sell for inflated prices and building up delta regions has been going on for centuries.


When SLR damages North America, the damage will be to infrastructure as opposed to agriculture. Port facilities, transportation hubs, urbanized structures, these will be devastated before agricultural losses become apparent.
Drought/flood cycles and unpredictable weather will play havoc with agriculture long before SLR needs to be entered into the equation here in North America. The situation may be different elsewhere.


Terry

sure, i get your point of view, thanks for elaborating :-)

i'ts very often that different peoples views and opinions depend on different priorities depending where we all are coming from and/or how and from which angle we are looking at things.

this, IMHO is the main and best reason why it's so important to exchange thought with an open mind so to not see things too narrow minded which again is the reason why i so much appreciate all the different input that will add to the never ending (at least in our life time LOL) learning curve.

i wish you and your folks a pleasant reminder of the weekend
Title: Re: Ice-free Arctic
Post by: oren on February 26, 2017, 07:07:46 PM
Food shortage will mostly affect poor people in poor countries, initially (as happened in 2010), while sea level rise will affect all low lying areas and a lot of infrastructure built near the shore in rich countries: harbors, power plants, desalination plants, and lots more. Sea level is a much stronger impact, although slower in coming.
Bear in mind sea level rise affects food - a lot of production happens in low-lying river deltas.
Title: Re: Ice-free Arctic
Post by: TerryM on February 26, 2017, 09:49:59 PM
i wish you and your folks a pleasant reminder of the weekend


Thanks!


Oren brings up the important role that wealth, both individually and nationally, will have as things continue to break. With no one willing, or perhaps able, to pay for the repairs or simply required maintenance, the future can look bleak.


When North Americans bemoan the loss Miami's white beaches, the Vietnamese may well hunger for delta grown rice. SLR is final, with Bangladesh, the Maldives ,and others set to lose so much of the land they need, that migration or genocide are the only alternatives available.


Under ASLR conditions the wealthy countries will need whatever resources they still possess to prop up their own failing infrastructure, just at the time that the have nots will require a massive influx of food and money just to stay afloat. (unintended) If Trump's followers consider today's levels of immigration to be problematical, wait until peoples land is literally washing out from beneath their feet.


Debt forgiveness now, while there is still some fluidity in the vaults of the wealthy, is essential. Squeezing those who will soon need these same resources for their own survival is neither morally correct nor fiscally sound. The moral argument seems self evident, while the fiscal imperative to either feed starving neighbors, or spend more trying to keep them out, indicates that early intervention might prove less expensive.


Three years ago Cuba had a $32B debt to Russia. Today that debt is gone. Cuba had been unable to make payments for years and Russia had a claim on whatever future assets Cuba might amass. Cuba, looking forward, will probably have more need of these Billions than a resurgent Russia.


If Germany, France, in fact the whole of industrialized Europe, would forgive Greece, Italy and other southern European states their debt, these states might have more of the resiliency needed in the coming decades. Similar arrangements are needed between the US and some central and south American nations. With the Monroe Doctrine the US took responsibility for all of the Americas, yet at present many are finding themselves insolvent and with huge debts to American banks.


Walls, fences, and coastal defenses, are expensive, inhumane, and ineffective. Historically only small island nations have had short lived success at keeping the barbarian's from the gate.
While the billions extant will never attain European or North American lifestyles, the excesses we waste could maintain many in livable conditions.


Had anyone thought to provide sufficient bread to those starving in Syria, perhaps millions would not now be banging on European doors. Had much of the middle east not suddenly lost it's infrastructure, their citizens would still be at home plotting football strategies. If NAFTA had not beggared Mexican corn farmers, their sons and daughters would be taking siesta under the tropical sun, rather than huddling in cold Chicago alleyways.


Wow, sorry for my extended revelry. The point I was trying to make is that it might prove less expensive to forgive debt at a national level, than to fight to "preserve our way of life" when starving people head in our direction.
Sea Level Rise is coming, and it won't be pretty whether viewed from under tattered tarpaulins or silver chandeliers.


Terry
Title: Re: Ice-free Arctic
Post by: magnamentis on February 26, 2017, 10:21:07 PM
no no no.... don't be sorry, that is all spot on and +1 and it's key to so many things that go wrong.

they prefer to sell guns for billions and justify their army with the profit ( i know it's too simple) instead of giving their surplus of milk, tomatoes and bread which they sell in africa under the local production price, for free to those who just need food and perhaps a tent.

sometimes i honestly think that i will end up on one of those islands, you know, those where the polynesian seafarers went to to wait for their days to end.
Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 08, 2018, 12:13:56 AM
Can anyone help me detail positive feedbacks amplified by the new arctic state?

Albedos
Methane release
oceanic warming/Water vapour
downward radiations increasing related to temperature inversion


And any negatives... if there are any worth speaking of.

A 2011 study estimated that the albedo effect of an ice-free arctic for a month in late summer would increase from the current forcing of 0.11 watts per meter squared (W/m-2) to 0.30 W/m-2.  Using current estimates of climate sensitivity, that would lead to a global temperature increase of 0.15 degrees C. Here's the abstract from the study:

Quote
A simple method for estimating the global radiative forcing caused by the sea ice–albedo feedback in the Arctic is presented. It is based on observations of cloud cover, sea ice concentration, and top-of-atmosphere broadband albedo. The method does not rely on any sort of climate model, making the assumptions and approximations clearly visible and understandable and allowing them to be easily changed. Results show that the globally and annually averaged radiative forcing caused by the observed loss of sea ice in the Arctic between 1979 and 2007 is approximately 0.1 W m−2; a complete removal of Arctic sea ice results in a forcing of about 0.7 W m−2, while a more realistic ice-free summer scenario (no ice for 1 month and decreased ice at all other times of the year) results in a forcing of about 0.3 W m−2, similar to present-day anthropogenic forcing caused by halocarbons. The potential for changes in cloud cover as a result of the changes in sea ice makes the evaluation of the actual forcing that may be realized quite uncertain since such changes could overwhelm the forcing caused by the sea ice loss itself, if the cloudiness increases in the summertime.

The study can be read here:  http://onlinelibrary.wiley.com/doi/10.1029/2011JD015804/full (http://onlinelibrary.wiley.com/doi/10.1029/2011JD015804/full)

Title: Re: Ice-free Arctic
Post by: Archimid on March 08, 2018, 01:37:47 AM
Quote
Using current estimates of climate sensitivity, that would lead to a global temperature increase of 0.15 degrees C.

 If the global, annual temperature is increased by .15C, how much will be the local, monthly temperature increase in the arctic?

How does that local increase in temperature and humidity affects atmospheric and ocean currents?


Then you start october with 0 ice and much higher temperarures than normal. What is the most ice the Arctic has grown in a year? 

How thick will that ice be by april of the next year?

How quick will the thin, very low extent ice reach 0 again? August? July?

Rinse and repeat.

Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 08, 2018, 01:54:46 AM
For a good article outlining some of the possible impacts of the loss of Arctic see ice, go here: https://www.nature.com/news/arctic-2-0-what-happens-after-all-the-ice-goes-1.21431 (https://www.nature.com/news/arctic-2-0-what-happens-after-all-the-ice-goes-1.21431)

In the article, they note that the loss of sea ice is not irreversible, provided we stop warming the planet:

Quote
If the future of the Arctic seems dire, there is one source of optimism: summer sea ice will return whenever the planet cools down again. “It’s not this irreversible process,” Stroeve says. “You could bring it back even if you lose it all.”

Unlike land-based ice sheets, which wax and wane over millennia and lag behind climate changes by similar spans, sea ice will regrow as soon as summer temperatures get cold enough. But identifying the exact threshold at which sea ice will return is tricky, says Dirk Notz, a sea-ice researcher at the Max Planck Institute for Meteorology in Hamburg, Germany. On the basis of model projections, researchers suggest that the threshold hovers around 450 parts per million (p.p.m.) — some 50 p.p.m. higher than today. But greenhouse-gas concentrations are not the only factor that affects ice regrowth; it also depends on how long the region has been ice-free in summer, which determines how much heat can build up in the Arctic Ocean.

Notz and his colleagues studied the interplay between greenhouse gases and ocean temperature with a global climate model8. They increased CO2 from pre-industrial concentrations of 280 p.p.m. to 1,100 p.p.m. — a bit more than the 1,000 p.p.m. projected by 2100 if no major action is taken to curtail greenhouse-gas emissions. Then they left it at those levels for millennia.

This obliterated both winter and summer sea ice, and allowed the ocean to warm up. The researchers then reduced CO2 concentrations to levels at which summer ice should have returned, but it did not regrow until the ocean had a chance to cool off, which took centuries.
Title: Re: Ice-free Arctic
Post by: Archimid on March 08, 2018, 02:15:10 AM
So no answer to my questions. Just avoidance. Maybe the problem is my english. Nah. I think you understood the questions fine.  If you didn't I could ask them again. Let me know.

Title: Re: Ice-free Arctic
Post by: liefde on March 08, 2018, 12:00:16 PM
I have stopped worrying about the subsea methane bomb - and decided waiting for news from paleo climatologists,
How can the changes observed more recently in a three decade period be conclusive?
Dr. Shakhova: For the permafrost, three decades is not a huge period of time, because the processes, the consequences of which we are studying right now and have to deal with, started long long ago. This was triggered by natural warming associated with replacement of the cold climate epoch with the warm interglacial period and followed by permafrost inundation by sea water. Scientists agree that submerged permafrost would eventually start degrading, but how soon and at what pace this degradation would occur became the major point of disagreement between them.
It was suggested by some scientists that subsea permafrost would keep its integrity for millennia, which means that in the areas submerged less than 1000 years ago (as we investigated in our study) it should not have occurred yet. Our study proved that not only has it already occurred, but it has been progressing to higher rates, which have almost doubled since this degradation started.
It is most likely that we are now dealing with the consequences of when natural warming is enhanced with anthropogenic warming and together they are accelerating the pace of natural processes. This appears to be continuing the processes of permafrost degradation at levels that we have never observed before."
http://envisionation.co.uk/index.php/nick-breeze/203-subsea-permafrost-on-east-siberian-arctic-shelf-now-in-accelerated-decline
Title: Re: Ice-free Arctic
Post by: liefde on March 08, 2018, 12:07:55 PM
In the article, they note that the loss of sea ice is not irreversible, provided we stop warming the planet
This was before they knew about the ~9 year lag of T peak after release. Now, we just learned that 2017 showed 2% more CO2 emissions than the year before that. It isn't slowing down, i.e. global T is going to continue to rise for at least the coming 9 years..
Title: Re: Ice-free Arctic
Post by: liefde on March 08, 2018, 12:16:20 PM
Quote
Using current estimates of climate sensitivity, that would lead to a global temperature increase of 0.15 degrees C.
If the global, annual temperature is increased by .15C, how much will be the local, monthly temperature increase in the arctic?
As it stands, current models (predominantly GFS) use precisely double global T for everything North of 80 degrees. So global increase of .15C would mean Arctic Circle increase of .30C. And as such that would be exponentially significant with more T rise, as +80N is partly *cause* of the feedbacks. A global rise of 2 degrees C, would mean another +4 C for +80N, and so forth.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fsites.uci.edu%2Fzlabe%2Ffiles%2F2018%2F03%2FT925_Arctic_NCEP_OctFeb2018_composite.gif&hash=98a30fd479d75e8f860b198528fde606)
Title: Re: Ice-free Arctic
Post by: Archimid on March 08, 2018, 12:35:20 PM
liefde, that seems too low. Global anual temperatures since 2016 are about 1C higher than 20th global anual temperatures average.  In your graph you present a 6 month average temp local to the Arctic that is 5C above average.

An anual global increase of 1C lead to a local semianual increase of 5C.

The monthly increase should be even higher.

The locality of changes is vital. A world that is evenly warming should present a lot less climate change than a world that is unevenly warming, like ours is.
Title: Re: Ice-free Arctic
Post by: Gray-Wolf on March 08, 2018, 01:07:54 PM
This " if we stop warming the planet" thing? As I understand it NASA is telling us that up to 50% of the warming is being masked by the flip side of our polluting ( global dimming) so if we suddenly stopped polluting we would have both the CO2 'lag' plus a near doubling it the warming we've seen once the particulates/sulphates drop out....
I think the forcing this would impart to the Arctic would wrought changes is was very hard to reverse ( methane/CO2 from natural sources?)?
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 08, 2018, 04:32:47 PM
This " if we stop warming the planet" thing? As I understand it NASA is telling us that up to 50% of the warming is being masked by the flip side of our polluting ( global dimming) so if we suddenly stopped polluting we would have both the CO2 'lag' plus a near doubling it the warming we've seen once the particulates/sulphates drop out....
I think the forcing this would impart to the Arctic would wrought changes is was very hard to reverse ( methane/CO2 from natural sources?)?

That may be true, if we stop polluting.  But what if we stop polluting and emitting carbon dioxide?  If pollution is cooling the globe by half what CO2 is warming (according to NASA), then temperatures should drop, if both are ceased simultaneously.
Title: Re: Ice-free Arctic
Post by: Andreas T on March 08, 2018, 05:06:56 PM
The difference is that CO2 stays in the atmosphere longer than particulates. So if we stop adding CO2 into the atmosphere it stays nearly what it is now for longer, whereas particulates concentration and their dimming of the atmosphere starts to drop much more quickly.
Title: Re: Ice-free Arctic
Post by: Gray-Wolf on March 08, 2018, 05:12:38 PM
This " if we stop warming the planet" thing? As I understand it NASA is telling us that up to 50% of the warming is being masked by the flip side of our polluting ( global dimming) so if we suddenly stopped polluting we would have both the CO2 'lag' plus a near doubling it the warming we've seen once the particulates/sulphates drop out....
I think the forcing this would impart to the Arctic would wrought changes is was very hard to reverse ( methane/CO2 from natural sources?)?

That may be true, if we stop polluting.  But what if we stop polluting and emitting carbon dioxide?  If pollution is cooling the globe by half what CO2 is warming (according to NASA), then temperatures should drop, if both are ceased simultaneously.
There is a lag ( around 30 years?) for the CO2 currently up there to have its full impacts felt so we would have this slow warming but for the first 7 years we'd be finding out just how much of the warming potential has been being 'masked' by the 'flip side' of our polluting?

As I understand it we know how much solar is hitting the top of the atmosphere but the amount getting down to the surface ( to be absorbed and then re-radiated in the infra red for the GHG's to  interact with?) is significantly less due to the interference with sulphates/particulates.

The measure is via the 'pan evaporation rate' which is basically a pan of water and we measure to see how much has been evaporated by the incoming solar ( bounced out of the pan due to the energy imparted?).

I saw a BBC documentary on the discovery of our 'Dimming' over our high polluting decades? I think it was studies in both Israel and Australia that were finding this 'drop' in pan evaporation and eventually discovered each others research which confirmed something amiss was going on?

Sadly 'our' pollution though dirty was not anything like as dirty as the Chinese pollution ( and wood burning across Asia?) due to the coals used? I think the Chinese get a lot of high soot/high sulphur coal so their pollution per tonne burned will be far greater than ours was and so be more impactful?

Because of the high impact on Urban societies China is in a headlong dash to reduce the pollution with a combination of cleaning up emmisions and utilising renewable over coal fired power stations.

Unlike us they do not need to develop the technology as we , in the west, were well on with our clean air technologies so the Chinese can instantly, and effectively, cut their dirty pollution by buying /copying our technologies?

So we were well on our way to our dimming being dealt with when China very rapidly hoyed it back up to high levels again .

Now , just as quickly, we are seeing dimming again dropping away. Unlike our period the new solar getting through has far more CO2/water vapour to encounter once re-radiated so the warming spike we saw through the 80's and 90's ( as our 'clean air acts took impact) will be far less than the warming spike we are now beginning to see develop?

I am of the opinion that the switch of the Pacific 'naturals' was aided by the sudden increase in solar again reaching the surface as the Chinese efforts to clean up their act, from the mid noughties onward, began showing an ever increasing impact?

I'd go even further and say the imbalance between tropical Pacific/Atlantic that saw impacts including the high shear environment over the Caribbean ( limiting Hurricanes since 05') the record trade winds ( turning over the ocean and constantly burying the heat being accumulated at the surface....the so called 'pause') were all driven by the rapid increase in dirty pollution from the 90's and into the noughties from across Asia and impacting the Pacific basin far more than others (via the particulate loading which was then washed out before reaching America /Atlantic basin ).

The rapid decline in especially the particulate loading has impacted the Pacific very quickly and so has allowed the tropical basins to again find parity and hence lessening the shear in the tropical Atlantic and allowing the resumption in the formation big Hurricanes ( no longer having high shear constantly knock their tops off or fetch large amounts of Saharan dust into the Caribbean!).

Hurricanes are huge heat engines and the ones in the Atlantic recurve up into the Arctic via either Baffin or Fram so their resumption could drive changes on the Atlantic side of the basin in late melt season?
Title: Re: Ice-free Arctic
Post by: Gray-Wolf on March 08, 2018, 05:33:15 PM
The difference is that CO2 stays in the atmosphere longer than particulates. So if we stop adding CO2 into the atmosphere it stays nearly what it is now for longer, whereas particulates concentration and their dimming of the atmosphere starts to drop much more quickly.

Thanks Andreas!

Yes the 'lifetime' of CO2 in the atmosphere will keep us around current levels , once fully activated and the 'dimming' removed, for a significant period ( over 100yrs?) and that heat will continue to act on the planet.

If just 'ice melt' then areas uncovered will have their own 'hibernating' carbon cycle preserved below and so this will again join the current carbon cycle. The permafrost will continue melting and the biological process continue to reanimate leading to further expansions in the carbon cycle.

So even if we stop all our carbon emissions we will have to wait for their full impacts on the planet to be felt before we can think about GHG levels falling?

We have very much 'lit the blue touch paper' and Mother Nature will now play her role which has the potential to be far greater than our impacts?

Let us put it another way. By 2010 we were at the same temp/GHG forcing as last seen over 120,000yrs ago. At that time west Antarctica was ice free. So , over time, we should see west Antarctica now become ice free and not only raise sea levels but also reintroduce the carbon cycle buried beneath that ice. This will , in its turn ,melt more of East Antarctica which apart from raising Sea Levels will uncover part of it's hibernating carbon cycle which will enter back into the system so warming us some more which melts even more of Antarctica....rinse and repeat.

So without touching upon the northern permafrosts we can see that our impacts have already set us on a course to have Mother Nature release GHG's

Though I loathe the idea I can see no other course of action than actively reducing our GHG loading before we find reinforcing impacts occurring more vigorously!
Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 08, 2018, 07:05:26 PM
Quote
Using current estimates of climate sensitivity, that would lead to a global temperature increase of 0.15 degrees C.

 If the global, annual temperature is increased by .15C, how much will be the local, monthly temperature increase in the arctic?

How does that local increase in temperature and humidity affects atmospheric and ocean currents?


Then you start october with 0 ice and much higher temperarures than normal. What is the most ice the Arctic has grown in a year? 

How thick will that ice be by april of the next year?

How quick will the thin, very low extent ice reach 0 again? August? July?

Rinse and repeat.

Arcmid,

I post a response.  Initially, the ice will regrow and then melt again in summer.  Eventually, if the Arctic warms enough, the Arctic will be ice free for more and more of the year.  However, when the Arctic cools, the ice will grow back.

Rinse and repeat.
Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 08, 2018, 08:00:39 PM
It's very difficult to predict how the atmosphere will respond to climate change, which makes it even more difficult to make predictions of regional responses to climate change.  That's because some of the responses will be offset.  For example, there is evidence that when anthropogenic aerosols are reduced in the atmosphere, organic aerosols increase.  Will it be enough to offset that warming effect, at least partially?  We don't know.

For an ice free arctic, some of the effects are predictable, such as the increase in the ice-albedo affect.  Some can only be speculated about, such as changes to the atmospheric circulation.  Part of the reason for this is that global warming is expected to shift the Hadley cells poleward, however, melt of the Arctic sea ice is expected to oppose this effect.  Here's an article about the issue:  http://onlinelibrary.wiley.com/doi/10.1002/2017GL076096/full (http://onlinelibrary.wiley.com/doi/10.1002/2017GL076096/full)  The key conclusion is:
Quote
The warming of sea surface temperatures (SSTs) and the direct radiative impact of CO2 have been shown to favor the poleward shift of midlatitude circulation (Grise & Polvani, 2014). However, in the Northern Hemisphere (NH), this process might be opposed by the loss of Arctic sea ice and the associated polar amplification of global warming (e.g., Blackport & Kushner, 2017; Harvey et al., 2015; Shaw et al., 2016). By analyzing the intermodel spread in the future projections from the Fifth Phase of the Coupled Model Intercomparison Project (CMIP5), evidence of this “tug-of-war” between tropical and polar forcing has been identified for the future response in the latitude of the North Atlantic jet (Barnes & Polvani, 2015), the strength of midlatitude storm tracks (Harvey et al., 2014), and the speed of midlatitude westerlies (Manzini et al., 2014; Zappa & Shepherd, 2017).

And we haven't considered changes to the ocean currents.  They may respond to changes in atmospheric pressure or wind patterns over time, and in the long run, they carry most of the heat from the tropics toward the poles.

That's why regional predictions of responses to climate change are difficult.  Estimating global temperature responses is easier because it's based on an overall response to multiple forcings over a long time.
Title: Re: Ice-free Arctic
Post by: Alexander555 on March 08, 2018, 08:53:48 PM
This " if we stop warming the planet" thing? As I understand it NASA is telling us that up to 50% of the warming is being masked by the flip side of our polluting ( global dimming) so if we suddenly stopped polluting we would have both the CO2 'lag' plus a near doubling it the warming we've seen once the particulates/sulphates drop out....
I think the forcing this would impart to the Arctic would wrought changes is was very hard to reverse ( methane/CO2 from natural sources?)?

That may be true, if we stop polluting.  But what if we stop polluting and emitting carbon dioxide?  If pollution is cooling the globe by half what CO2 is warming (according to NASA), then temperatures should drop, if both are ceased simultaneously.


Where would we be without the industrial revolution and mass population growth ? Probably in the next ice age. So the people in Canada are lucky we have some climate change.  But that makes no diffrence at the moment, because we are going to add more greenhouse gases for a long time. Because they still keep this planet running. And i think you can not put a number on how much warmer it will get with an arctic ice free for a month, like 0,15 degree C. Because it will continue to go up gradualy. Why would it stop at 0,15 degree C. That's not how are oceans function. There are no sources on this planet that can cool it down more than today. It will just add more heat.
Title: Re: Ice-free Arctic
Post by: Archimid on March 08, 2018, 09:43:59 PM

I post a response.  Initially, the ice will regrow and then melt again in summer.


Yes, but:

 1. Initial conditions in October will be very different from initial conditions of the past. To begin with there won be a giant slab of ice keeping the waves down and the humidity locked in the oceans. The water will be very warm from all the incoming radiation. The atmosphere will be very warm too.

2. Before ice can form all the extra heat and humidity must be vented and the waves calmed. That means that refreezing will begin late and from 0.

3. Winter temperatures are already crashing. After A BOE Arctic growth is bound to be anemic.

4. Come the melting season of the following year the ice will be thinner than ever, with a record low extent.

5. This means that the year following  the first ice-free year will be ice free again but much sooner, gathering more heat than ever.

6. See 1.

Quote
Eventually, if the Arctic warms enough, the Arctic will be ice free for more and more of the year.


Yep

Quote
However, when the Arctic cools, the ice will grow back.


And there is not reason for it to cool until GHG levels in the atmosphere are significantly lower. It can be centuries or millenia. Eventuall, regardless of CO2, milankovitch cycles guarantee that it will return.
Title: Re: Ice-free Arctic
Post by: Archimid on March 08, 2018, 09:54:34 PM
That's why regional predictions of responses to climate change are difficult.  Estimating global temperature responses is easier because it's based on an overall response to multiple forcings over a long time.

Yes they are difficult but that is the only way to asses the risk. Global temperatures hide the risk. By presenting the impact of Arctic albedo changes in terms of global temperatures the risk is hidden. By understanding the local changes the risk is revealed.
Title: Re: Ice-free Arctic
Post by: Gray-Wolf on March 09, 2018, 10:40:40 AM
I think we might all profit from discovering just what a unique beast the Arctic Ocean is compared to all other world oceans?

Once we've found out just how special , and why, we have to accept that the more blue ocean events we see the more it become just like all other oceans.

At present it is an ocean sorted for ice cover so layered in a unique way ( compared to all other oceans) and that it took ice ages to bring that depth of stratification?

We are moving to a position that would leave the Ocean being broadly similar to the southern ocean around Antarctica but underlain by huge amounts of heat from the Atlantic inputs ( and Pacific but the Atlantic bottom waters are the most extensive?).

So we may well see ice reform if we cool the planet but the old Arctic Ocean will be lost and the behaviours of the 'new Arctic Ocean' different.

We are watching the destruction ,not just of the ice, but of a unique Ocean.
Title: Re: Ice-free Arctic
Post by: gerontocrat on March 09, 2018, 02:20:35 PM
I am with Gray-Wolf on this - we are seeing the destruction of an irreplaceable unique 14 million km2 wonder of the world .(But we have the David Attenborough / BBC Natural History Unit videos in HD, so why should it matter ?  ***)

But when - will we see, are we seeing, very rapid change ?
So I had a think.

At this time, maximum, there are about 2 million km2 of open water where once there was ice.
Every year the peripheral seas melt out completely, and freeze again every year.
Are the number of days the seas are ice-free increasing as sea-ice declines?

I looked at NSIDC Regional data from their spreadsheet. I chose to define "ice-free" as less than 5% of the maximum (sort of) in each sea, as that is ice-free for all practical purposes. Ignoring pockets of ice stuck in corners seemed a good idea.

I divided the regional seas into "peripheral" and CAB arbitrarily. I think I needed a thrid ategory of just one - Hudson Bay (largely landlocked, relatively shallow, low salinity (big river catchments)

Two graphs below summarise the answers. And the answer is - ice-free days in the peripheral seas increase over time but relatively slowly.
In the CAB, the Kara, Laptev and East-Siberian ice-free days are starting to emerge (in last 10 years) from zero ice-free days.

HUDSON BAY ice-free days up from about 30 in 1979 to 80+ by now. Note the recent dip - increased snow in Eastern Canada?

So, I could find no evidence that a sea going ice-free would not be able to re-freeze.
The number of ice-free days is (relatively) gradually increasing over time.

I use the satellite record as my time frame - because one has to start somewhere. My guess is we will see the end of a 45-50 year long tipping point sometime in the next 5 to 10 years, i.e. a blue ocean September between 2024 and 2029.

50 years is an immensely short period of time for such a profound change. We have seen and are seeing very rapid change. After that there will only be technical arguments about how long the ice-free season will be and how much ice will fall off Greenland..

*** HD Videos - It is called sarcasm.

Title: Re: Ice-free Arctic
Post by: Archimid on March 09, 2018, 03:10:31 PM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fiwantsomeproof.com%2Fextimg%2Fsiv_annual_max_loss_and_ice_remaining.png&hash=abd6be9e6aae50f91aecf6b77a2ce574)

I think that once the volume max hits about 17-19 we are done.  This year looks like we might get an uptick, so I think the apocalypse has been postponed one more year. I can even accept that max volume loss might slow down  some and give us a few more years, maybe even a decade. However, the next moderate to strong el niño we are toast.

 Chris Reynolds' "The slow transition" scenario seems to be most likely scenario.  A theory with such a  counter intuitive name must have very high chances of being right.
Title: Re: Ice-free Arctic
Post by: oren on March 09, 2018, 03:17:03 PM
gerontocrat, I think you can dig more insights by charting the number of days not just with nearly ice-free but also with partial ice cover - 90% and less, 50% and less, 25% and less. I recently made the calculation for the Chukchi And there are some clear trends there.
Here's a gif which to me really shows the process of becoming seasonally ice free - earlier thaw, deeper melt-out, later refreeze - and a (not very clear) chart I'd made trying to quantify the trends.
Title: Re: Ice-free Arctic
Post by: gerontocrat on March 09, 2018, 05:09:51 PM
gerontocrat, I think you can dig more insights by charting the number of days not just with nearly ice-free but also with partial ice cover - 90% and less, 50% and less, 25% and less. I recently made the calculation for the Chukchi And there are some clear trends there.
Here's a gif which to me really shows the process of becoming seasonally ice free - earlier thaw, deeper melt-out, later refreeze - and a (not very clear) chart I'd made trying to quantify the trends.

Hi Oren,

Yup - I really like that gif, already swallowed into my PC. ps: Which gif-maker do you use. I suppose I have to bite the bullet sometime.

The little analysis I did had a simple objective - to see if there is evidence from the historical record of an Ice-Free Arctic just around the corner. I could find no dramatic acceleration in ice-free days at the periphery - merely the remorseless downwards trend now also nibbling at the edges of the CAB itself. I expect to see a lot of dramatic posts in the months ahead that may need calming down.

A General Theory Everything of Relativity the Arctic

Wouldn't it be nice to have a general Arctic database of everything. I've got data on CO2 emission and CO2 concentrations,, air temperatures, sea ice extent and area, sea level rise, insolation (but not a good database), etc etc etc all over the place, with a few connections.

But if I think about a further issue - ice-extent loss and effect on insolation, then I have to start from scratch again. The thought is, the insolation season is centred around the summer solstice. The melting season is centred around early to mid-September, nearly three months later. So for insolation early melt is far more significant than early extent gain. The analysis for each sea would have to combine daily extent with the insolation W/m2 for that day at that latitude to calculate trends in potential insolation gain. Maybe some surprises in the answer?

With a generalised database one could imagine just asking the question. It is the sort of thing A-Team and his cohorts are up to? (One clapped out PC won't hack it)



Title: Re: Ice-free Arctic
Post by: Daniel B. on March 09, 2018, 05:25:45 PM
I am with gerontocrat on this.  The largest ice growth in the Arctic occurred following the summers with the two lowest minima (2012 and 2007).  Indeed, the winter ice growth has a strong [second order] inverse relationship with the previous summer's minimum.  Conversely, summer ice loss has a relatively poor relationship to the previous winter's ice maximum.  Additionally, the ice gained and lost each season has increased considerably in recent years; the average summer ice loss over the past decade has increased 13% from the previous three decades, while the winter ice gain has increased 12%.  Overall, the Arctic sea ice is declining, but at a slow rate, and not a rapid decline.
Title: Re: Ice-free Arctic
Post by: Archimid on March 09, 2018, 05:39:34 PM
Gerontocrat,  Have you looked at Tealights work at 

https://sites.google.com/site/cryospherecomputing/warming-potential/graphs

I believe he has your answer(more questions?) for albedo warming potential.
Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 09, 2018, 10:27:16 PM

I post a response.  Initially, the ice will regrow and then melt again in summer.


Yes, but:

 1. Initial conditions in October will be very different from initial conditions of the past. To begin with there won be a giant slab of ice keeping the waves down and the humidity locked in the oceans. The water will be very warm from all the incoming radiation. The atmosphere will be very warm too.

2. Before ice can form all the extra heat and humidity must be vented and the waves calmed. That means that refreezing will begin late and from 0.

3. Winter temperatures are already crashing. After A BOE Arctic growth is bound to be anemic.

4. Come the melting season of the following year the ice will be thinner than ever, with a record low extent.

5. This means that the year following  the first ice-free year will be ice free again but much sooner, gathering more heat than ever.

6. See 1.

Quote
Eventually, if the Arctic warms enough, the Arctic will be ice free for more and more of the year.


Yep

Quote
However, when the Arctic cools, the ice will grow back.


And there is not reason for it to cool until GHG levels in the atmosphere are significantly lower. It can be centuries or millenia. Eventuall, regardless of CO2, milankovitch cycles guarantee that it will return.

The arctic gets really, really cold in winter.  Even when it's warmer than usual, it's still below freezing.  That's why most scientists who study the arctic don't think we'll see ice-free (less than 1,000,000 square km of ice) Septembers until the 2050s at the earliest.  And even then, if we reduce our emissions, the Arctic will refreeze every winter and the loss of sea ice will plateau.

Quote
This paper addresses the specter of a September ice-free Arctic in the 21st century using newly available simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5). We find that large spread in the projected timing of the September ice-free Arctic in 30 CMIP5 models is associated at least as much with different atmospheric model components as with initial conditions. Here we reduce the spread in the timing of an ice-free state using two different approaches for the 30 CMIP5 models: (i) model selection based on the ability to reproduce the observed sea ice climatology and variability since 1979 and (ii) constrained estimation based on the strong and persistent relationship between present and future sea ice conditions. Results from the two approaches show good agreement. Under a high-emission scenario both approaches project that September ice extent will drop to ∼1.7 million km2 in the mid 2040s and reach the ice-free state (defined as 1 million km2) in 2054–2058. Under a medium-mitigation scenario, both approaches project a decrease to ∼1.7 million km2 in the early 2060s, followed by a leveling off in the ice extent.

Full article in the Proceedings of the National Academies of Science (2013) here: http://www.pnas.org/content/110/31/12571 (http://www.pnas.org/content/110/31/12571)

And here's a more recent article about the duration of ice-free portions of the Arctic during summer:  https://pubag.nal.usda.gov/catalog/5405017 (https://pubag.nal.usda.gov/catalog/5405017).  Here's the abstract:

Quote
Global warming and continued reduction in sea ice cover will result in longer open water duration in the Arctic, which is important for the shipping industry, marine mammals, and other components of the regional ecosystem. In this study we assess the length of open water duration in the Alaskan Arctic over the next few decades using the set of latest coupled climate models (CMIP5). The Alaskan Arctic, including the Chukchi and the Beaufort Sea, has been a major region of summer sea ice retreat since 2007. Thirty five climate models from CMIP5 are evaluated and twelve are selected for composite projections based on their historical simulation performance. In the regions north of the Bering Strait (north of 70° N), future open-water duration shifts from a current 3–4months to a projected near 5months by 2040 based on the mean of the twelve selected climate models. There is considerable north–south gradient in projected durations. Open water duration is about 1month shorter along the same latitudes in the Beaufort Sea compared with that in the Chukchi Sea. Uncertainty is generally ±1month estimated from the range of model results. Open-water duration in the Alaskan Arctic expands quickly in these models over the next decades which will impact regional economic access and potentially alter ecosystems. Yet the northern Alaskan Arctic from January through May will remain sea ice covered into the second half of the century due to normal lack of sunlight.

Title: Re: Ice-free Arctic
Post by: Archimid on March 10, 2018, 02:15:14 AM
First let me be very clear. Your post and my post are talking about two very different things.

you talked about:

When will the Arctic be sea ice free in the summer for the first time?

I talked about:

What happens after the first ice free Arctic, if anything?


So lets examine your claims:

Quote
The arctic gets really, really cold in winter.  Even when it's warmer than usual, it's still below freezing.  That's why most scientists who study the arctic don't think we'll see ice-free (less than 1,000,000 square km of ice) Septembers until the 2050s at the earliest.

And that is precisely why they are so wrong. The Arctic winter is already warming. It is warming very fast. This year we had local temperatures above 0 at the North Pole in February. The data set that best captures the winter warming is DMI's 2m temperatures north of 80.

http://ocean.dmi.dk/arctic/meant80n.uk.php

I suggest you examine winter temperature anomalies for the last 2 years and compare them to the rest of the dataset. The warming is obvious. This highly anomalous  but consistent warming at the Arctic happened exactly at the same time as global temperatures jumped to the record levels we have now. Projections are that the globe will warm much more.

Worst of all the warming experienced in the arctic over the last two years is not directly because of CO2. The warming is a result of hot humid air from the Pacific and Atlantic entering the Arctic and causing havoc on the ice. This is due to disturbances in the atmosphere caused by changes in sea ice and the global jet streams. The waviness of the jet streams forces warm southern air into the Arctic creating a redistribution of heat towards the Arctic. That is not in the models because it didn't work that way before.

Quote
And even then, if we reduce our emissions, the Arctic will refreeze every winter and the loss of sea ice will plateau.

The ice will plateau only if global temperatures plateau. For that we have to significantly reduce emissions very fast. As of right now, that is just a pipe dream, specially with the effort of many despicable people attempting to hide the risks.


About the two papers you posted

Wonderful papers made by serious scientist, but they are wrong. They both ignore the changes in the jet streams that a reduced Arctic sea ice (among other things) produces.

https://link.springer.com/article/10.1007/s00382-016-3367-1
Quote
The Arctic is currently undergoing drastic changes in climate, largely thought to be due to so-called ‘Arctic amplification’, whereby local feedbacks enhance global warming. Recently, a number of observational and modelling studies have questioned what the implications of this change in Arctic sea ice extent might be for weather in Northern Hemisphere midlatitudes, and in particular whether recent extremely cold winters such as 2009/10 might be consistent with an influence from observed Arctic sea ice decline. However, the proposed mechanisms for these links have not been consistently demonstrated. In a uniquely comprehensive cross-season and cross-model study, we show that the CMIP5 models provide no support for a relationship between declining Arctic sea ice and a negative NAM, or between declining Barents–Kara sea ice and cold European temperatures. The lack of evidence for the proposed links is consistent with studies that report a low signal-to-noise ratio in these relationships. These results imply that, whilst links may exist between declining sea ice and extreme cold weather events in the Northern Hemisphere, the CMIP5 model experiments do not show this to be a leading order effect in the long-term. We argue that this is likely due to a combination of the limitations of the CMIP5 models and an indication of other important long-term influences on Northern Hemisphere climate.


So as you see, the events we are just recently witnessing are not properly acknowledged in the models used in what you posted. Climate scientists were expecting unknown unknowns. This is one of them.

Edit:

I wanted to add the following, but posted by error.

Quote
In the regions north of the Bering Strait (north of 70° N), future open-water duration shifts from a current 3–4months to a projected near 5months by 2040 based on the mean of the twelve selected climate models

That is happening right now. See the Bering graph attached.




Title: Re: Ice-free Arctic
Post by: oren on March 10, 2018, 10:55:34 AM
Archimid, note that "north of Bering Strait" is actually the Chukchi Sea, not the Bering. And if you check my Chukchi gif and graph from upthread, you will see indeed that the seasons are lengthening as we speak and in a much higher rate than predicted. From 3-4 months to only "nearly 5 months" by 2040? I am certain the model is vastly underestimating.
Title: Re: Ice-free Arctic
Post by: gerontocrat on March 10, 2018, 11:06:31 AM
Gerontocrat,  Have you looked at Tealights work at 

https://sites.google.com/site/cryospherecomputing/warming-potential/graphs

I believe he has your answer(more questions?) for albedo warming potential.

Wonderful, Archimid. and a what a lovely piece of work by Tealight and Nico Sun. Indeed he does, answers and questions .

I compared 2016 with 2012.

In the 2012 Arctic spring, sea ice was comparatively high, very high, compared with other years in the 2010's. Low albedo warming potential. Then the big collapse and up goes albedo warming potential   - but.

In 2016, sea ice loss started early, but then became sort of average, with sea ice minimum hundreds of thousands of km2 greater than 2012. And despite that 2016 cumulative albedo warming potential for the year is higher by far than 2012.

i.e. low winter maxima and early melt is the most effective way to heat up the Arctic ocean.

The two graphs say it all.
Q.E.D.
Title: Re: Ice-free Arctic
Post by: gerontocrat on March 10, 2018, 11:51:25 AM
JAXA is on holiday today - so a bit of spare time to rummage around the data.

Attached is a graph showing the average sea ice extent of the last 365 days for the last 2+ years. Yes, it looks backwards. As each new day is added, the value that day one year ago is taken off, and the new total is divided by 365.

So, on 8th March 218 extent was 190,000 km2 less than on 8th March 2017. The total for the year goes down by 190,000 but is then divided by 365. The annual average drops by just over 500 km2.
I like the graph, as it shows the slow decline in sea ice.

I put in a trendline, and had to go to the power of five to get a decent fit. It shows a big drop in the next 6 months or so. Is it possible? To my surprise - yes. 2017 ended up with a minimum of about 4.5 million, perhaps at least 500,000 km2 more than most people (including me) expected earlier in the season.

If melt is strong this year, extent could easily end up 750,000 km2 or more less than in 2017, meaning average annual extent could go down at 2,000 km2 per day or even a bit more. But that still means a long way to go to an ice-free Arctic.
Title: Re: Ice-free Arctic
Post by: gerontocrat on March 10, 2018, 05:10:07 PM
ALBEDO ARCTIC OCEAN WARMING POTENTIAL

Two posts above I compared 2016 with 2012 to show how early melt was so much more important than a September record low  when looking at albedo effects on warming of the arctic ocean .

I forgot to add the graph. So here it is, courtesy of NSIDC, 2016 red, 2012 dotted dark green. It is extent, but for demonstration purposes OK though area would be better. I also attach again the cumulative albedo warming potential graph from Tealight to reinforce the correlation.
Title: Re: Ice-free Arctic
Post by: Gray-Wolf on March 10, 2018, 09:07:05 PM
Oh I am now worrying about low solar impacts esp. the high pressure over the basin/Greenland that we saw last time!

The 2012 HP over Greenland led to that melt at summit if was so well positioned and brought us our record smashing  year in the basin.

I know we would need sympathetic naturals as well but I am sure that Low solar is the key to the trick working?

Over the period from half way down the cycle, to half way back up the cycle, saw the naturals have a few bites at the cherry that have not been repeated since half way up the cycle , peak solar to half way back down.

Now we are in that 'danger zone' again so how many seasons before the naturals assist enough to let the 'magic key' work again?

Have we now altered that naturals so much that it would have to be an even rarer conflagration of of them for the solar 'magic key' to work or are we to expect one of the next 5 years or so to throw us another record smashing Arctic/Greenland year?.... and a step closer to ice free or even a Blue Ocean event......
Title: Re: Ice-free Arctic
Post by: Alexander555 on March 10, 2018, 09:44:51 PM
Oh I am now worrying about low solar impacts esp. the high pressure over the basin/Greenland that we saw last time!

The 2012 HP over Greenland led to that melt at summit if was so well positioned and brought us our record smashing  year in the basin.

I know we would need sympathetic naturals as well but I am sure that Low solar is the key to the trick working?

Over the period from half way down the cycle, to half way back up the cycle, saw the naturals have a few bites at the cherry that have not been repeated since half way up the cycle , peak solar to half way back down.

Now we are in that 'danger zone' again so how many seasons before the naturals assist enough to let the 'magic key' work again?

Have we now altered that naturals so much that it would have to be an even rarer conflagration of of them for the solar 'magic key' to work or are we to expect one of the next 5 years or so to throw us another record smashing Arctic/Greenland year?.... and a step closer to ice free or even a Blue Ocean event......


That danger zone, low solar. How do you explain that ? If i understand it correct, it's a little warmer at the solar high. And a little colder at the solar low. So is it that little extra heat during the solar high that steps in , in some way. Does it build up a couple years maybe, before it cools down a little on his way to the solar high.
Title: Re: Ice-free Arctic
Post by: Archimid on March 10, 2018, 11:40:11 PM
Oren, thanks for the correction. You are right. The Northern Alaska is the Chukchi/Beaufort not the Bering Sea as I said. Maybe since it is still March and the Bering refuses to cooperate my claim will be correct on the opposite side (April/May). Nice animation BTW.

Gerontocrat I agree that it is unlikely to happen this year. In my way of seeing things, ice volume is higher than last year.  There is a mild la niña going, I think that helps in general terms.  The big thing to watch is the Bering. That little dip in the Chukchi when the Bering was really low had disaster written all over it. I'm glad it recovered. I think it will recover again and grow for a bit.  If it doesn't melt will start real early in the chukchi
Title: Re: Ice-free Arctic
Post by: gerontocrat on March 18, 2018, 02:46:06 PM
There has been a lot of stuff about increased snowfall in the freezing thread, some about the season to come from this winter's large snow fall and some looking further ahead, all saying that the increased snow on the ground will inhibit sea ice melt. i.e. -ve feedback

I've been looking at another consequence of increased snowfall with potential longer-term impacts on AGW and therefore the potential for an ice-free Arctic. Increased snowfall may well accelerate breakdown of permafrost and release of methane and CO2. i.e. +ve feedback. Two examples below.

Example 1
https://www.sciencedaily.com/releases/2016/03/160302204625.htm

Quote
How permafrost thawing affects vegetation, carbon cycle
Study focuses on Toolik Lake area of Alaska's North Slope
Date: March 2, 2016
Source: University of Delaware
Summary:Scientists are exploring how the thawing of permafrost affects vegetation and the carbon cycle in the Toolik Lake area of Alaska's North Slope.

Climate models predict 25-50 percent more precipitation in the Arctic region by the end of the century, mostly as fall and winter snow. However, extra snow can also mean extra moisture during warmer seasons like spring and summer.

Snow fence experiment
During fieldwork, the scientists used an existing snow fence that had been in place for 18 years to explore what changes in average snow accumulation might mean for the Toolik Lake area.

Typical winter snowfall depth in the area is about one foot. The snow fence, which stands approximately 9 feet high by 200 feet long, was built perpendicular to the wind direction so that snowdrifts would form behind the fence. This allowed the researchers to mimic various snowfall accumulations for the region, from below normal to average to much higher levels of winter precipitation.

Snow blanket means longer growing season for plants
As they reviewed the data, the researchers discovered that in areas with increased winter precipitation, the ground didn't freeze as deeply because the snow acted like a blanket, keeping the ground warmer than normal.

Their findings showed that higher snow accumulations resulted in increased soil temperatures and a deeper thawing of the permafrost, which, in turn, resulted in increased microbial activity, increased melting depth and more water content in the soil that led to increased production of methane and more plant growth.

In areas with reduced snow accumulation, however, the soil acted as a methane sink because of enhanced activity of methane-oxidizing bacteria.

When the snow melted, scientists noted a longer growing season for plants and shrubs. In areas with higher snow, the soil also collapsed when the ice that was occupying the soil's pore space melted, causing depressions in the ground.

"It affected more than just the amount of methane produced, it changed the landscape and the types of plants that grew there. We started seeing woody plants -- dwarf trees like birch and other shrubs -- instead of just moss, lichens and grass."

Example 2
http://iopscience.iop.org/article/10.1088/1748-9326/11/9/091004/pdf

Quote
Abstract
The dramatic shrinkage of Arctic sea ice is one of the starkest symptoms of global warming, with
potentially severe and far-reaching impacts on arctic marine and terrestrial ecology (Postet al 2013 Science 341 519–24) and northern hemisphere climate (Screen et al 2015 Environ. Res. Lett. 10 084006).
In their recent article, Alexeev et al (2016 Environ. Res. Lett. 11 074022) highlight another,
and unexpected, consequence of Arctic sea ice retreat: the thinning of lake ice in northern Alaska. This is attributed to early winter‘ocean effect’snowfall which insulates lake surfaces and inhibits the formation of deep lake ice. Lake ice thinning has important consequences for Arctic lake hydrology, biology and permafrost degradation......

....they show that impacts from an open Arctic Ocean in autumn are both direct, through
increased air temperature and precipitation, and indirect, through inhibiting bedfast ice formation in lakes leading to localised permafrost degradation and talik formation
Title: Re: Ice-free Arctic
Post by: crandles on March 18, 2018, 05:16:25 PM
Rather late but in addition to
S. Tietsche et al 2011 Recovery mechanisms of Arctic summer sea ice

there was also
D. Schröder  & W. M. Connolley 2007
Impact of instantaneous sea ice removal in a coupled general circulation model

https://wmconnolley.wordpress.com/2015/10/18/sea-ice-the-triumph-of-the-william/

So as you see, the events we are just recently witnessing are not properly acknowledged in the models used in what you posted. Climate scientists were expecting unknown unknowns. This is one of them.

I accept that there are effects not properly acknowledged in the models. However that doesn't demonstrate that those effects are important. If you look at the bets I made in the stoat link and manage to follow it back you would see I used a gompertz shape decline in sea ice. I bet on there being less ice than the gompertz fit.


Thanks - yes.  Hmmm - 6 years old!

I'm not bothered much by their optimistic projection of first ice-free summer. 

Despite the gompertz shape suggesting declining rates of sea ice loss, and despite thinking I had good terms on those bets, I lost those bets.

I suggest the conclusion that should be drawn is that the data since 2011 does not suggest things  are proceeding worse than a linear trend. I also suggest almost all of the scientists have stuck to their maybe 2030-2050 sort of timetable in spite of all the alarmist projections here and elsewhere and they unlike some here appear correct to have stuck to that sort of timeframe. The alarmist projections have failed badly since 2011 / 2012.

So rather than saying
"I'm not bothered much by their optimistic projection of first ice-free summer.",

I think the data would suggest we should instead be saying something more like

"Their [model/scientists] projections seem to be holding up as we receive more data making them seem realistic."
Title: Re: Ice-free Arctic
Post by: oren on March 18, 2018, 05:51:08 PM
2012 was below the trend, and no wonder projections made at the time were overly pessimistic for sea ice loss. It still doesn't mean the models are correct. I would be highly surprised if first "ice free" arctic in its common definition will occur after 2030.
Note: I realize that the trend is subject to change as more data comes in, and that any projections based on the trend can easily fail. And I acknowledge I am not an ice scientist and have no qualifications in making my prediction above. So feel free to ignore.
Title: Re: Ice-free Arctic
Post by: crandles on March 18, 2018, 06:51:19 PM
I believe my bets were made after 2011, so after 2012 I thought I was in a really strong position.

But yes we can see that now. That why I wasn't claiming the gompertz shape was too pessimistic but just the data since 2011 didn't support an OMG it is going to be worse than trend/what scientist think/...
Title: Re: Ice-free Arctic
Post by: crandles on March 18, 2018, 07:03:52 PM
It still doesn't mean the models are correct. I would be highly surprised if first "ice free" arctic in its common definition will occur after 2030.

I suspect 12 years is a bit long a period to bet on. Would you be willing to bet (with William Connolley?) on whether ice extent would be half way down to 1m km^2 in 6 years time? if not that, some different figure?
Title: Re: Ice-free Arctic
Post by: oren on March 18, 2018, 07:15:04 PM
It still doesn't mean the models are correct. I would be highly surprised if first "ice free" arctic in its common definition will occur after 2030.

I suspect 12 years is a bit long a period to bet on. Would you be willing to bet (with William Connolley?) on whether ice extent would be half way down to 1m km^2 in 6 years time? if not that, some different figure?
As a trader by profession, I am not averse to risk taking  but I'd rather keep my head clear for incoming science. Being in a bet does strange things to your psychology.
Title: Re: Ice-free Arctic
Post by: Alexander555 on March 18, 2018, 07:17:24 PM
I would take the bet.
Title: Re: Ice-free Arctic
Post by: crandles on March 18, 2018, 07:45:17 PM
As a trader by profession, I am not averse to risk taking  but I'd rather keep my head clear for incoming science. Being in a bet does strange things to your psychology.

Fair enough, it can do. On the other hand if you don't attempt to lay out a bet, 6 years later it is hard to remember what you thought and therefore struggle to know how situation has changed. Think there may be an argument there for a few £1 bets.  ;)

William Connolley seems more likely to offer to bet in excess of £1000 which I am not prepared to do. So asked over on Stoat.

If Alexander wants £10 to £50 pounds, I will take it (subject to agreeing terms and exchanging suitable info) for a bit of fun. If Alexander wants more then better agreeing terms with WC.
Title: Re: Ice-free Arctic
Post by: Alexander555 on March 18, 2018, 07:50:40 PM
If you look at the pic, at the diffrences between the years close to each other.

1979 = 16 800 km3
1981 = 12 600 km3
difference = 4200 km3

1992 = 14 800 km3
1995 = 11 200 km3
difference = 3600 km3

2004 = 9800 km3
2007 = 6500 km3
difference = 3300 km3

2012 = 3600 km3
2014 = 6800 km3
difference = 3200 km3

In nominal terms it's going down a little. But as a % of it's total body, it's going up fast. And we are now a little above 4000 km3, at minimum. The temperature continued to go up. A lot of the ice is fractured. I would put it before 2025. 1 million km2 at 1 m thick
Title: Re: Ice-free Arctic
Post by: crandles on March 18, 2018, 08:01:39 PM
I'll wait to hear how much you want to bet before starting to suggest to much detail on terms.

Think WC and I would prefer it to be extent but I may be prepared to change to volume. I would also prefer to use average of 3 or so years.
Title: Re: Ice-free Arctic
Post by: Alexander555 on March 18, 2018, 08:11:04 PM
You have a company where you can bet on it ?
Title: Re: Ice-free Arctic
Post by: crandles on March 18, 2018, 08:23:16 PM
For £100 bets William has paid up to me, and I have paid up to him. So for that level I think we should just trust each other. There are some sites where money goes to winners charity. Intrade closed down and other betting sites don't seem interested.

If you want a larger amount but only if there is some trusted third party, then I could take a look to see if I can find someone bet would likely be with WC not me. A contract could be drawn up if that provides any reassurance.
Title: Re: Ice-free Arctic
Post by: Alexander555 on March 18, 2018, 08:40:13 PM
I would just do it for fun, small amounts.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 19, 2018, 05:54:02 PM
2012 was below the trend, and no wonder projections made at the time were overly pessimistic for sea ice loss. It still doesn't mean the models are correct. I would be highly surprised if first "ice free" arctic in its common definition will occur after 2030.
Note: I realize that the trend is subject to change as more data comes in, and that any projections based on the trend can easily fail. And I acknowledge I am not an ice scientist and have no qualifications in making my prediction above. So feel free to ignore.

Many of the projections at that time assumed a second order decline in sea ice, such that the 1 million sq km mark would be breached in 2018.  Using a simple linear trend, that would not occur to sometime around 2054.  After an additional five years, the data aligns more closely to a third order decline, which may or may not reach an ice-free condition.
Title: Re: Ice-free Arctic
Post by: Archimid on March 19, 2018, 07:05:51 PM
***Hit Post instead of Preview, my apologies. edit finished***

Let's try a different approach using Maximum volume.
Every year volume is lost during the melting season. These are the stats for yearly volume loss:

Avgerage Volume Loss   16.89
Median Volume Loss           16.613
Maximum Volume Loss   19.693
Minimum Volume  Loss   13.925
SD   1.263269588

If Maximum Volume ever reaches 16.89 chances are that year the Arctic will be ice free using the literal definition of ice free. When is that maximum number reached? The following table uses the linear trend of 1990 and every year since the year 2000 to predict when the maximum volume hits the average volume loss. Maximum volume loss intercept with maximum volume in the second column.

intercept   16.89   19.7
1990    2105    2081
2000    2068    2051
2001    2067    2050
2002    2064    2048
2003    2062    2047
2004    2057    2043
2005    2055    2041
2006    2051    2038
2007    2046    2034
2008    2045    2033
2009    2045    2033
2010    2044    2032
2011    2041    2030
2012    2040    2029
2013    2040    2029
2014    2039    2029
2015    2040    2029
2016    2040    2029
2017    2038    2028


Can anyone else see the trend of the trend lines?

Yet Daniel B. claims that this must be ignored because the trend will reverse and stabilize? Why should it?

There is no sign in the data that the maximum volume trend is stabilizing.

Then there is physics. Is the Arctic warming or cooling? It is warming of course. Do we expect it to keep warming or to cool?  It is expected to keep warming.  Then why an Arctic with less ice and more heat should stabilize?

Daniel B. what phenomena are you counting on to decrease the trend? Saying that there will be ice in the arctic in 50-100 years is a extraordinary claim which requires extraordinary evidence.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 19, 2018, 07:56:15 PM
No, you have the burden of proof backwards.  Yours is the extraordinary claim, and therefore requires extraordinary evidence.  A simple extrapolation beyond that which is known, does not meet that test.
Title: Re: Ice-free Arctic
Post by: Wherestheice on March 19, 2018, 08:43:37 PM
Arctic ice is doomed. IMO there will be a BOE sometime in the next decade.... sooner or later
Title: Re: Ice-free Arctic
Post by: Archimid on March 19, 2018, 08:50:11 PM
To Crandles:


See the first Image attached. The Volume Gain represents the gain from Volume Minimum to Volume Maximum since 2007. The Volume Gain for the last 11 years was above the average for the whole data set, so it represents the historical best case scenario.

At the start of the freezing season, after the first BOE the volume of ice in the Arctic is 0. If you take best case scenario past growth as an estimate of Maximum Volume at the end of the freezing season, then the average ice volume in the Arctic will be below the average ice loss.

AvgVolGain        17.68545455
MedVolGain       17.726
MaxVolGain       19.659
MinVolGain      14.872
Variance            1.723272273

AvgVolLoss               18.091
MedVolLoss                18.235
MaxVolLoss                19.693
MinVolLoss                 16.243
Variance               1.2755444

Using the historical record alone and removing all context, the year following the first BOE will also have a BOE. If we start talking about global warming, arctic amplification, the delay of the freezing season after a BOE, waves, things get real ugly real fast.
Title: Re: Ice-free Arctic
Post by: Iceismylife on March 19, 2018, 09:00:02 PM
No, you have the burden of proof backwards.  Yours is the extraordinary claim, and therefore requires extraordinary evidence.  A simple extrapolation beyond that which is known, does not meet that test.
Put some ice in a pan on the stove.  Turn on the heat. Watch it melt.  A simple extraction of ice loss will get you a result that is reasonably accurate.

yearly ice loss is going up.  yearly maximum ice volume is going down.

Put a high loss year with a low volume year and we are ice free now.
Title: Re: Ice-free Arctic
Post by: Archimid on March 19, 2018, 09:23:04 PM
Quote
Put a high loss year with a low volume year and we are ice free now.

The record low Maximum was last year at 20.782. The two record high loss years are 2010 at 16.962 and 2012 at 19.963.  That's a difference of .819.  The standard deviation for ice loss is 1.26. An ice free Arctic can happen any year now, with increasing probabilities every year that goes by.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 19, 2018, 09:40:05 PM
No, you have the burden of proof backwards.  Yours is the extraordinary claim, and therefore requires extraordinary evidence.  A simple extrapolation beyond that which is known, does not meet that test.
Put some ice in a pan on the stove.  Turn on the heat. Watch it melt.  A simple extraction of ice loss will get you a result that is reasonably accurate.

yearly ice loss is going up.  yearly maximum ice volume is going down.

Put a high loss year with a low volume year and we are ice free now.

Sorry, but burden of proof requires more than boiling an ice cube on the stove and extrapolating that to the Arctic.
Title: Re: Ice-free Arctic
Post by: Archimid on March 19, 2018, 09:41:03 PM
Quote
Yours is the extraordinary claim, and therefore requires extraordinary evidence.

Funny. You think that my claim is extraordinary because it is scary. I think your claim is extraordinary because it defies the data and the evidence.

Your claim requires a turn around of global temperatures, arctic temperatures, a turn around of ice content and ice content trends. Even then you have no physical mechanism for such turn around. None. Zero. Zilch. Nada. Only insults and pseudo skeptic statements.  You are right, because what I say is too scary to be true. LOL.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 19, 2018, 11:01:30 PM
Quote
Yours is the extraordinary claim, and therefore requires extraordinary evidence.

Funny. You think that my claim is extraordinary because it is scary. I think your claim is extraordinary because it defies the data and the evidence.

Your claim requires a turn around of global temperatures, arctic temperatures, a turn around of ice content and ice content trends. Even then you have no physical mechanism for such turn around. None. Zero. Zilch. Nada. Only insults and pseudo skeptic statements.  You are right, because what I say is too scary to be true. LOL.

What are you talking about?  In the situation you describe, the ice would expand, not shrink.  No one (that I am aware) has many any such projections or described any physical mechanism for such an occurrence.  Scary is what people use, when they do not sufficient science to back their claims.  Please stick to science, and not insults. 
Title: Re: Ice-free Arctic
Post by: Archimid on March 19, 2018, 11:14:43 PM
Quote
What are you talking about?
Sea ice volume is going down. The data is clear. Temperatures are going up. The data is clear. Ice conditions are deteriorating, that is also clear.  Yet you claim that the volume loss will stop and even reverse. You make that claim without any statistic or physics to justify a reversal of the trends. That's an extraordinary claim because it goes against all trends and it is not properly justified. You need extraordinary evidence to justify a trend reversal.

The only reason my claim is extraordinary is because it seems scary. My claim is that the trends that we have seen will continue.

Will there be a hiatus that may temporarily slow the trends? Maybe, if we are lucky. but after the hiatus we get the next jump step. I don't see how the ice will survive it.

That an alleged man of science can't even acknowledge the risk but instead plays down the risk at every possible turn says everything about your claim.
Title: Re: Ice-free Arctic
Post by: oren on March 19, 2018, 11:18:53 PM
I recommend letting nature take its course, rather than feeding into this argument. Any bad year now can finish the ice off.  2012 wasn't forecasted using these "conservative/skeptic" methods, and neither will the next one. No way all years will be lucky until 2054, probabilities don't work like that.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 20, 2018, 12:19:22 AM
I recommend letting nature take its course, rather than feeding into this argument. Any bad year now can finish the ice off.  2012 wasn't forecasted using these "conservative/skeptic" methods, and neither will the next one. No way all years will be lucky until 2054, probabilities don't work like that.

Sounds reasonable.  If we get more bad years, the ice has little chance of surviving until 2054.  Contrarily if we get more good years, then an ice-free Arctic would be pushed out further.  If we continue on our current trajectory, and nothing changes, then the target is 2054 +/- 5 years.  The probability of a new record low occurring in the near future are high.  But every new record, is followed by renewed growth.  The odds of back to back records are low.
Title: Re: Ice-free Arctic
Post by: Gray-Wolf on March 20, 2018, 12:49:20 AM
1 Cal to warm 1cm cubed of water to 1c isn't it?
70 Cals to melt 1cm cubed of ice?

But how much to take it from minus 40c to freezing?

And how much to raise it from minus 20c to freezing?

If winter isn't 'chilling' the ice as much as it used to then 'normal' summer heat packs more of a punch insofar as normal amounts of energy to help with that '70 cal' state change?

One year soon we will see just how much that matters!
Title: Re: Ice-free Arctic
Post by: oren on March 20, 2018, 01:12:20 AM
I recommend letting nature take its course, rather than feeding into this argument. Any bad year now can finish the ice off.  2012 wasn't forecasted using these "conservative/skeptic" methods, and neither will the next one. No way all years will be lucky until 2054, probabilities don't work like that.
Sounds reasonable.  If we get more bad years, the ice has little chance of surviving until 2054.  Contrarily if we get more good years, then an ice-free Arctic would be pushed out further.  If we continue on our current trajectory, and nothing changes, then the target is 2054 +/- 5 years.  The probability of a new record low occurring in the near future are high.  But every new record, is followed by renewed growth.  The odds of back to back records are low.
Please don't try to twist my words as if we agree on this. I believe an "ice-free" arctic minimum will first occur before 2030.
Title: Re: Ice-free Arctic
Post by: Shared Humanity on March 20, 2018, 01:43:23 AM
I recommend letting nature take its course, rather than feeding into this argument. Any bad year now can finish the ice off.  2012 wasn't forecasted using these "conservative/skeptic" methods, and neither will the next one. No way all years will be lucky until 2054, probabilities don't work like that.
Sounds reasonable.  If we get more bad years, the ice has little chance of surviving until 2054.  Contrarily if we get more good years, then an ice-free Arctic would be pushed out further.  If we continue on our current trajectory, and nothing changes, then the target is 2054 +/- 5 years.  The probability of a new record low occurring in the near future are high.  But every new record, is followed by renewed growth.  The odds of back to back records are low.
Please don't try to twist my words as if we agree on this. I believe an "ice-free" arctic minimum will first occur before 2030.

I only get to read this guys comments when someone quotes him as I set him on ignore a while ago.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 20, 2018, 02:33:44 PM
I recommend letting nature take its course, rather than feeding into this argument. Any bad year now can finish the ice off.  2012 wasn't forecasted using these "conservative/skeptic" methods, and neither will the next one. No way all years will be lucky until 2054, probabilities don't work like that.
Sounds reasonable.  If we get more bad years, the ice has little chance of surviving until 2054.  Contrarily if we get more good years, then an ice-free Arctic would be pushed out further.  If we continue on our current trajectory, and nothing changes, then the target is 2054 +/- 5 years.  The probability of a new record low occurring in the near future are high.  But every new record, is followed by renewed growth.  The odds of back to back records are low.
Please don't try to twist my words as if we agree on this. I believe an "ice-free" arctic minimum will first occur before 2030.

Sorry, but that was not evident from your post.  I still content that fewer scientists support an ice-free state before 2030, and will attach documentation:

https://www.amap.no/documents/doc/Snow-Water-Ice-and-Permafrost.-Summary-for-Policy-makers/1532 (https://www.amap.no/documents/doc/Snow-Water-Ice-and-Permafrost.-Summary-for-Policy-makers/1532)

http://www.pnas.org/content/early/2013/07/10/1219716110 (http://www.pnas.org/content/early/2013/07/10/1219716110)

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016GL070067 (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016GL070067)

Any predictions of when an ice-free Arctic will occur is largely guesswork.  The chaotic nature of the system precludes any such determination.  Could it occur before 2030?  Sure.  Might it takes decades long?  yes.  As Yogi Berra once said, "it's tough making predictions, especially about the future."
Title: Re: Ice-free Arctic
Post by: Archimid on March 20, 2018, 03:41:16 PM
Quote
Sorry, but that was not evident from your post.  I still content that fewer scientists support an ice-free state before 2030, and will attach documentation:

Your contention went from 50-100 years to 2054 +-5 to the late 30's.  Welcome to reality. Please re-assess your risk accordingly. 

BTW

The notion that there is some sort of recovery going on is false.  The first attachment shows the annual Volume Gains and Losses from 1980  to 2017. In 2007 there was a change in behavior. Both Losses and Gains increased significant. See the second attachment.

After 2007 both Gains and Losses increased but the losses increased more than the Gains. For years I have been hearing the speculation that when the volume is very low there will be extra gains that will compensate for the losses. That is not what is happening. What is happening instead is that winter temperatures are going up.

 The third attachment is Gains vs Losses but zoomed in after 2007 to examine the behavior closely.

Of the two worst years for Volume Loss, 2010 and 2012 only the later is followed by record Gain. After 2012, the Volume Loss for every year remained above average but the Gains didn't respond with record increases. Instead it responded with a freezing season much hotter than average at N80. The periphery is also showing signs of decrease freezing momentum. This highly discredits the case that volume gains will improve enough to over take volume losses.


EDIT: SOrry for the hard to read table. It didn't look like that in the preview.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 20, 2018, 05:59:06 PM
I am not saying the late 2030s.  That was another poster.  I am sticking with the 2050s timeframe.
Title: Re: Ice-free Arctic
Post by: Archimid on March 20, 2018, 08:26:29 PM
Since 2 of your 3 links point towards late 30's I thought you changed your mind.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 20, 2018, 08:58:29 PM
No.  I was simply showing the range of opinions, and to show Oren that a multitude of scientists do not agree with his outcome.  There are more references, but I felt that those were sufficient, especially since they pointed to a more dire situation.
Title: Re: Ice-free Arctic
Post by: Archimid on March 21, 2018, 03:00:03 AM
No.  I was simply showing the range of opinions, and to show Oren that a multitude of scientists do not agree with his outcome.  There are more references, but I felt that those were sufficient, especially since they pointed to a more dire situation.

I think this is a more accurate assessment,

When Will the Summer Arctic Be Nearly Sea Ice-Free? 

https://www.researchgate.net/publication/267541077_When_Will_the_Summer_Arctic_Be_Nearly_Sea_Ice-Free

Quote
Observations and citations in this article support the conclusion that current rapid Arctic change, especially loss of multiyear sea ice, is likely out of sample for most CMIP5 models. Thus, time horizons for summer sea ice loss of these three approaches turns out to be roughly 2020, 2030, and 2040 respectively for trendsetters, stochasters, and modelers. Predictions depend on the weight given to data, understanding of Arctic change processes, and the use of model projections.It is reasonable to conclude that Arctic sea ice loss is very likely to occur in the first rather than the second half of the 21st century, with a possibility of loss within a decade or two.

Title: Re: Ice-free Arctic
Post by: Daniel B. on March 21, 2018, 01:43:09 PM
The abstract from this previously cited publication describes the difficulty of ice-free Arctic predictions.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016GL070067 (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016GL070067)

"Climate model simulations give a large range of over 100 years for predictions of when the Arctic could first become ice free in the summer, and many studies have attempted to narrow this uncertainty range. However, given the chaotic nature of the climate system, what amount of spread in the prediction of an ice‐free summer Arctic is inevitable? Based on results from large ensemble simulations with the Community Earth System Model, we show that internal variability alone leads to a prediction uncertainty of about two decades, while scenario uncertainty between the strong (Representative Concentration Pathway (RCP) 8.5) and medium (RCP4.5) forcing scenarios adds at least another 5 years. Common metrics of the past and present mean sea ice state (such as ice extent, volume, and thickness) as well as global mean temperatures do not allow a reduction of the prediction uncertainty from internal variability."
Title: Re: Ice-free Arctic
Post by: Archimid on March 21, 2018, 04:35:00 PM
So because the date of the first ice free Arctic is uncertain, we can just ignore it? No reason to be concerned? That could literally be the worst risk assessment in the history of the world.

In fact, given the vital role of the Arctic in NH weather, the rapid pace of collapse and the serial underestimation of current ice trends by models, the uncertainties are reason for alarm. We can't let the Arctic reach an ice free state.

Title: Re: Ice-free Arctic
Post by: Daniel B. on March 21, 2018, 05:02:11 PM
Why would you not be concerned?  Worst?  It is not like this has never happened before.  It will be an adjustment, but not a catastrophe.

I am equally concerned about the overestimation, and feel that accuracy is important. 
Title: Re: Ice-free Arctic
Post by: Archimid on March 21, 2018, 05:16:52 PM
Quote
Why would you not be concerned?


That's what you advocate at every chance possible in this forum.  There is no reason for concern. Or maybe you now accept there are significant risks associated with the collapse of the Arctic.

Quote
It is not like this has never happened before

For the times frames relevant to humanity, it has never happened before.
Title: Re: Ice-free Arctic
Post by: Archimid on March 21, 2018, 05:54:34 PM
You remind me of Judith Curry. Sad story really, as she is an actual scientist with actual climate knowledge.  Dr. Curry understand every climate change argument and makes note of them in her website, yet once a wee bit of danger rears it's face through the science she devolves into uncertainty arguments for ignoring climate change. Quite sad to see premium minds break down in the face of the dangers presented by climate change.  Like a soldier having a panic attack in a foxhole.

It wouldn't be so bad if they at least kept their panicky rants to themselves instead of interrupting those who dare to face the dangers.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 21, 2018, 06:28:11 PM
I actually take that as a compliment, as she is one of the great minds in physics, and to think that you would actually compare me to someone as accomplished as her is really quite an honor.  Thank you.
Title: Re: Ice-free Arctic
Post by: Archimid on March 21, 2018, 06:54:19 PM
Yeah she is obviously brilliant. That's why is so sad that her emotions got the better of her in the climate change argument.

You seem smart too, unless you are a team of trolls with rehearsed talking points and counterarguments. But in case you are human, you do seem smart, that's why I keep talking to you. I keep having the fools hope that a smart guy like you can disprove what I have shown you. A smart guy like you could potentially have a good explanation as to why the trends will reverse. Or maybe you have a good explanations about why what we are seeing happening in the whole world won't get worse.

But no. So far you are as disappointing as Curry, very knowledgeable about everything, but when it is time to reach the logical conclusion that climate change will be really bad, your emotions get the best of you and you go into denial. Sad.
Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 21, 2018, 11:15:03 PM
First let me be very clear. Your post and my post are talking about two very different things.

you talked about:

When will the Arctic be sea ice free in the summer for the first time?

I talked about:

What happens after the first ice free Arctic, if anything?


There are some short-term negative feedbacks that occur after the ice melts out.  This article describes them: http://pubman.mpdl.mpg.de/pubman/item/escidoc:2461121/component/escidoc:2461125/PAGESmagazine_2017_14-19_Notz.pdf (http://pubman.mpdl.mpg.de/pubman/item/escidoc:2461121/component/escidoc:2461125/PAGESmagazine_2017_14-19_Notz.pdf)

Here's an excerpt:

Quote
Annual variability: The importance of negative
feedbacks
In addition to seasonal forecasts on time scales of a few
months, also forecasts on time scales of a few years
have made some headlines over the past decade. These
headlines were usually related to claims that the Arctic
would lose its remaining summer sea ice within just a few
years. The underlying reasoning of such claims was often
related to a discussion of a possible ’tipping point’ that is
related to the ice-albedo feedback. Given the substantial
loss of Arctic sea ice in the past few years, the ocean
could potentially absorb enough heat to rapidly melt the
remainder of the sea ice cover.
However, our current understanding of the Arctic climate
system strongly suggests that this reasoning is unrealistic.
A first indication for this finding derived from model
experiments in which all Arctic sea ice was synthetically
removed from the Arctic Ocean at the onset of summer,
thus maximising the possible ice-albedo feedback
(Tietsche et al., 2011). Despite such maximised feedback,
the ice cover recovered in these experiments within
just a few years. This is because on annual time scales,
negative feedbacks dominate the evolution of the Arctic
sea ice cover. Three negative feedbacks are particularly
important: First, the open ocean very effectively releases
its heat to the atmosphere during winter, causing a rapid
loss of much of the heat that was accumulated in the icefree
water during summer. Second, the thin ice that forms
during winter can grow much more rapidly than ice that
survived the summer, because heat can more effectively
be transported from the ocean to the atmosphere when
the ice cover is thin (Bitz and Roe, 2004). Third, as ice
forms later in the season, it will carry a thinner insolating
snow cover as any snow fall occurring before ice
formation simply falls into the open ocean (Notz, 2009).
Title: Re: Ice-free Arctic
Post by: Archimid on March 22, 2018, 01:40:46 AM
Quote
First, the open ocean very effectively releases
its heat to the atmosphere during winter, causing a rapid
loss of much of the heat that was accumulated in the icefree
water during summer.

That causes atmospheric warming, which inhibits growth. That is what has been observed over the last three years of record and near record lows. No speed up in ice formation detected. To the contrary.

Quote
Second, the thin ice that forms
during winter can grow much more rapidly than ice that
survived the summer, because heat can more effectively
be transported from the ocean to the atmosphere when
the ice cover is thin

Again, so far the result of the thin cover is a warmer atmosphere that inhibits ice growth.

Quote
Third, as ice
forms later in the season, it will carry a thinner insolating
snow cover as any snow fall occurring before ice
formation simply falls into the open ocean

The story so far is that snow is increasing.


The reasons given for ice recovery are not holding up in reality.

But it gets worst. The model used in your link predicts an ice free Arctic by 2070. Such a late ice free arctic has been discarded by pretty much everyone. That means the assumptions used by the model are significantly underestimating the warming. That heavily invalidates the model.

My guess is that these models are holding the historic winter air temperatures over the Arctic as the likely temperatures when the ice is gone. The observations don't support that at all. What the observations support is significant warming of the Arctic winter when the ice is record low. Warmer air temperatures mean less ice formation.  After the ice is gone, it won't come back until the CO2 is gone or milankovitch cycles force it.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 22, 2018, 02:12:38 PM
Yeah she is obviously brilliant. That's why is so sad that her emotions got the better of her in the climate change argument.

You seem smart too, unless you are a team of trolls with rehearsed talking points and counterarguments. But in case you are human, you do seem smart, that's why I keep talking to you. I keep having the fools hope that a smart guy like you can disprove what I have shown you. A smart guy like you could potentially have a good explanation as to why the trends will reverse. Or maybe you have a good explanations about why what we are seeing happening in the whole world won't get worse.

But no. So far you are as disappointing as Curry, very knowledgeable about everything, but when it is time to reach the logical conclusion that climate change will be really bad, your emotions get the best of you and you go into denial. Sad.

Thank you for your openness and honesty (and the compliment).  I do want to reiterate that I am not saying that the trends will reverse, just that they will slow.  Very little in nature can sustain exponential change for long, and the Arctic sea ice is no exception.  Many that are claiming the Arctic will be ice-free in a shorter time are just fitting the data to a second-order curve and arriving at a numerical value.  That is largely what the Jahn, et. al. paper is saying; namely that estimates of an ice-free Arctic depend largely on the weight given by modelers to different data.  What is missing in all these predictions is the physics of the system.  Check out the NASA images take at the minimum for each year since 1979.  Look closely at where the bulk of the ice has been lost over the decades.

https://climate.nasa.gov/vital-signs/arctic-sea-ice/ (https://climate.nasa.gov/vital-signs/arctic-sea-ice/)

The majority of the ice loss occurs from the Alaskan side, the Beaufort Sea, and the Russian side, from the Barents to the East Siberian Sea.  Much less is lost from the ice abutting the Canadian archipelago and Greenland.  The opens up water flow from the Atlantic to the Pacific via the Russian coast.  See the following:

http://www.clivar.org/news/northern-oceans-region-panel-has-been-established-clivar-and-clic (http://www.clivar.org/news/northern-oceans-region-panel-has-been-established-clivar-and-clic)

In recent years, the measured ice minimum is affected largely by these currents, and the strength of the gyres in the Arctic (much research still needs to be done on how these currents may change in the future and affect the sea ice).  If greater amounts of warm water is circulated through the Arctic, the ice shrinks substantially, e.g. 2007 and 2012.  In other years, larger amounts of ice remains.  Hence, recent minima have fluctuated significantly as large swatches of floating sea teeter on the edge of melting and freezing.  The ice adjacent to the Canadian islands and Greenland are protected from this influx of warmer water, and remain frozen year round.  Many of these islands are glacier-covered, which contribute to the surrounding ice pack.  The average temperature on these islands exceeds freezing for barely two months of the year, and averages -20F (-30C) in the depths of winter.  The helps facilitate ice growth.  Here is a nice video of the ice thickness over time:

https://www.google.com/search?q=arctic+sea+ice+volume+image&rlz=1C1GGRV_enUS751US751&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwiZx9q8gIDaAhWPnOAKHZhGAAsQsAQIKw&biw=1600&bih=794#imgrc=epY_MfBFMZuFeM: (https://www.google.com/search?q=arctic+sea+ice+volume+image&rlz=1C1GGRV_enUS751US751&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwiZx9q8gIDaAhWPnOAKHZhGAAsQsAQIKw&biw=1600&bih=794#imgrc=epY_MfBFMZuFeM:)

The largest decrease in sea ice minimum has already occurred, and further decreases will be much less.  This is not necessarily true of the maximum extent.  Hence, even linear extrapolations of the sea ice minimum may be too severe as the ice shrinks.  Thanks for listening.
Title: Re: Ice-free Arctic
Post by: oren on March 22, 2018, 03:14:33 PM
...
In recent years, the measured ice minimum is affected largely by these currents, and the strength of the gyres in the Arctic (much research still needs to be done on how these currents may change in the future and affect the sea ice).  If greater amounts of warm water is circulated through the Arctic, the ice shrinks substantially, e.g. 2007 and 2012.  In other years, larger amounts of ice remains.
...
In 2012 the extraordinary melt happened due to mostly clear skies during spring, with extensive melt ponds preconditioning the ice. A final punch was the August cyclone. Not sure where you got the warm currents explanation.
Title: Re: Ice-free Arctic
Post by: Archimid on March 22, 2018, 03:46:31 PM
Quote
I do want to reiterate that I am not saying that the trends will reverse, just that they will slow.

Why would the trends slow? It makes no physical sense.  The globe is warming and the Arctic is warming the fastest. That should increase the losses and reduce the gains. There is less ice than ever to absorb the summer warming. The periphery is opening earlier letting in more sun than ever. After the 2007 phase changes the ratio of losses to gains increased, meaning it got worst. If what you say is true it should have gotten better.

Quote
Very little in nature can sustain exponential change for long, and the Arctic sea ice is no exception

In real life unchecked asymptotic behavior leads to collapse of the system into a new state. In the specific case of the Arctic what is driving the asymptotic behavior is global warming and all science indicates the global warming will continue AND accelerate. There is no reason to think the asymptotic behavior will simply decrease.

Quote
Many that are claiming the Arctic will be ice-free in a shorter time are just fitting the data to a second-order curve and arriving at a numerical value.

Wrong.  A linear fit puts the first ice free Arctic in 20 years. No second order needed. The same fit 20 years ago had the ice lasting until late 21'st century. The trend of the linear trends is decidely down.

 
Quote
What is missing in all these predictions is the physics of the system. 

The physics couldn't get more basic. More warmth = less ice. You are claiming the complete opposite without any physical basis other than your expectation that when there is less ice, the Arctic swill somehow grow more ice or lose less ice.  Your claims are the complete opposite of the observations so far. You still do not give a reason why the trends should slowdown.

Quote
The majority of the ice loss occurs from the Alaskan side, the Beaufort Sea, and the Russian side, from the Barents to the East Siberian Sea.  Much less is lost from the ice abutting the Canadian archipelago and Greenland.

Extent is not a measure of how much ice there is, how much ice is gained or how much ice is lost. Extent only measures the surface area the ice covers. Volume is the correct measure of ice loss.

Using volume, most ice was lost in the thickest part of the Arctic.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fnsidc.org%2Fsites%2Fnsidc.org%2Ffiles%2Fimages%2Fcryosphere%2Fsotc%2Fseaiceage-mar-1990-2016.png&hash=45b922c16eacc0b73c674c25e909920d)

Quote
Hence, recent minima have fluctuated significantly as large swatches of floating sea teeter on the edge of melting and freezing.

Yeah, but the result of the fluctuation is a sharp increase in ice loss, as shown in the tables I posted above.

Quote
The largest decrease in sea ice minimum has already occurred, and further decreases will be much less.


Again that's an extraordinary claim, wishful thinking. There is absolutely no reason to believe that we won't have losses like in 2012 and 2016 again. The complete opposite is true. The likelihood of large melt events increases with the global temperatures, the decay of the arctic periphery, and the waviness of the jet streams.

Once again your claim remains that conditions won't get worse in the Arctic before that is scary. That's it. Just like Curry emotions got the best of you.
Title: Re: Ice-free Arctic
Post by: Gray-Wolf on March 22, 2018, 04:33:31 PM
https://www.nature.com/articles/s41598-018-22854-0.pdf

appears low solar increases winter temps over the basin....... I though they were becoming warm enough and now we have a winter warm up to face as we move into low solar???

I'd have thought the trend of our record breaking years all being over low solar might point to issues over summer come low solar?

We've known since the noughties that over winter low solar leads to a propensity of high northern blocking over the N Atlantic. Does this propensity to HP dominance then slip into the high arctic over summer as the ITCZ heads toward the tropic?

If this is true then we can expect a move toward increased melt ponding on the Atlantic side as high pressure leaves clear blue skies for the start of melt season...... the rest is ( recent Arctic) History!
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 22, 2018, 05:01:16 PM
We may be talking about two different aspects.  I am talking about the minimum, and it appears that you are referencing the maximum. 

(https://protonsforbreakfast.files.wordpress.com/2016/03/extent-graph-2016.jpg)

The 2016 Arctic minimum extent (according to NSIDC) was 4.14 million sq. km.  Using a linear fit, the sea ice extent will fall below 1 million in 38 years. Based on the current trend, it will be centuries before the maximum would hit that level.

The largest decline occurred in 2017.  No other year was close, not even the record low in 2012.

Obviously we disagree about what is the best measure for the Arctic sea ice.  However, if you are going to use volume for your metric, you cannot relate the surface albedo to volume.  They are two different measures.  The thickness of the ice is largely irrelevant to any surface affects, whether it is albedo or weather changes due to open water.

If you have been following the other threads, which I presume you are, you should have read about the increased cloud cover in the Arctic.  This has a two-fold effect; increasing winter temperatures by reducing heat loss, and lower summer temperatures by blocking incoming solar radiation.  This could explain why the 2017 minimum was only the 8th lowest, and higher than all but three of the past eleven years, while simultaneously increasing the rate of the winter maximum.  In 1996, the minimum sea ice extent was 7.191 million sq. km (NSIDC).  In 2012, it was 3.387.  Physically, it is impossible to lose a similar amount.

Once again, no one is saying that more warmth equates to more ice.  In rather simplistic terms, ice will increase if the average temperature is below freezing and decrease if it is above.  The regions that I mentioned previously will remain below freezing for quite some time, and stem the losses from the increasing area that will average above freezing temperatures with the coming temperature rise.  Basic physics.

The August cyclone in 2012 entered the Arctic from the Siberian side, in the warmer waters.  As it moved towards the center of the Arctic, it carried with it some of that warmer water, and the combination of warmer water and intense wave action disintegrated much of the fragile ice.  This was an unusual event for summer.  It has not been replicated since, and consequently, summer sea ice extent has been higher in recent years.  Any trend line that ended in 2012 gave a false impression of higher ice loss.
Title: Re: Ice-free Arctic
Post by: oren on March 22, 2018, 05:38:12 PM
The 2016 Arctic minimum extent (according to NSIDC) was 4.14 million sq. km.  Using a linear fit, the sea ice extent will fall below 1 million in 38 years.
Nice Chart you've got there. With a thick enough marker you can do anything. But did you ever wonder why, when looking at the minimum (bluish) linear fit, the first decade or so has most of it actual dots below the line, then the middle decades have their dots above the line, and the last decade comes out mostly below the line? That's because the fit doesn't really fit. Arctic sea ice was declining slowly until ~1995, and then started declining more rapidly. Try using a two-line fit and you'll get interesting results.
Or if you want, try to calculate what your method would have supplied back in 1990, 2000, 2010, and see if expected the date of falling below 1m km2 keeps moving closer. (Though I have a feeling your chart is taken from somewhere, potentially somewhere with an agenda, and is not self-calculated).
Title: Re: Ice-free Arctic
Post by: gerontocrat on March 22, 2018, 05:55:13 PM

The 2016 Arctic minimum extent (according to NSIDC) was 4.14 million sq. km.  Using a linear fit, the sea ice extent will fall below 1 million in 38 years.

Last year there was a big argument about volume vs extent. This is what my arithmetic said. Despite ups and downs, the loss of volume in September has been about 1.8 percent per annum of the 1979 volume. The linear fit has worked amazingly well.  The same can be said of September extent, reducing at the lower rate of 1.25% per annum, the linear fit being the best fit.

The result is that in September 2017 73% of the volume was gone, but only 50% of the extent. This is not feasible in the long-term. As no-one has come up with verifiable data to show that the arithmetic change in volume and extent has changed, then looking forward one can use the same parameters until proven otherwise.

By 2032 the result is absurd. Volume is zero, extent is still 31%. So for me the question is -  when will this relationship break down ?

Arguing from extent vs volume is arguing about two measures of the same thing.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 22, 2018, 05:57:45 PM
The 2016 Arctic minimum extent (according to NSIDC) was 4.14 million sq. km.  Using a linear fit, the sea ice extent will fall below 1 million in 38 years.
Nice Chart you've got there. With a thick enough marker you can do anything. But did you ever wonder why, when looking at the minimum (bluish) linear fit, the first decade or so has most of it actual dots below the line, then the middle decades have their dots above the line, and the last decade comes out mostly below the line? That's because the fit doesn't really fit. Arctic sea ice was declining slowly until ~1995, and then started declining more rapidly. Try using a two-line fit and you'll get interesting results.
Or if you want, try to calculate what your method would have supplied back in 1990, 2000, 2010, and see if expected the date of falling below 1m km2 keeps moving closer. (Though I have a feeling your chart is taken from somewhere, potentially somewhere with an agenda, and is not self-calculated).

Yes, the fit does not match the data very well.  I was using it in response to the previous post to show when the Arctic would reach an ice-free state using a linear fit.  I usually use a three-fit line, 1979-1996, 1996-2007, and 2007-present, for the reasons you mentioned.  The decline was much less than the average fit over the first two decades, much higher as the sea ice declined  more rapidly during that middle decade, and much less during the most recent decade.  Indeed, 93% of the decrease occurred during that middle timeframe.
Title: Re: Ice-free Arctic
Post by: Sleepy on March 22, 2018, 10:20:34 PM
What does it match? Interesting to see who commented there last year and why:
*ttps://protonsforbreakfast.wordpress.com/2017/03/25/arctic-sea-ice-update-everything-is-proceeding-exactly-as-we-had-foreseen/#comment-30616
Victor Venema:
Quote
Sea ice extent and volume cannot be zero at different times. For extrapolation you need to understand what is happening. Thus I would prefer a climate model with a good sea ice module interpreted by an expert over a statistical extrapolation.

The satellite measurements of sea ice are photography in the sense that you get a photo, a map out of it. However, they are not visible images, but microwave radiometry. It can be pretty dark at the poles and it is also hard to distinguish clouds from snow and ice. Microwaves can look through the clouds and water and ice have a very different microwave emissivity.

*ttps://protonsforbreakfast.wordpress.com/2017/03/25/arctic-sea-ice-update-everything-is-proceeding-exactly-as-we-had-foreseen/#comment-30639
Neven:
Quote
When all you do, is look at sea ice extent data and graphs, and not at how this freezing season has evolved (air and sea surface temperatures, freezing degree days, satellite radar images, multi-year ice distribution, Fram Strait export, PIOMAS, etc.), leading to a third lowest maximum on record in a row, it is no wonder that you do not understand what a veteran expert means when he says:

“I have been looking at Arctic weather patterns for 35 years and have never seen anything close to what we’ve experienced these past two winters”

The arguing about volume vs extent metrics has been a persistent feature on this forum as far as I can remember. It doesn't really matter, a summer like 2007 might be all it takes for a new record this September. Another metric is to see how many comments the melting season thread collects in May/June. ;)
Title: Re: Ice-free Arctic
Post by: crandles on March 23, 2018, 12:41:18 AM
Here is a better fit.  ;)

(https://farm6.staticflickr.com/5660/21486235516_5095ee4562_z.jpg) (https://flic.kr/p/yJEzfu)Piomasmaxminmeltfreeze (https://flic.kr/p/yJEzfu) by crandles57 (https://www.flickr.com/photos/37346653@N05/), on Flickr

Perhaps looks a bit too horizontal at the end. However I think the acceleration and deceleration is physically explainable in terms of getting rid of old thick ice.
Title: Re: Ice-free Arctic
Post by: Archimid on March 23, 2018, 02:06:02 AM

Obviously we disagree about what is the best measure for the Arctic sea ice.  However, if you are going to use volume for your metric, you cannot relate the surface albedo to volume.  They are two different measures.  The thickness of the ice is largely irrelevant to any surface affects, whether it is albedo or weather changes due to open water.

If we were talking about albedo, extent would be a good metric, but we are not talking about albedo. We are talking about when the Arctic will be ice free for the first time. For that the best measure is volume for two good reasons. One, extent has no information about ice content, volume does. The second one is that volume hits 0 first. 0 volume = 0 extent.  Gerontocrat already illustrated that.

Quote
If you have been following the other threads, which I presume you are, you should have read about the increased cloud cover in the Arctic.  This has a two-fold effect; increasing winter temperatures by reducing heat loss, and lower summer temperatures by blocking incoming solar radiation.

This is the first actual argument you give for a slow down. Clouds. Clouds block sun, but keeps warmth in who wins? Remains to be seen, but it seems to me that it should help slow down the melt during summer but also slow down refreezing in the winter

Quote
This could explain why the 2017 minimum was only the 8th lowest, and higher than all but three of the past eleven years, while simultaneously increasing the rate of the winter maximum.

That's extent. 2017 was the 3rd lowest min volume on record, the lowest max volume on record and the lowest annual average volume on record.


Quote
In 1996, the minimum sea ice extent was 7.191 million sq. km (NSIDC).  In 2012, it was 3.387.  Physically, it is impossible to lose a similar amount.

It is not physically impossible at all. In fact, it is very likely that some time soon that record is smashed.

Quote
Once again, no one is saying that more warmth equates to more ice.  In rather simplistic terms, ice will increase if the average temperature is below freezing and decrease if it is above. 

Wrong. How much ice is created depends on how many freezing degree days the arctic gets. At -40 tons of ice will form and at -20 much less ice will form. The tendency over the last three year is of much warmer winters that lead to record low ice formation.

Quote
The regions that I mentioned previously will remain below freezing for quite some time, and stem the losses from the increasing area that will average above freezing temperatures with the coming temperature rise.  Basic physics.


It's not just a matter of remaining below freezing. Sea ice won't even form until air temperatures are at about -10C. The colder it gets the more ice forms.  As I said before, the Arctic winter is getting much warmer. Basic physics

Quote
The August cyclone in 2012 entered the Arctic from the Siberian side, in the warmer waters.  As it moved towards the center of the Arctic, it carried with it some of that warmer water, and the combination of warmer water and intense wave action disintegrated much of the fragile ice.  This was an unusual event for summer.  It has not been replicated since, and consequently, summer sea ice extent has been higher in recent years.  Any trend line that ended in 2012 gave a false impression of higher ice loss.

Sure but what makes you think that it won't happen again?  I would  think that since such event is new in the record , and it only happened when the Arctic was at record low levels, it seems reasonable to assume that while the Arctic remains at low levels, chances of a GAC happening again are high.


Perhaps looks a bit too horizontal at the end. However I think the acceleration and deceleration is physically explainable in terms of getting rid of old thick ice.

That is indeed a better fit. However, if you include 2016 and 2017 the two last data points fall below the line of the minimum, pulling the line further down. If you include 2016 and 2017 the maximum pulls decidedly down. I doubt you can fit the same curve to the Max.

That's why I use the maximum to make my argument not the minimum. Even if the minimum stayed at the levels of the past 8 years, the max "predicts" the ice to be gone anywhere from the late 20's to the late 30's.
Title: Re: Ice-free Arctic
Post by: oren on March 23, 2018, 02:59:27 AM
The 2016 Arctic minimum extent (according to NSIDC) was 4.14 million sq. km.  Using a linear fit, the sea ice extent will fall below 1 million in 38 years.
Nice Chart you've got there. With a thick enough marker you can do anything. But did you ever wonder why, when looking at the minimum (bluish) linear fit, the first decade or so has most of it actual dots below the line, then the middle decades have their dots above the line, and the last decade comes out mostly below the line? That's because the fit doesn't really fit. Arctic sea ice was declining slowly until ~1995, and then started declining more rapidly. Try using a two-line fit and you'll get interesting results.
Or if you want, try to calculate what your method would have supplied back in 1990, 2000, 2010, and see if expected the date of falling below 1m km2 keeps moving closer. (Though I have a feeling your chart is taken from somewhere, potentially somewhere with an agenda, and is not self-calculated).

Yes, the fit does not match the data very well.  I was using it in response to the previous post to show when the Arctic would reach an ice-free state using a linear fit.  I usually use a three-fit line, 1979-1996, 1996-2007, and 2007-present, for the reasons you mentioned.  The decline was much less than the average fit over the first two decades, much higher as the sea ice declined  more rapidly during that middle decade, and much less during the most recent decade.  Indeed, 93% of the decrease occurred during that middle timeframe.
So, at least we agree where we disagree, which is good. I believe that third line is non-existent, and that the use of 2007 as a pivot is blatant cherry-picking, creating a fake hiatus in sea ice minima, same as cherry-picking the 1998 El-Nino for a pivot year created a fake hiatus in the rise of global surface temps. As often happens with such fake lines, when it breaks it usually does so in quite a dramatic fashion.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 23, 2018, 03:21:36 AM
The 2016 Arctic minimum extent (according to NSIDC) was 4.14 million sq. km.  Using a linear fit, the sea ice extent will fall below 1 million in 38 years.
Nice Chart you've got there. With a thick enough marker you can do anything. But did you ever wonder why, when looking at the minimum (bluish) linear fit, the first decade or so has most of it actual dots below the line, then the middle decades have their dots above the line, and the last decade comes out mostly below the line? That's because the fit doesn't really fit. Arctic sea ice was declining slowly until ~1995, and then started declining more rapidly. Try using a two-line fit and you'll get interesting results.
Or if you want, try to calculate what your method would have supplied back in 1990, 2000, 2010, and see if expected the date of falling below 1m km2 keeps moving closer. (Though I have a feeling your chart is taken from somewhere, potentially somewhere with an agenda, and is not self-calculated).

Yes, the fit does not match the data very well.  I was using it in response to the previous post to show when the Arctic would reach an ice-free state using a linear fit.  I usually use a three-fit line, 1979-1996, 1996-2007, and 2007-present, for the reasons you mentioned.  The decline was much less than the average fit over the first two decades, much higher as the sea ice declined  more rapidly during that middle decade, and much less during the most recent decade.  Indeed, 93% of the decrease occurred during that middle timeframe.
So, at least we agree where we disagree, which is good. I believe that third line is non-existent, and that the use of 2007 as a pivot is blatant cherry-picking, creating a fake hiatus in sea ice minima, same as cherry-picking the 1998 El-Nino for a pivot year created a fake hiatus in the rise of global surface temps. As often happens with such fake lines, when it breaks it usually does so in quite a dramatic fashion.

That may be true.  Perhaps a third-order fit, similar to the fit in chandler graph would be better.  Using 2007 as a pivot is no more a cherrypick that using 1996 as a pivot.  If the trend changes it changes.  Using a third order fit will smooth it out some, but if it real, it will show.
Title: Re: Ice-free Arctic
Post by: Sleepy on March 23, 2018, 08:01:39 AM
Thomas posted this in another thread.
https://www.ecowatch.com/katharine-hayhoe-climate-change-2550366098.html (https://www.ecowatch.com/katharine-hayhoe-climate-change-2550366098.html)
Quote
Hayhoe vehemently advises against engaging with the "smokescreens" skeptics tend to offer as the reasons they couldn't possibly agree with or act on the issue of climate change. "There'll be no progress that way," she insists. "It's a lot easier for people to say, 'I have a problem with the science' than it is to talk about what the real problem is."
Title: Re: Ice-free Arctic
Post by: Capt Kiwi on March 23, 2018, 10:06:00 AM
Why would you not be concerned?  Worst?  It is not like this has never happened before.  It will be an adjustment, but not a catastrophe.

It has happened before, but not with around 7.5 billion people pointing nuclear weapons at each other. Civilisation is now fragile and vulnerable. The time of human hunter gathering populations having options such as migration or food alternatives is long behind us.
It would be a catastrophe.
Title: Re: Ice-free Arctic
Post by: crandles on March 23, 2018, 01:51:01 PM

Perhaps looks a bit too horizontal at the end. However I think the acceleration and deceleration is physically explainable in terms of getting rid of old thick ice.

That is indeed a better fit. However, if you include 2016 and 2017 the two last data points fall below the line of the minimum, pulling the line further down. If you include 2016 and 2017 the maximum pulls decidedly down. I doubt you can fit the same curve to the Max.

That's why I use the maximum to make my argument not the minimum. Even if the minimum stayed at the levels of the past 8 years, the max "predicts" the ice to be gone anywhere from the late 20's to the late 30's.

It is a better fit but uses more parameters so you would expect it to be better. Whether it is sufficiently better is a tougher question.

>However, if you include 2016 and 2017 the two last data points fall below the line of the minimum, pulling the line further down.

Yes of course but so what? If you insist on exponential fit and look back at previous fits to earlier years, that is much worse.

>I doubt you can fit the same curve to the Max.

Of course I can (see below). It may not look good for the last year but this curve can morph into an exponential curve(over relevant date range), however it finds it better to level out at a surprisingly high level.

Note I don't believe the horizontal project, I believe it should still be going down.

>That's why I use the maximum

I agree with you on the importance of the maximum.

However the trend extrapolation does not go where you think it goes.
Title: Re: Ice-free Arctic
Post by: Archimid on March 23, 2018, 02:21:46 PM
Sorry Crandles but that doesn't fit the curve.  Sure you can put it there and create an illusion that it does but no data point matches the last inflection. The last inflection is pure fantasy.

Quote
Yes of course but so what? If you insist on exponential fit and look back at previous fits to earlier years, that is much worse.

No exponential fit needed. A linear fit to the max has the ice gone anywhere from the late 20's to the late 30's. Of course that excludes GAC's and min volume/max loss events. That's only the most basic averages devoid of any other information.

Quote
However the trend extrapolation does not go where you think it goes.

The trend goes where it goes regardless of where I think it goes. The trend of the trends also go where it goes without the need for speculation.

As far as the Minimum volume goes, the apparent hiatus is very likely similar to the hiatus in global temperatures. It will end soon and it will be spectacular. That's what's expected in a warming world.
Title: Re: Ice-free Arctic
Post by: crandles on March 23, 2018, 02:32:26 PM
That fit wasn't hand tweaked to get it, it was produced by spreadsheet solver. It isn't pure fantasy, it is standard least squares fit.

I am more sure of the physical basis for levelling out of the max than of the minimum.

You criticised linear fit for ignoring persistence of anomalies but now when someone shows you where the curve is heading, you are back to preferring a straight line despite the persistence of anomalies. Does this have a faint smell of you having decided on your conclusion and now you are prepared to bend the arguments any way you need to in order to stick to your original conclusion?

Title: Re: Ice-free Arctic
Post by: El Cid on March 23, 2018, 02:36:45 PM
As for your charts:
- Sept Volume is a good fit, as it really has not been going anywhere for a decade
- It is also true, that Apr volume is relentlessly falling and your fit does not fit.

 So, what gives? I have no clue...
Title: Re: Ice-free Arctic
Post by: Archimid on March 23, 2018, 02:46:55 PM
Quote
That fit wasn't hand tweaked to get it, it was produced by spreadsheet solver. It isn't pure fantasy, it is standard least squares fit.

If you tell your solver of choice to fit a nth order line it will do so and it would be fantasy if the lines do not meet the data. In your case the last inflection does not exists in the data, thus that line is pure fantasy.

Quote
I am more sure of the physical basis for levelling out of the max than of the minimum.

Care to share? I would love to know.

Quote
You criticised linear fit for ignoring persistence of anomalies but now when someone shows you where the curve is heading, you are back to preferring a straight line despite the persistence of anomalies


Wait what? I've only used linear fits so for all my arguments. I prefer the straight line everytime because there is no human choice in it. Only the simplest math possible. To me that is very powerful if you understand the limitation.

Your curve simply doesn't fit. Thanks for proving my point. No point after the inflection chosen by your algorithm fits the line.

Quote
Does this have a faint smell of you having decided on your conclusion and now you are prepared to bend the arguments any way you need to in order to stick to your original conclusion?

Because believing your own eyes would force you to arrive to some very difficult conclusions. Thus you imagine I used exponential curves and you imagine that line fits the max, even when no data point after the inflections falls anywhere near or above the line.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 23, 2018, 02:52:24 PM
Trying to fit data from a chaotic system to a particular curve will never yield an exact match.  There are simple too many variables for that to occur.  Additionally, putting too much emphasis on a single data point, such should not be a reason to discard the entire curve.  Sometimes it is just statistical probability that a particular data point lies further from the norm.  The curve that crandles presented is as good as any (probably better), and should lead to trying to understand why the Arctic is doing what the data states.
Title: Re: Ice-free Arctic
Post by: Gray-Wolf on March 23, 2018, 03:16:01 PM


As far as the Minimum volume goes, the apparent hiatus is very likely similar to the hiatus in global temperatures. It will end soon and it will be spectacular. That's what's expected in a warming world.

I'm desperately hoping that low solar is not the piece that was missing to keep us from constant drops in extent/area/volume?

As I see things we had a run of poor years that saw records for either volume/extent/area smashed and they were over the lower end of the solar cycle. If the 2 perfect melt storms before 07' were 10 years apart then these would also have fallen in the lower end of solar cycles too?

I know that there are far more variables in the mix ( ENSO/PDO/QBO etc ) but if we have seen low solar as a way to get high melt/high transport in place then we have an interesting 3 or 4 years in front of us again?

My concern is that the ice is no longer capable of surviving another 3 record breaking years of the order we saw last low solar.

As ever the losses are not a straight line as the last amount of ice will feel far more melt pressures than other times so as we approach blue ocean I imagine the ice tends to go faster. It might even be there is a volume that we dare not fall below as the ice will then melt out in the volume of open water it exists in?

If this year shows any tendency toward sunnier/clearer spells across wide areas I will really begin to worry about the next few melt seasons!!!
Title: Re: Ice-free Arctic
Post by: Archimid on March 23, 2018, 03:17:18 PM
Quote
Trying to fit data from a chaotic system to a particular curve will never yield an exact match.

Of course.

Quote
There are simple too many variables for that to occur. 

If there weren't unknown variables it wouldn't be a chaotic system. It would be a perfectly understood system and perfectly predictable with enough computing power.

Quote
Additionally, putting too much emphasis on a single data point, such should not be a reason to discard the entire curve.

True.

 Fun fact, we are talking about 2 maybe 3 datapoints in a 39 datapoint set. All of them go distinctively down. I'm not saying they eventually won't go back up. They very well might. But right now, today, that is not a fit. Funny thing how you are all doing the same thing you accuse others of doing.


Quote
  The curve that crandles presented is as good as any (probably better), and should lead to trying to understand why the Arctic is doing what the data states.


The proper use of that line fitted to that data is to illustrate what Crandles think the data will do. That's it. That line is just Crandles opinion of what the data will do in the future stated in graphical form. For that purpose, it is useful so long as you know it is an opinion. It doesn't tell you anything about the data in it's current state because it does not fit.

Title: Re: Ice-free Arctic
Post by: crandles on March 23, 2018, 04:00:31 PM
but no data point matches the last inflection. The last inflection is pure fantasy.

The parameters for Sept obtained by solver are
GompertzP1      10.10425246
GompertzP2      0.1094476679
GompertzP3      2005.912046
GompertzP4      21.78509903

This tells me there is one inflection point in 2005.91, so all the data from 2006 onwards is saying the steep part is levelling off. (So ignore 2006 and that leaves 11 years of data, yet you seem unable to see it.

April gompertz fit has inflection at 2005.09. I would be surprised if there was a perfect match so this seems pretty good agreement between the two.

(Not sure what you are on about when you say no data point matches it.)

Use enough parameters and you can fit the data and have the extrapolation going wherever you want it to. By selecting this curve type for my fit, I am insisting it goes horizontal at some point, but if it resulted in a better fit this could be year 1,000,000 or later. I don't really believe the data extrapolation should go horizontal, it should still be downwards. However it it useful to see where and what level it levels out at and the answer is soon and high. All models are wrong but some are useful.

Title: Re: Ice-free Arctic
Post by: crandles on March 23, 2018, 04:04:54 PM
Care to share? I would love to know.

You have seen it all before on the slow transition thread and on dosbat linked posts. You choose to refuse to see/understand it before so why should I bother repeating it?
Title: Re: Ice-free Arctic
Post by: gerontocrat on March 23, 2018, 04:21:31 PM
If you tell your solver of choice to fit a nth order line it will do so and it would be fantasy if the lines do not meet the data.

My mathematical statistics lecturer (from Uttar Pradesh) at Uni in 1966 told us that one looks for the best fit (i.e. usually highest R2 value). Mind you we did it by using mechanical difference machines - so linear and x2 (if enough time) on small samples was the best we could do. My opinion (humble or not) is that it is good practice to show the R2 value on the graph (dead easy in excel).

One of the problems with least squares is that the higher the order of the polynomial usually the better the fit. A complex equation can follow the ups and down of the data so much better than low order and linear equations. In other words it is simply a matching of data to an equation. Another problem is that R2 gives equal weight to all the observations, when one's hypothesis may wish to give more weight to more recent data.

To then use that to predict into the future is really dodgy, and for best practice more than one equation should be used to demonstrate a range of possibilities.

I have produced some Armageddon scenario stuff. One I liked showed massive increases in arctic sea ice extent using an x6 equation, and a huge drop in extent using an x5 equation (or was it the other way round?).

So most times I don't dare speculate using statistics more than a year or two ahead - and even then with huge caveats.
Title: Re: Ice-free Arctic
Post by: crandles on March 23, 2018, 04:57:54 PM
RMSE for April straight line fit = 1.031
RMSE for April 4 parameter gompertz fit = 0.834

RMSE for Sept straight line fit = 1.397
RMSE for Sept 4 parameter gompertz fit = 1.023

4 parameters versus 2 parameters is unfair comparison.

The improvement is greater for Sept than for April with a ratio of .81 compared to .73. Make of that what you will.

Sorry not sure how to properly calculate an R^2 for a curve. I can share the google sheets spreadsheet if anyone wants it.
Title: Re: Ice-free Arctic
Post by: gerontocrat on March 23, 2018, 05:19:27 PM
Sorry not sure how to properly calculate an R^2 for a curve. I can share the google sheets spreadsheet if anyone wants it.

I don't know what google sheets can do or not do.
But in an MS office spreadsheet graph, do the the following-

click inside the graph,
click on the trend-line,
on the menu bar click the FORMAT option in the DESIGN bit.
In the left hand corner click "format selection",

On the right loads of stuff appears.  That's where you change the characteristics of your trendline.
Go down until you find the options to place the equation and / or the the R2 value on your graph.

After 3 or 4 attempts you will wonder what the problem was (it took me that long)

Have fun
Title: Re: Ice-free Arctic
Post by: Archimid on March 23, 2018, 06:12:06 PM
Care to share? I would love to know.
You have seen it all before on the slow transition thread and on dosbat linked posts. You choose to refuse to see/understand it before so why should I bother repeating it?

Let see if I understand the argument of The Slow Transition (one of the best threads on ASIF, everyone should read it).

The basis for the argument is the phenomena depicted in this graph posted by Chris Reynolds in the slow transition thread.

(https://farm4.staticflickr.com/3824/9586307013_77132e9dd4_o.jpg)

Given the average Arctic winter temperatures, the growth rate of the ice increases exponentially with ice thinness.

So obviously the thinner the ice, the faster the ice will grow. In theory the ice losses should reduce significantly as the ice grow thinner because the ice will grow faster.

We might very well have that phenomenon at play right now. Look at how fast the volume grew last week while N80 temperatures were near the average:
(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=119.0;attach=98528;image)

So, yes that phenomenom is real.

Did I get that right?  If I did my argument is that Arctic winter temperatures are no longer average.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Focean.dmi.dk%2Farctic%2Fplots%2FmeanTarchive%2FmeanT_2018.png&hash=05f12172b4c7018e77e2dabe03f465af)

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=2141.0;attach=98501;image)


Temperatures also tie in with ice growth:


(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=1611.0;attach=88074;image)


Thin ice grows faster but warmer ice grows slower. Who wins? I don't know. But I do know that since the one record high volume gain year in 2013, volume has not recovered in any significant way. The opposite is true. I also know that temperatures are expected to climb.


Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 23, 2018, 09:43:02 PM
Here's a good article on the sensitivity of trend analysis with Arctic sea ice:  http://www.mdpi.com/2072-4292/10/2/230 (http://www.mdpi.com/2072-4292/10/2/230)

Here's an extract from the article:
Quote
Using an inter-calibrated satellite sea ice product, this article examines the sensitivity of decadal trends of Arctic sea ice extent and statistical projections of the first occurrence of an ice-free Arctic summer. The projection based on the linear trend of the last 20 years of data places the first Arctic ice-free summer year at 2036, 12 years earlier compared to that of the trend over the last 30 years. The results from a sensitivity analysis of six commonly used curve-fitting models show that the projected timings of the first Arctic ice-free summer year tend to be earlier for exponential, Gompertz, quadratic, and linear with lag fittings, and later for linear and log fittings. Projections of the first Arctic ice-free summer year by all six statistical models appear to converge to the 2037 ± 6 timeframe, with a spread of 17 years, and the earliest first ice-free Arctic summer year at 2031.

Title: Re: Ice-free Arctic
Post by: crandles on March 23, 2018, 09:44:48 PM
Ice grows faster when it is thinner is certainly part of the slow transition argument, but far from all of it.

We should look to the scientific literature to see if there is anything different about the ~1998-~2012 period.

There is a big change in the quantity of MYI and an explanation in the literature is the failure of the beaufort gyre acting as a flywheel giving time for the MYI to age and thicken. The MYI ceased surviving the trip around the gyre and the consequence was the quantity, average age and thickness of MYI plummeted.

See for example http://dosbat.blogspot.co.uk/2012/05/transition-complete.html

>"I also know that temperatures are expected to climb."

Yes and that is going to reduce the thickness of the FYI over time. Do the temperature rises mean this effect dominates other effects such as rapid decline in MYI quantity, age and thickness? That is a tougher question that requires some quantification. In these circumstances you need to know more than just 'the temperatures are expected to climb'.

Title: Re: Ice-free Arctic
Post by: crandles on March 23, 2018, 09:50:19 PM
Here's a good article on the sensitivity of trend analysis with Arctic sea ice:  http://www.mdpi.com/2072-4292/10/2/230 (http://www.mdpi.com/2072-4292/10/2/230)

Here's an extract from the article:
Quote
Using an inter-calibrated satellite sea ice product, this article examines the sensitivity of decadal trends of Arctic sea ice extent and statistical projections of the first occurrence of an ice-free Arctic summer. The projection based on the linear trend of the last 20 years of data places the first Arctic ice-free summer year at 2036, 12 years earlier compared to that of the trend over the last 30 years. The results from a sensitivity analysis of six commonly used curve-fitting models show that the projected timings of the first Arctic ice-free summer year tend to be earlier for exponential, Gompertz, quadratic, and linear with lag fittings, and later for linear and log fittings. Projections of the first Arctic ice-free summer year by all six statistical models appear to converge to the 2037 ± 6 timeframe, with a spread of 17 years, and the earliest first ice-free Arctic summer year at 2031.

Nice  :)

I like this extract from the conclusions:
Quote
The most persistently probable curve-fit model from all the methods examined appears to be Gompertz, even if it is not the best of the subset for all analyzed periods.
Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 23, 2018, 10:04:56 PM
One of the weaknesses with just projecting from recent trends is that the natural variability inherent in the climate system could be missed.  For example, it's estimated that the Atlantic Multidecadal Oscillation (AMO) and the Pacific Decadal Oscillation (PDO) both influence the transport of heat from the tropics to the Arctic.  Recent studies estimate that natural variability is responsible for 30% to 50% of the recent losses in Arctic sea ice are due to natural variability.

Some studies are showing that the AMO is shifting from a positive phase, as it has been since the 1990s, to a negative phase.  During a positive phase of the AMO, more warm Atlantic water is transported to the Arctic than during a negative phase.  This could lead to a slow-down in the loss rates of the Arctic sea ice, which wouldn't be captured by projecting trends.

Here's an article explaining the link between the AMO and Arctic sea ice:  http://adsabs.harvard.edu/abs/2016EGUGA..18.1978D (http://adsabs.harvard.edu/abs/2016EGUGA..18.1978D)

Here's the abstract:
Quote
The Arctic and North Atlantic have experienced pronounced changes over the 20th and early 21st centuries, including a rapid loss of Arctic sea ice over the last several decades, prominent multidecadal variability in both ocean temperatures and sea ice, and decadal-scale change in tropical storm activity. We use suites of coupled climate model simulations to probe some of the factors responsible for the observed multidecadal variability in the Atlantic/Arctic system. In our models we show that multidecadal fluctuations of the North Atlantic Oscillation (NAO) induce multidecadal fluctuations of the Atlantic Meridional Overturning Circulation (AMOC). A positive phase of the NAO is associated with strengthened westerly winds over the North Atlantic. These winds extract more heat than normal from the subpolar ocean, thereby increasing upper ocean density, deepwater formation, and the strength of the AMOC and associated poleward ocean heat transport. In model simulations the observed negative phase of the NAO in the 1960s and 1970s led to a weaker than normal AMOC, reduced poleward ocean heat transport, a cold North Atlantic, and an increase in Arctic sea ice extent in both winter and summer. The NAO strengthened from the 1970s to the mid 1990s, leading to an increase of the AMOC and a warming of the North Atlantic. The increased heat transport extended throughout the North Atlantic, into the Barents Sea, and finally into the Arctic, contributing to a rapid reduction of sea ice in the 1990s through the 2000s. Feedbacks involving shortwave radiation are an important component of the overall changes. The NAO-induced AMOC increase also led to hemispheric-scale atmospheric circulation changes and increased Atlantic hurricane activity, as well as atmospheric teleconnections to the Southern Ocean. Since the mid 1990s the strong positive phase of the NAO has weakened to a more neutral phase. Climate projections for the next decade that take into account recent behavior of the NAO as well as anthropogenic radiative forcing suggest a weakening of the AMOC and associated ocean heat transport, which would tend to moderate the rate of Arctic sea ice loss over the next decade. This effect is superimposed on the persistent and growing effects of anthropogenic climate change.

And here's another article about the possibility of a slow down in the sea ice loss: http://www.pnas.org/content/112/15/4570 (http://www.pnas.org/content/112/15/4570)

Abstract: 
Quote
Satellite observations reveal a substantial decline in September Arctic sea ice extent since 1979, which has played a leading role in the observed recent Arctic surface warming and has often been attributed, in large part, to the increase in greenhouse gases. However, the most rapid decline occurred during the recent global warming hiatus period. Previous studies are often focused on a single mechanism for changes and variations of summer Arctic sea ice extent, and many are based on short observational records. The key players for summer Arctic sea ice extent variability at multidecadal/centennial time scales and their contributions to the observed summer Arctic sea ice decline are not well understood. Here a multiple regression model is developed for the first time, to the author’s knowledge, to provide a framework to quantify the contributions of three key predictors (Atlantic/Pacific heat transport into the Arctic, and Arctic Dipole) to the internal low-frequency variability of Summer Arctic sea ice extent, using a 3,600-y-long control climate model simulation. The results suggest that changes in these key predictors could have contributed substantially to the observed summer Arctic sea ice decline. If the ocean heat transport into the Arctic were to weaken in the near future due to internal variability, there might be a hiatus in the decline of September Arctic sea ice. The modeling results also suggest that at multidecadal/centennial time scales, variations in the atmosphere heat transport across the Arctic Circle are forced by anticorrelated variations in the Atlantic heat transport into the Arctic.

None of this is to deny the impact of greenhouse gas emissions and the warming climate.  If we don't reduce are emissions and lower the concentrations in the atmosphere, the Arctic will eventually become ice free.  It's just a question of how soon.
Title: Re: Ice-free Arctic
Post by: Archimid on March 23, 2018, 10:08:14 PM
Quote
Projections of the first Arctic ice-free summer year by all six statistical models appear to converge to the 2037 ± 6 timeframe, with a spread of 17 years, and the earliest first ice-free Arctic summer year at 2031.

I can certainly agree that 2037 is a very good fit for the data. That's an earlier date than what I got in the calculations above using volume maximum and average losses. Sadly, such prediction is vulnerable to things like GAC's, strong el niños, changes in atmospheric and ocean circulations and unknowns of large magnitude.

Once 0 ice is hit the trends won't matter because it will be a different system. But that is a different argument all together. Now all we need is a coupled model that predicts the Arctic gone by 2037. If such model predicts that the ice will recover after the first ice free Arctic I would be surprised but very happy because chances are I'm wrong about an irreversible state change.
Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 23, 2018, 10:21:30 PM
Quote
...  because chances are I'm wrong about an irreversible state change

I'm glad you're open to new information.  Here's something you may be happy to read:

https://journals.ametsoc.org/doi/pdf/10.1175/JCLI-D-14-00654.1 (https://journals.ametsoc.org/doi/pdf/10.1175/JCLI-D-14-00654.1)

Abstract: 
Quote
Record lows in Arctic sea ice extent have been making frequent headlines in recent years. The change in
albedo when sea ice is replaced by open water introduces a nonlinearity that has sparked an ongoing debate
about the stability of the Arctic sea ice cover and the possibility of Arctic ‘‘tipping points.’’ Previous studies
identified instabilities for a shrinking ice cover in two types of idealized climate models: (i) annual-mean
latitudinally varying diffusive energy balance models (EBMs) and (ii) seasonally varying single-column
models (SCMs). The instabilities in these low-order models stand in contrast with results from comprehensive
global climate models (GCMs), which typically do not simulate any such instability. To help bridge
the gap between low-order models and GCMs, an idealized model is developed that includes both latitudinal
and seasonal variations. The model reduces to a standard EBM or SCM as limiting cases in the parameter
space, thus reconciling the two previous lines of research. It is found that the stability of the ice cover vastly
increases with the inclusion of spatial communication via meridional heat transport or a seasonal cycle in
solar forcing, being most stable when both are included. If the associated parameters are set to values that
correspond to the current climate, the ice retreat is reversible and there is no instability when the climate is
warmed. The two parameters have to be reduced by at least a factor of 3 for instability to occur. This implies
that the sea ice cover may be substantially more stable than has been suggested in previous idealized
modeling studies.

Here's a plain language summary of the article: https://scripps.ucsd.edu/news/research-highlight-arctic-sea-ice-loss-likely-be-reversible (https://scripps.ucsd.edu/news/research-highlight-arctic-sea-ice-loss-likely-be-reversible)

Quote
Research Highlight: Arctic Sea Ice Loss Likely To Be Reversible
   
Scenarios of a sea ice tipping point leading to a permanently ice-free Arctic Ocean were based on oversimplified arguments

New research by Till Wagner and Ian Eisenman, scientists at Scripps Institution of Oceanography, UC San Diego, resolves a long-running debate over irreversible Arctic sea ice loss.

Ever since the striking record minimum Arctic sea ice extent in 2007, the ominous scenario of a sea ice tipping point has been a fixture in the public debate surrounding man-made climate change and a contingency for which Arctic-bordering countries have prepared.

For decades, scientists have been concerned about such a point of no return, beyond which sea ice loss is irreversible. This concern was supported by mathematical models of the key physical processes (known as process models) that were believed to drive sea ice changes. The process models forecasted that increased global warming would push the Arctic into an unstoppable cascade of melting that ceases only when the ocean becomes ice-free.

...

Wagner and Eisenman resolve this discrepancy in the study in an upcoming Journal of Climate article,  “How Climate Model Complexity Influences Sea Ice Stability.”

They created a model that bridged the gap between the process models and the GCMs, and they used it to determine what caused sea ice tipping points to occur in some models but not in others.

“We found that two key physical processes, which were often overlooked in previous process models, were actually essential for accurately describing whether sea ice loss is reversible,” said Eisenman, a professor of climate dynamics at Scripps Oceanography. “One relates to how heat moves from the tropics to the poles and the other is associated with the seasonal cycle. None of the relevant previous process modeling studies had included both of these factors, which led them to spuriously identify a tipping point that did not correspond to the real world.”

“Our results show that the basis for a sea ice tipping point doesn’t hold up when these additional processes are considered,” said Wagner. “In other words, no tipping point is likely to devour what’s left of the Arctic summer sea ice. So if global warming does soon melt all the Arctic sea ice, at least we can expect to get it back if we somehow manage to cool the planet back down again.”
Title: Re: Ice-free Arctic
Post by: Archimid on March 23, 2018, 10:40:25 PM
Quote
One of the weaknesses with just projecting from recent trends is that the natural variability inherent in the climate system could be missed.  For example, it's estimated that the Atlantic Multidecadal Oscillation (AMO) and the Pacific Decadal Oscillation (PDO) both influence the transport of heat from the tropics to the Arctic.  Recent studies estimate that natural variability is responsible for 30% to 50% of the recent losses in Arctic sea ice are due to natural variability.

That was discussed at some depth here:
https://forum.arctic-sea-ice.net/index.php/topic,1920.0.html

My take after the discussion? Natural variability has been dead a long time ago. Others disagreed with excellent reasons.

Quote
Some studies are showing that the AMO is shifting from a positive phase, as it has been since the 1990s, to a negative phase.  During a positive phase of the AMO, more warm Atlantic water is transported to the Arctic than during a negative phase.  This could lead to a slow-down in the loss rates of the Arctic sea ice, which wouldn't be captured by projecting trends.

I agree that might help a bit. It doesn't appear it was much help during the 80's but still, lower sst's are lower sst's. Sadly, low sst after the last few decades of warming may look like a high sst of the beginning of the 20th century. We'll see in about a decade it seems.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.climate4you.com%2Fimages%2FAMO%2520DetrendedGlobalAnnualIndexSince1856%2520With11yearRunningAverage.gif&hash=c4c002aa1533130cd91b54f3761bc22a)

Quote
If the ocean heat transport into the Arctic were to weaken in the near future due to internal variability, there might be a hiatus in the decline of September Arctic sea ice.

We are betting our world on "if's". Bad bad bets.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 23, 2018, 11:02:22 PM
If the AMO is a major player, then the ice would be expected to be higher in the 1980s, as the AMO was negative.  The AMO turned positive in 1996, around the same time that the ice started it’s precipitous decline.  Base on the graph, the AMO appears to have peaked in the mid 2000s, and been flat since.  There is a correlation, maybe there is causation also.
Title: Re: Ice-free Arctic
Post by: Archimid on March 23, 2018, 11:48:11 PM
Quote
I'm glad you're open to new information.  Here's something you may be happy to read:

Of course, that's why I'm here. Regrettably, your link doesn't say what I want to hear.  From a quick read the gist of that article is that if we lower CO2, thus cooling the planet, the ice will return. I can certainly agree with that as the ice has been gone before and returned. But that is not my concern at all. I'm 100% sure the Arctic ice will return when milankovitch cycles say so or CO2 is reduced.

My concern is that there is no reason to think that CO2 levels will be reduced or global warming stopped. None. So if the warming is not reduced there is no reason to think that summer ice and most of the winter ice will return after the first ice free arctic.

The fact that the model you linked assumes an "aquaplanet" cements it for me that that model is not an accurate representation of the climate system anyway. Just a useful idealization, so it says nothing about the impact of an ice free arctic in the real world.
Title: Re: Ice-free Arctic
Post by: Archimid on March 23, 2018, 11:51:26 PM
If the AMO is a major player, then the ice would be expected to be higher in the 1980s, as the AMO was negative.  The AMO turned positive in 1996, around the same time that the ice started it’s precipitous decline.  Base on the graph, the AMO appears to have peaked in the mid 2000s, and been flat since.  There is a correlation, maybe there is causation also.

The AMO was a major player, but global warming might have already overwhelmed the signal of the AMO. Today's negative AMO is yesterdays positive AMO. Today's positive AMO is super positive in terms of actual SST's, not the anomalies.

(https://climatedataguide.ucar.edu/sites/default/files/styles/node_lightbox_display/public/key_figures_427?itok=-sPaMY5C)
Title: Re: Ice-free Arctic
Post by: jai mitchell on March 24, 2018, 04:07:40 PM
Anthropogenic aerosols in the Arctic have their strongest impact in Spring.  Reductions of sulphate aerosol emissions between 1980-2010 are responsible for 1/4 of the total warming there.  Warming in the early spring melt season is the strongest factor determining end of season minimum sea ice levels.

http://acmg.seas.harvard.edu/publications/2017/breider_decadal_arctic_2017.pdf

Quote
Anthropogenic sulfate in our study yields more strongly negative forcings over the Arctic troposphere in spring (-1.17 ± 0.10 W m^2 ) than previously reported. From 1980 to 2010, TOA negative RF by Arctic aerosol declined, from -0.67 ± 0.06 W m^2 to -0.19 ± 0.05 W m^2, yielding a net TOA RF of +0.48 ± 0.06 W m^2. The net positive RF is due almost entirely to decreases in anthropogenic sulfate loading over the Arctic. We estimate that 1980–2010 trends in aerosol-radiation interactions over the Arctic and Northern Hemisphere midlatitudes have contributed a net warming at the Arctic surface of +0.27 ± 0.04 K, roughly one quarter of the observed warming.

However, the total warming in the Arctic associated with a complete reduction of Sulphate Aerosol emissions derived from the models that most accurately include this factor indicate that a complete reduction in Sulphate Aerosols will increase Arctic temperatures between 2C and 4C on an annual average.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017GL076079#grl56865-supitem-0001

see supplementary images of the models used (images S2-S5): (example below) https://agupubs.onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1002%2F2017GL076079&attachmentId=2186427861

Therefore, the Arctic is currently being bolstered significantly from air pollution, the last 30-years of reductions in air pollution emissions have been responsible for much of the sea ice loss during the satellite era and the exact date of ice-free Arctic is strictly dependent on what we do going forward WRT to these aerosols.  This is an observed function of direct Arctic geoengineering that we are doing today.





Title: Re: Ice-free Arctic
Post by: gerontocrat on March 24, 2018, 04:56:54 PM

Use enough parameters and you can fit the data and have the extrapolation going wherever you want it to. By selecting this curve type for my fit, I am insisting it goes horizontal at some point, but if it resulted in a better fit this could be year 1,000,000 or later. I don't really believe the data extrapolation should go horizontal, it should still be downwards. However it it useful to see where and what level it levels out at and the answer is soon and high. All models are wrong but some are useful.
Lies, damned lies and statistics.

I attach two graphs. The data is the same and is direct from the NSIDC spreadsheets.

One shows winter sea ice dropping like a stone, the other gently going down. The polynomial trend line on the Armageddon graph has a better R2 value than the linear trendline. For me the graphs do show one thing - and only one thing - the range of possibilities in the years ahead.

To use them as any proof of anything is just not on..


Title: Re: Ice-free Arctic
Post by: crandles on March 24, 2018, 05:27:20 PM
Yes absolutely.

The horizontal trend is a result of the gompertz curve selected. I have said it repeatedly that I don't believe that, it will continue downwards.

The useful part I was referring to was as a test of whether the steep part of the curve had started to level out. This is about the past not the future.

Even then just the curve is not enough. Had there only be 3 or 4 data points past the inflection then it would be appropriate to conclude the curve was overfitting taking advantage of random variations in the last 3 or 4 years. With 5 or 6 years past the inflection, that should still be considered a possibility, but with 11 years past the inflection (think 11 heads from 11 coin tosses), the possibility seems remote.

This of course doesn't mean the trend can't accelerate again.
(But with data not showing it, and literature providing explanation for acceleration and deceleration, you would need a good physical explanation for speculating on a new acceleration being expected when essentially none of the models show it.)
Title: Re: Ice-free Arctic
Post by: Paddy on March 24, 2018, 06:30:38 PM
We're trying to project a description of a complex phenomenon well beyond our data, and should be cautious in whatever we predict. I remember in 2012 I was worried we might well be dropping off a cliff with a sharp acceleration in ice loss, but luckily that hasn't actually happened, or at least not to anything like the extent I feared. Yet.
Title: Re: Ice-free Arctic
Post by: Archimid on March 24, 2018, 07:01:37 PM
The linear trend is going down. The same is true for the trend of the linear trends.

What can possibly slow down/reverse the trends?

1. Clouds: Clouds warm the Arctic during the Arctic night and but cool the Arctic during summer. If the cooling power of clouds is greater than the warming power of clouds, the total impact of clouds is a negative feedback. Any work addressing the total annual impact of clouds in the Arctic? I did a quick read of 3 of them. All of them conclude that clouds probably result in net warming. Here is one with a nice, concise conclusion:

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2000JD900043

Quote
If climate change were to bring more low clouds to the Arctic, ice thickness should increase due to the increased energy loss from the Arctic climate system. However, the added atmospheric cooling by low clouds would probably increase the poleward energy flux from the midlatitudes, reducing the increase in ice thickness. An increase in high clouds would decrease Arctic ice thickness by reducing the loss of energy by the surface-atmosphere system. The enhanced atmospheric warming of high clouds probably would decrease the poleward energy flux and slightly offset the reduction in ice thickness. The general understanding of the role of clouds in the Arctic climate will be greatly improved by reliable observational estimates of cloud radiative forcing as a function of cloud type and season.


2.  Snow cover. If the WACCy pattern becomes the norm, then it is reasonable to assume a negative feedback due to albedo changes. So far, snow has significantly increase in thickness but extent has dropped significantly in spring, increased significantly in fall and increased slightly in winter. The effect of the increased snow hasn't slowed down the trends. Maybe at some point it will.

https://climate.rutgers.edu/snowcover/chart_seasonal.php?ui_set=nhland&ui_season=2

3. Natural Cycles. The big three natural temperature cycles that I know about are the AMO, the PDO and ENSO. In 2016 all three of those cycles were positive, which got us the hottest year on record. The last 2 ENSO was negative. Temperatures remain high. The trends kept marching down.

The following graph shows the PDO, the AMO and global temperatures. ENSO not available in the site, but it doesn't matter.

http://woodfortrees.org/graph/gistemp/scale:150/offset:-500/from:1980/plot/jisao-pdo/scale:50/offset:-50/from:1980/plot/esrl-amo/scale:200/offset:-250/from:1980

It seems that during a -AMO and -PDO cycle the most we can hope for is a hiatus in global temps.  That might or might not translate to a hiatus in Arctic temperatures.  The trend can indeed slow down for a few years or even decades. Sadly GHG's ensure the temperatures won't cool enough to reverse the trend.

4.  Solar cycles. Yeah I know this is a extremely small forcing, but it is so constant in its periodicity and so global and so steady for so long that I can't convince myself that it doesn't matter. It might not matter for global temperatures as the data clearly shows that solar has been  in the decline for 5 decades and temperatures really don't seem to care, but it must matter for something.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwoodfortrees.org%2Fgraph%2Fsidc-ssn%2Ffrom%3A1900&hash=0a113d96368983cd2ec7e9b0d750d9d2)


So what am I missing that the GCM's see to reverse the trends?
Title: Re: Ice-free Arctic
Post by: Archimid on March 24, 2018, 07:13:52 PM
We're trying to project a description of a complex phenomenon well beyond our data, and should be cautious in whatever we predict.

That is exactly why makes this so darn scary. No one really knows but everyone is pretending that it will all be just fine without knowing is that is true or not. Given the uncertainty in both the date and possible consequences of a blue ocean event, there should be an all out effort to:

1. Invest in all resources necesary to find out if, when and how the BOE is happening
2. Prepare humanity for it.

I wish I was exaggerating and being alarmist but all the evidence I find tells me I'm not. An ice free Arctic is the biggest threat humanity has ever faced.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 24, 2018, 07:50:39 PM
We're trying to project a description of a complex phenomenon well beyond our data, and should be cautious in whatever we predict.

That is exactly why makes this so darn scary. No one really knows but everyone is pretending that it will all be just fine without knowing is that is true or not. Given the uncertainty in both the date and possible consequences of a blue ocean event, there should be an all out effort to:

1. Invest in all resources necesary to find out if, when and how the BOE is happening
2. Prepare humanity for it.

I wish I was exaggerating and being alarmist but all the evidence I find tells me I'm not. An ice free Arctic is the biggest threat humanity has ever faced.

Actually, I think you are.  While they is a real probability that an ice-free Arctic could happen soon (<10 years), there is a similar probability that it will not happen for a long time.  I understand that you want to alert others to this possibility, but I think you are over-estimating how soon it will occur.  Secondly, your last statement is conjecture.  The consequences of an ice-free Arctic are not known.  Saying that it is “the biggest threat that humanity has ever faced,” sure sounds alarmist.
Title: Re: Ice-free Arctic
Post by: gerontocrat on March 24, 2018, 08:50:42 PM
Quote
It seems that during a -AMO and -PDO cycle the most we can hope for is a hiatus in global temps.  That might or might not translate to a hiatus in Arctic temperatures.  The trend can indeed slow down for a few years or even decades. Sadly GHG's ensure the temperatures won't cool enough to reverse the trend.

Temperatures as in Atmospheric Temperatures.

But CO2 ppm will continue to increase. More heat is trapped.
Where does it go? The oceans.
Does some of that extra heat go North (and South) eventually? Yes.
Is that process slower than movement of heat through the atmosphere? yes.

So Choose - death of Arctic Ice by a 1,000 cuts or by 100 cuts?

Title: Re: Ice-free Arctic
Post by: Archimid on March 25, 2018, 04:06:27 AM
Quote
Actually, I think you are.

Of course you do. I already gave you the scientific explanation for that. It is too scary for you to handle, so your brain plays tricks on you to protect your emotional health leading you to denial.

I know this is mean but I believe that is the scientific truth that explains how you can ignore the dangers. Is either that or ignorance. You may or may not have that excuse, Dr. Curry doesn't. I know is real because even as I'm saying this I don't want to believe it is true. In fact I spend a good portion of my day trying to avoid thinking of this and pretending it is not happening. This whole global warming nightmare has a very detrimental effect on my health. I perfectly understand why anyone would try to avoid it like a plague.

Quote
While they is a real probability that an ice-free Arctic could happen soon (<10 years), there is a similar probability that it will not happen for a long time.

Define long time. If by long time you mean 20 years, then I have no option but to agree, but only because the trends must be acknowledged.  The probability that it happens much later than 2037 is much lower than for it to happen sooner because of the small detail of global warming.

Quote
The consequences of an ice-free Arctic are not known. Saying that it is “the biggest threat that humanity has ever faced,” sure sounds alarmist.

No, the consequences are not known but that uncertainty is reason for extreme concern not complacency. This is extremely concerning by virtue of the centrality of the Arctic to the North Hemisphere, the longevity of the Arctic sea ice in the current state of the climate system and the surface area of the Arctic relative to the world. Arctic sea ice is a BIG deal(and thats a huge understatement). That alone, without knowing anything else is reason for extreme concern.

To estimate the danger the key is understand that the Arctic is ice stored during winter that the climate system uses in the summer normalizing the climate throughout the year.

If the ice is not there during the summer solstice the Arctic will receive more power from the sun than the tropics. It will get EXTREMELY warm. It doesn't get warm now only because there is ice left to be consumed by the sun. I think a good way to visualize it is with the n80 temperatures graph:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Focean.dmi.dk%2Farctic%2Fplots%2FmeanTarchive%2FmeanT_2016.png&hash=ed3bc1964e488b5d83cfae05c243a1bc)

Why the large variability in winter but extremely low variability in summer? The summer temperatures near the surface are dictated by the ice. If the ice wasn't there the N80 temps graph would not have the top shaved off, instead it would follow a shape similar of solar insolation above 80:

(https://yukongreenhouse.weebly.com/uploads/1/0/5/2/10529729/7324155.jpg?614)

Do you think that can destabilize the climate? If you say no please give some evidence or at least a reasonable explanation, because that would be an extraordinary claim. 

That is reason to sound the loudest alarms possible so that everyone can get ready and maybe, if we try hard enough, even stop it.

I sound alarmist because that is the only possible way to tell you the truth. I can lie to you and not alarm you, but that would be a lie. A comfortable lie for both you and me, but literally deadly lie. The truth is that there is climate emergency going on. It is likely that extreme weather keep rising until a BOE, then after the BOE the Earth will be a different planet at least until a new form of climate stability is reached.

Title: Re: Ice-free Arctic
Post by: Daniel B. on March 25, 2018, 06:13:48 AM
No, the extraordinary claim is that the climate will be destabilized.  You are confusing truth with your own opinion.  Not that it could never happen.  It is not impossible.  I do not disagree with your predictions, just because they are scary.  No, I disagree because they are unsupported by the evidence.  Your ad hominem attacks will not sway my thinking.  Only scientific evidence will do so.  As many other posters have stated, the Arctic is a chaotic system with many factors affecting the outcomes, and consequently, making predictions are quite difficult.  Therefore, making the extraordinary claim of an ice-free Arctic in less than a decade, requires extraordinary evidence to go against the current trend.

I know many people fear uncertainty.  That is quite normal.  We become comfortable in our knowing.  However, claiming that uncertainty means danger, is a rather pessimistic view.  By your posts, I believe you are truly alarmed.  However, you have yet to convince that I should be alarmed.
Title: Re: Ice-free Arctic
Post by: Sleepy on March 25, 2018, 08:11:31 AM
Quote
Only scientific evidence will do so.
A thought is 98% unconscious. We can only understand what our brains allow us to understand. If you belive in science, you've gotta belive that too.

https://youtu.be/KzGgIDEAAG0
Title: Re: Ice-free Arctic
Post by: El Cid on March 25, 2018, 09:58:43 AM
We could have possibly lost much of the summer ice during the Holocene climatic optimum and the Eemian. Still, it did not lead to runaway instabilization of the global climate. An ice-free (summer/autumn) Arctic would definitely lead to much warmer temperatures in the Arctic and possibly warmer temperatures in the (NH) midlatitudes. It could possibly lead to atmospheric circulation changes which could enforce or weaken the warming. There are just too many unknowns but Daniel B is right: there is no scientific evidence that such a new state would lead to collapse and chaos.
Climate models projecting 2100 temperatures show 3-6 degree warming in NH midlatitudes. That includes all the emissions till 2100 AND an ice-free Arctic. So if the Arctic goes ice-free by 2030 (and it might) I think the scientific opinion is that NH midlatitude temps will be 1-3 degrees above baseline, which is a lot but definitely won't lead to collapse.

Mind you, I believe that climate change is a very serious long term (meaning 50-100 yrs) threat but I do not think that it will cause systemic problems in 10-20 years even if we lose summer ice and I think that opinion is unsupported by facts.
Title: Re: Ice-free Arctic
Post by: Avalonian on March 25, 2018, 10:41:08 AM
Fascinating as this thread is, there's obviously little common ground in what will actually happen. My gut feeling is very similar to Archimid's take on it, but clearly other people don't see it the same way, no matter how much that might jar with my sense of reality. So, can we actually find things to agree on, and build up from there?

I can see there's not going to be universal agreement on likely timing until a BOE actually happens. But if the next two or three years sees another massive record (in the style of 2012 but more severe still), will that be enough to accept that the decline is not slowling down? Conversely, hat outcomes in the next 3 years would be enough to change your mind, from either side?
     Personally, I fully expect to see a new record soon, but I'm also willing to believe that some negative feedbacks are now slowing the process. If it reverts to around 2013-4 levels and stays there over the next few years, I might even start to wonder about that Gompertz fit...  ;)

Now let's assume that we do get an ice-free Arctic at some point (unspecified, but not too far away). Are we all agreed that this means that Arctic summer temperatures will rise dramatically above zero, to an extent depending on the length of time the ice is gone for?
Title: Re: Ice-free Arctic
Post by: Gray-Wolf on March 25, 2018, 11:34:59 AM

Now let's assume that we do get an ice-free Arctic at some point (unspecified, but not too far away). Are we all agreed that this means that Arctic summer temperatures will rise dramatically above zero, to an extent depending on the length of time the ice is gone for?

I think there are a number of us waiting to see the DMI 80N plot leave the 'latent heat of fusion' dictated summer temps to its first spike well above freezing ( 2 or 3 degrees?) as the floes thin out and open water exceeds ice covered?

I think the very end of 2016 melt season did see ( with the eye of the faithful) an uptick at the very end of the 'pinned to zero' period of the DMI 80N

With low peripheries again there is a chance for an early break up of the central pack and then drift may lead to an open central polar area and again a chance to see 'lift off' of the temp line on the DMI plot!
Title: Re: Ice-free Arctic
Post by: El Cid on March 25, 2018, 12:51:46 PM


Now let's assume that we do get an ice-free Arctic at some point (unspecified, but not too far away). Are we all agreed that this means that Arctic summer temperatures will rise dramatically above zero, to an extent depending on the length of time the ice is gone for?

I think that when we lose all summer ice it will happen in August/September, not before, so Arctic temperatures will not be able to go up (due to the coming polar night and the still cold sea), instead they will just refuse to go significantly down in Sep-Oct, and and stay very high until Nov/Dec whent the Arctic will refreeze.

I believe that for Arcic temperatures to go up significantly by August, we would need to see a comlete meltout by June, but that is probably not on the cards for now.

So my take is that Sep-Nov  (Dec) temps will be drastically higher but not summer temps. What changes this will cause to atmospheric circulation - i have no idea...
Title: Re: Ice-free Arctic
Post by: crandles on March 25, 2018, 12:59:50 PM
Quote
Actually, I think you are.
Of course you do. I already gave you the scientific explanation for that. It is too scary for you to handle, so your brain plays tricks on you to protect your emotional health leading you to denial.
You do realise we can easily counter that you are concentrating of this subject, so you have vested interest in it being important, 'so your brain plays tricks on you to protect your emotional health leading you to denial'?
So this doesn't work well as an argument.

.

Define long time. If by long time you mean 20 years, then I have no option but to agree, but only because the trends must be acknowledged.  The probability that it happens much later than 2037 is much lower than for it to happen sooner because of the small detail of global warming.

We agree that global warming is not a small detail, but for such a statement you need some quantification which appears completely missing in this paragraph.

The trends are the least of the science. Far more important there are lots of models with lots of different dates for ice free but generally 2040 or later. Given this poor agreement, they might all be saying later than reality. However, they are all showing a slow down in the rate of loss as ice free is approached. When there is such solid agreement on that, and the data also shows it then this looks fairly solid but still not 100% so there is still a small chance of being in next 10 years but I would suggest the vast majority of the probability is for 2037 or later.

Above personal opinion means little. It does however appear to recognise more of the science than you are doing.
Title: Re: Ice-free Arctic
Post by: crandles on March 25, 2018, 01:22:34 PM

Now let's assume that we do get an ice-free Arctic at some point (unspecified, but not too far away). Are we all agreed that this means that Arctic summer temperatures will rise dramatically above zero, to an extent depending on the length of time the ice is gone for?

No. The first time it happens will probably be before the trend reaches ice free.

I agree with El Cid that it will be late in the season. Some extra warmth will be accumulated by mid September. However during fall this will get vented to the atmosphere. (less ice less insulation)

I go further than El Cid:
The delay before ice forms solidly enough to collect snow won't be very long but this is the snow season. The lack of snow cover on the ice means less insulation so more heat continues to be lost to the atmosphere during winter. The result is thicker ice cover than usual for that period at the next maximum. Less snow might cause slightly earlier melt onset but these effects dissipate and things will probably be back on trend about 2 years after the ice free event.

(Probably - I admit some risk of weird weather effects meaning it doesn't play out as models suggest.)
Title: Re: Ice-free Arctic
Post by: Alexander555 on March 25, 2018, 02:45:41 PM

Now let's assume that we do get an ice-free Arctic at some point (unspecified, but not too far away). Are we all agreed that this means that Arctic summer temperatures will rise dramatically above zero, to an extent depending on the length of time the ice is gone for?

No. The first time it happens will probably be before the trend reaches ice free.

I agree with El Cid that it will be late in the season. Some extra warmth will be accumulated by mid September. However during fall this will get vented to the atmosphere. (less ice less insulation)

I go further than El Cid:
The delay before ice forms solidly enough to collect snow won't be very long but this is the snow season. The lack of snow cover on the ice means less insulation so more heat continues to be lost to the atmosphere during winter. The result is thicker ice cover than usual for that period at the next maximum. Less snow might cause slightly earlier melt onset but these effects dissipate and things will probably be back on trend about 2 years after the ice free event.

(Probably - I admit some risk of weird weather effects meaning it doesn't play out as models suggest.)

The problem is that what you explain here ,is what is happening already for a long time. The area with less or no  ice is already getting bigger for dozens of years. So it looks like the heat that is escaping is warming the Arctic. It's not making the ice thicker, we lost 75 % of the summer ice. Probably because the ocean stores more and more heat every year. And in some way you could say that it will only release that heat if the air above it is colder. If that point moves further north, it will hold that heat until it's further north.
Title: Re: Ice-free Arctic
Post by: gerontocrat on March 25, 2018, 03:57:02 PM

Now let's assume that we do get an ice-free Arctic at some point (unspecified, but not too far away). Are we all agreed that this means that Arctic summer temperatures will rise dramatically above zero, to an extent depending on the length of time the ice is gone for?

No. The first time it happens will probably be before the trend reaches ice free.

I agree with El Cid that it will be late in the season. Some extra warmth will be accumulated by mid September. However during fall this will get vented to the atmosphere. (less ice less insulation)


I was looking at albedo and Archimid pointed me to a lovely piece of work by Tealight and Nico Sun.

In the 2012 Arctic spring, sea ice was comparatively high, very high, compared with other years in the 2010's. Then relatively late the big collapse came.

In 2016, sea ice loss started really early, but then became sort of average, with sea ice minimum hundreds of thousands of km2 greater than 2012.

And despite that 2016 cumulative albedo warming potential for the year is higher by far than 2012.

i.e.A low winter maxima and early melt is the most effective way to heat up the Arctic ocean.
A late melting don't cut it.
Title: Re: Ice-free Arctic
Post by: Sleepy on March 25, 2018, 04:23:43 PM
I was looking at albedo and Archimid pointed me to a lovely piece of work by Tealight and Nico Sun.
Don't want to interfere here, but Nico Sun is Tealight.
Title: Re: Ice-free Arctic
Post by: gerontocrat on March 25, 2018, 05:09:16 PM
I was looking at albedo and Archimid pointed me to a lovely piece of work by Tealight and Nico Sun.
Don't want to interfere here, but Nico Sun is Tealight.
The original graph said it was by tealight and calcs by nico sun. Ho hum9
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 25, 2018, 05:50:24 PM
Fascinating as this thread is, there's obviously little common ground in what will actually happen. My gut feeling is very similar to Archimid's take on it, but clearly other people don't see it the same way, no matter how much that might jar with my sense of reality. So, can we actually find things to agree on, and build up from there?

I can see there's not going to be universal agreement on likely timing until a BOE actually happens. But if the next two or three years sees another massive record (in the style of 2012 but more severe still), will that be enough to accept that the decline is not slowling down? Conversely, hat outcomes in the next 3 years would be enough to change your mind, from either side?
     Personally, I fully expect to see a new record soon, but I'm also willing to believe that some negative feedbacks are now slowing the process. If it reverts to around 2013-4 levels and stays there over the next few years, I might even start to wonder about that Gompertz fit...  ;)

Now let's assume that we do get an ice-free Arctic at some point (unspecified, but not too far away). Are we all agreed that this means that Arctic summer temperatures will rise dramatically above zero, to an extent depending on the length of time the ice is gone for?

I think we can all agree that the Arctic sea ice is shrinking.  Beyond that, I am not sure.  We have vastly different views as to how fast, and when the Arctic might become ice-free.  Remember, ice-free is defined as less than 1 million sq. km, not zero.  The Arctic has been rather chaotic the last few years, more so than usual, making it very hard to establish the current trend, let alone anything long term.  Few scientists are claiming an ice-free state in less than 20 years.  However, even those that are estimating a longer time frame cannot rule out a shorter term option.  Neither can they rule out a much longer option.  Thomas, no has published a probability curve regarding when the Arctic might become ice-free.  But like everything that has random variables, there is the probability that it could happen sooner or later than expected, especially when trying to pinpoint a condition that has not occurred in eons.  I will agree that a near record low in a year or two would enough to accept that the decline is not slowing down.  Contrarily, another year or two (maybe three) should be enough for most to accept that it is slowing down.  As always, more years of data will lead to better analyses.

Your last question about Arctic summer temperatures rising dramatically seems to lack agreement here also.  As many posters have shown, summer temperatures in the Arctic have not deviated much (compared to winter temps.), despite losing a significant portion of the ice surface to open water.  It would seem reasonable to assume that more heat would be absorbed by the darker water, and I am surprised that summer temperatures have not risen.  However, that is but one factor influencing the Arctic, and may be overridden by others. 
Title: Re: Ice-free Arctic
Post by: Alexander555 on March 25, 2018, 06:20:47 PM
Daniel, for what reason are you saying it's slowing down ? Where do you see it slowing down ? The temperature anomolies are getting bigger and bigger.
Title: Re: Ice-free Arctic
Post by: crandles on March 25, 2018, 06:32:57 PM
Daniel, for what reason are you saying it's slowing down ? Where do you see it slowing down ? The temperature anomolies are getting bigger and bigger.

I'm guessing
"Contrarily, another year or two (maybe three) should be enough for most to accept that it is slowing down."
was referring to arctic sea ice volume.

Maybe he found my posts at #220 and #228 convincing.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 25, 2018, 06:47:00 PM
Daniel, for what reason are you saying it's slowing down ? Where do you see it slowing down ? The temperature anomolies are getting bigger and bigger.

Not temperature, but sea ice decline as show here and the graphs presented by crandles.

https://climate.nasa.gov/vital-signs/arctic-sea-ice/ (https://climate.nasa.gov/vital-signs/arctic-sea-ice/)
Title: Re: Ice-free Arctic
Post by: Alexander555 on March 25, 2018, 07:38:28 PM
I see, we have to wait and see where it goes. But the last year i have been paying attention to it a little more than normal. And so far almost the entire winter the temperature was 3 to 6 degree C above average at the arctic. With sometimes vast areas 20 to 30 degree C above average. And these anomalies are getting bigger , that means a less cold arctic . Only the last few weeks it was colder than average.

Yesterday we had something interesting in the news. About the fishing industry. All the spicies are moving north. The spicies they were catching in the south of Europe. They are now in their nets in the North-Sea, like ink-fish . And the fish from the North-Sea moves further to the north. That is all about temperature. Something big is going on.
Title: Re: Ice-free Arctic
Post by: Archimid on March 25, 2018, 07:41:02 PM
Now let's assume that we do get an ice-free Arctic at some point (unspecified, but not too far away). Are we all agreed that this means that Arctic summer temperatures will rise dramatically above zero, to an extent depending on the length of time the ice is gone for?
Some extra warmth will be accumulated by mid September. However during fall this will get vented to the atmosphere. (less ice less insulation)
i.e.A low winter maxima and early melt is the most effective way to heat up the Arctic ocean.
A late melting don't cut it.

I posted the comment chain because I believe this discussion is the crux of the matter. I agree with everything said, but I think that based on what you all agreed the conclusion is that after the first BOE there is a significant change. Here is why I think that:


Let's define the first Blue Ocean Event (BOE) as the moment in time there is 0 ice in the Arctic Ocean. Let's take the average September minimum volume as the day of the first BOE.  Let's suppose that ice growth begins on the same day of the BOE. Lets assume the same conditions of the last 11 years.

If starting from 0, the ice grows the same way it grew for the last 11 years, then we can expect an average maximum of 17.69 x 1000km3. The average losses during the same time are of  18.09 x 1000km3. The data points to no recovery after a BOE.

 Of course things are not so simple. I'm going to check my assumptions.

Quote
Let's suppose that ice growth begins on the same day of the BOE.

That's a very bad assumption because:

Quote
Some extra warmth will be accumulated by mid September. However during fall this will get vented to the atmosphere. (less ice less insulation)

 If that heat is vented to the atmosphere, the atmosphere warms delaying ice formation in an amount roughly proportional to the heat accumulated during the year and transferred into the atmosphere. The earlier the BOE happens the more heat is accumulated. Pushing the start of ice formation back, likely resulting in a lower maximum.

But it is not just the warmth accumulated in the Arctic Ocean what delays the date. If the current behavior of the atmospheric currents worsen, then warm air intrusions from the NH will likely further delay things.

Then there are waves. Ice will not form while there are large waves. I'm not sure of any mechanism to control waves other than the ice front. As the ice front grows the waves are pushed back allowing for more ice growth. Maybe ridiculous amounts of snow might do it.

I think it is the very least the beginning of ice formation will be delayed.


Quote
Lets assume the same conditions of the last 11 years.

That is also a bad assumption because there will be negative albedo changes, wavier jets streams coupling with humidity changes in the atmosphere above the Arctic Ocean, and changes in the currents of the Atlantic ocean. The conditions will probably be more different than the difference of the last 11 years from the time before.


Quote
If starting from 0, the ice grows the same way it grew for the last 11 years, then we can expect an average maximum of 17.69 x 1000km3.

Horrible assumption. In the Arctic ice begets ice. That means that when it starts growing the area of ice growth will be extremely small and requires exponential growth to match the speed at which the ice grew for the last 11 years. There is no physical problem with that except that it requires a cold atmosphere and a cold ocean.  From what we have seen in the last three freezing season there is not enough endogenous cold in the arctic to maintain the cold temperatures needed to generate large amounts of ice even now. After a several BOEs it will be much worse.

Quote
The average losses during the same time are of  18.09 x 1000km3.

A stupid assumption because there can't be less than 0 ice! You can't lose ice that is not there in the first place. Therefore negative ice must be converted to heat that is added to the system.


Quote
A late melting don't cut it.

Not the first time around, but after the first BOE, the next time around there will be a lot less ice, which will melt much sooner, pushing the date of the BOE earlier and earlier.

  The only way to stop it and reverse it is to remove heat from the system.
Title: Re: Ice-free Arctic
Post by: Alexander555 on March 25, 2018, 08:04:23 PM
I don't know if it fits the entire planet. But over here in Europe, the higher summer temperatures last a lot longer into the end of the year. It looks like the summer is expanding. But you don't have that difference at the end of the winter. There are a few  extremer cold peaks ( if you filter the data out) that happen later than average. But i think that's the result of that weaker Vortex. Spring itself moved 15 days forward in 20 years.
Title: Re: Ice-free Arctic
Post by: Tealight on March 25, 2018, 08:11:15 PM
I was looking at albedo and Archimid pointed me to a lovely piece of work by Tealight and Nico Sun.
Don't want to interfere here, but Nico Sun is Tealight.

How do you know? I might have different personalities that work together on a project  ;D

I haven't read the whole discussion in detail, but I agree that with gerontocrat that spring ice cover isn't very indicative for the September minimum. Even better than the total cumulative albedo is looking at the regional distribution. 2012 had a high albedo in spring in the periphery, but in the central Arctic albedo was very low over a very widespread area. Other record low years typically have 1-2 dominant areas of low albedo and then the heat just prevents refreezing in autumn.

(https://drive.google.com/uc?id=0B1HTR0ONiUmEclhhaEo2TUYyRTg&export=download)

I'm not joining the discussion of what we define as ice-free, because it depends on your application. It's different for shipping, polar bears, ocean heat accumulation, ....


Btw: For the start of the 2018 melt season I calculated the cumulative AWP for years back to 1988. I fear before 1988 the much larger pole hole would violate data consistency. Some years are very interesting. 1990 has the record low albedo in the east Siberian sea, beating even 2007. 1998 had very low albedo on the entire american side and really high on the asian side.

https://sites.google.com/site/cryospherecomputing/warming-potential

(https://drive.google.com/uc?id=10fGnpFSqHSEoagqn1Is0iQBeEK_L69VV&export=download)
(https://drive.google.com/uc?id=1G-Pq4tm9fT9HUHTq2PtBJr-hn65CKhmO&export=download)
(https://sites.google.com/site/cryospherecomputing/_/rsrc/1521985001090/warming-potential/regional-graphs/AWP_anomaly_Regional_heatmap.png)
Title: Re: Ice-free Arctic
Post by: Alexander555 on March 25, 2018, 08:38:24 PM
Just to make sure that what i think is right. Because the term albedo is new for me. But it represents the capacity of an object  to reflect the sunlight, correct ? So a low albedo means the sunlight is not reflected, but used to melt the ice or to warm  the water. So that makes me think that all the red colour you see, reflects the bad condition of the ice, or the snow on top of it. Is that correct ?
Title: Re: Ice-free Arctic
Post by: oren on March 25, 2018, 08:42:30 PM
Archimid, thin ice gains volume much faster than thick ice during the cold of midwinter. That is a missing assumption in your argument.
Daniel B., I suggest to look at more graphs than just the headline trend of extent at minimum. For area we already had a near record low in 2016. Also look at volume at max and min. Look at the percent of old ice in the arctic. I think you may find that ice internals still point down when the main graph you are focusing on seems to be in a "hiatus". Just like ocean heat content continued building up when the deniers were claiming global warming has stopped based on the headline graph of global surface temps.
Title: Re: Ice-free Arctic
Post by: oren on March 25, 2018, 08:47:54 PM
Just to make sure that what i think is right. Because the term albedo is new for me. But it represents the capacity of an object  to reflect the sunlight, correct ? So a low albedo means the sunlight is not reflected, but used to melt the ice or to warm  the water. So that makes me think that all the red colour you see, reflects the bad condition of the ice, or the snow on top of it. Is that correct ?
When Tealight/Nico Sun calculates albedo-warming potential (very useful btw), he is dealing with the effect of open water albedo (compared to ice/snow-covered ice), multiplied by the insolation level on that date in that location. As far as I understand, he is not dealing with the state of the ice, the state of its snow cover, or the state of clear sky vs. cloudiness.
Title: Re: Ice-free Arctic
Post by: Archimid on March 25, 2018, 09:19:26 PM
thin ice gains volume much faster than thick ice during the cold of midwinter.

That is only true if the temperature holds constant for both thin and thick ice. But winter temperatures are not holding constant, they are rising significantly.

My argument is that the growth rate depicted here

(https://farm4.staticflickr.com/3824/9586307013_77132e9dd4_o.jpg)

is limited by temperatures

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=1611.0;attach=88074;image)

Yes it is completely true that thin ice thickens faster but  growth is limited by the temperatures. Since it is a fair assumption that Arctic temperatures after a BOE will be much higher than the past, then it is fair to assume that there will be much less ice growth.
Title: Re: Ice-free Arctic
Post by: Sleepy on March 25, 2018, 09:29:38 PM
I was looking at albedo and Archimid pointed me to a lovely piece of work by Tealight and Nico Sun.
Don't want to interfere here, but Nico Sun is Tealight.

How do you know? I might have different personalities that work together on a project  ;D

Only one person responded to my email when I asked about using your graphs. ;)
Title: Re: Ice-free Arctic
Post by: Shared Humanity on March 25, 2018, 09:42:19 PM
I was looking at albedo and Archimid pointed me to a lovely piece of work by Tealight and Nico Sun.
Don't want to interfere here, but Nico Sun is Tealight.

How do you know? I might have different personalities that work together on a project  ;D

Only one person responded to my email when I asked about using your graphs. ;)

That is the one with the more agreeable nature. You don't want to mess with the other one.  ::)
Title: Re: Ice-free Arctic
Post by: Tor Bejnar on March 25, 2018, 10:14:54 PM
One aspect of BOE not mentioned recently (last couple of days in this thread) is ocean water column mixing due to storms in ice-free areas.  As soon as the central Arctic gets well mixed, it won't freeze over during the winter, I've read in ASI threads.  Whether this happens the first winter after a BOE or not until the 20th one, is far beyond me.  This was seen in the Arctic during the early Eocene (~50 ma = 50 million years ago) when crocodiles basked on Arctic shores.  (The Earth was also ~8 degrees warmer then.  I don't think there is strong evidence of this happening since then.  Lots has changed since then:  Panama strait closure amongst them)

Of course, even a little mixing would delay the onset of freezing some, and the more delay of freezing, the more potential for more mixing.
Title: Re: Ice-free Arctic
Post by: Tealight on March 25, 2018, 10:23:02 PM
Just to make sure that what i think is right. Because the term albedo is new for me. But it represents the capacity of an object  to reflect the sunlight, correct ? So a low albedo means the sunlight is not reflected, but used to melt the ice or to warm  the water. So that makes me think that all the red colour you see, reflects the bad condition of the ice, or the snow on top of it. Is that correct ?

Yes i use the standard red=hot, blue=cold heat-map. Or in this case low albedo=hot=red, high albedo=cold=blue.

Just to make sure that what i think is right. Because the term albedo is new for me. But it represents the capacity of an object  to reflect the sunlight, correct ? So a low albedo means the sunlight is not reflected, but used to melt the ice or to warm  the water. So that makes me think that all the red colour you see, reflects the bad condition of the ice, or the snow on top of it. Is that correct ?
When Tealight/Nico Sun calculates albedo-warming potential (very useful btw), he is dealing with the effect of open water albedo (compared to ice/snow-covered ice), multiplied by the insolation level on that date in that location. As far as I understand, he is not dealing with the state of the ice, the state of its snow cover, or the state of clear sky vs. cloudiness.

Well, I indirectly consider the state of sea ice. The NSIDC data (NASA Team algorithm) is very sensitive to melt ponds. During peak summer a fully ice covered grid cell might show as 60% sea ice concentration due to melt ponds. My AWP algorithm then treats the cell as 40% ocean. It wouldn't work as well with AMSR2 data.
Title: Re: Ice-free Arctic
Post by: Iceismylife on March 25, 2018, 11:24:32 PM
...
  Therefore, making the extraordinary claim of an ice-free Arctic in less than a decade, requires extraordinary evidence to go against the current trend.

...
The current trend is the four lowest maximum ice volume years are the last four years.

The current trend is ice free very soon.
Title: Re: Ice-free Arctic
Post by: Archimid on March 26, 2018, 12:17:30 AM
We could have possibly lost much of the summer ice during the Holocene climatic optimum and the Eemian. Still, it did not lead to runaway instabilization of the global climate.

Let me tell you my theories about that. First some context.

(https://pbs.twimg.com/media/DZEqRN_XkAINURn.jpg:large)

I agree 100% that the Arctic didn't have ice during the Eemian 135,000 years ago. There is plenty of evidence supporting that. It lasted for thousands of years, enough to develop a flora and fauna comparable to today's tropics. It was great, except that the human population of the time was about 20,000 individuals.

The Eemian started when Milankovitch cycles aligned and kicked started the CO2 cycle. The temperatures climbed for 10,000 years, melting the Arctic past the Holocene average, and remaining much warmer for 5,000 years. When Milankovitch cycles subsided things cooled down until eventually the Arctic returned. After the return of the Arctic and with it winter, glaciation commenced for the next 100,000 years.

The Holocene started in the same way the Eemian started. The sun kicked start the CO2 cycle and the world warmed for 8,000 years but then the Younger Dryas happened. Regardless of why it happened, global temperatures were held back for a thousand years, lowering CO2 and wasting time in sync with milankovitch cycles.

By the time maximum CO2+insolation was reached it was too late. The Arctic sea ice cap was saved. The ice would teeter in and out of existence during the Holocene Thermal Maximum but the gigantic ice sheets of the Northern Hemisphere protected it.

 4,000 years later the time the maximum isolation+CO2 is over. Humans are left with a warm planet that's not as warm as the Eemian and but much warmer than the glacial times. Just perfect to grow food using agriculture over most of the planet. Over the next 5000 years temperatures remain relatively constant even when milankovitch cycles slowly decay overtime. CO2 product of human burning of trees and agriculture keeps the planet sufficiently warm.

Then 200 years ago humans discovered fossil fuels. Ancient Solar energy stored in dead ancient forests. In 200 years we took CO2 from 280 ppm to 410ppm. During the Eemian it only reached 300ppm. Now temperatures are responding to CO2 and the CO2 cycle has been kickstarted again. Soon the Arctic will be gone and it won't be back until CO2 is reduced.


Title: Re: Ice-free Arctic
Post by: Daniel B. on March 26, 2018, 12:45:20 AM
...
  Therefore, making the extraordinary claim of an ice-free Arctic in less than a decade, requires extraordinary evidence to go against the current trend.

...
The current trend is the four lowest maximum ice volume years are the last four years.

The current trend is ice free very soon.

We are referring to ice-free at minimum, not maximum.  It will be a very long time (if ever) before the Arctic will be ice-free during the winter.
Title: Re: Ice-free Arctic
Post by: Archimid on March 26, 2018, 02:42:17 AM
 If we assume a BOE will happen soon and it doesn't, we are at least better prepared for when it does.

 If we assume a BOE won't happen soon and it does civilization as we know it is finished.

Title: Re: Ice-free Arctic
Post by: oren on March 26, 2018, 05:31:21 AM
Here is some data to help ground the discussion. As ice grows more dispersed over time, I think area can often give better clues than extent.
A. It's a long gradual process, and human civilization will not end tomorrow one way or the other. (But wait 50 years and we're probably doomed.  But that's a different thread).
B. I don't think there's a slowdown. Cherry-pick the June 1st graph for difficulty with the slowdown notion. Remember June is peak insolation month, and area is the parameter affecting albedo.
C. As the trend is down, AND volatility to the downside is increasing, as stated up-thread I would be highly surprised if a BOE (<1M km2 extent (or area?) at min) doesn't show up by 2030.

Edit: the chart was wrong due to the pole hole issue, and was removed. Posted later.
Title: Re: Ice-free Arctic
Post by: crandles on March 26, 2018, 01:11:26 PM
Cherry-pick the June 1st graph for difficulty with the slowdown notion. Remember June is peak insolation month, and area is the parameter affecting albedo.

Area at June 1 well constrained by land hence it is practically a straight horizontal trend?

Practically a straight horizontal trend doesn't seem like a good argument for a near term BOE.
Title: Re: Ice-free Arctic
Post by: oren on March 26, 2018, 01:25:15 PM
Cherry-pick the June 1st graph for difficulty with the slowdown notion. Remember June is peak insolation month, and area is the parameter affecting albedo.

Area at June 1 well constrained by land hence it is practically a straight horizontal trend?

Practically a straight horizontal trend doesn't seem like a good argument for a near term BOE.

True, but I mentioned it, with its significant record low of 2016, as an argument against a gompertz-style slowdown with a 2007 inflection point.
If 2016 with its terrible winter had a 2012-like summer weather, we might already have been halfway to a BOE right then.
Title: Re: Ice-free Arctic
Post by: crandles on March 26, 2018, 02:38:52 PM
Hmm probably got part of my last answer wrong.

Would prefer a straight line to fit below.

CT area data stopped in early 2016, so haven't got last two years in this which would probably change direction of curve.

Edit:
Wondering if this means there are step changes in NSIDC area data as the pole hole has reduced in size which you haven't taken into account. That issue existed with their monthly data.

Edit 2: I see you recalled this before me.
Title: Re: Ice-free Arctic
Post by: oren on March 26, 2018, 02:46:35 PM
Hmm probably got part of my last answer wrong.

Would prefer a straight line to fit below.

CT area data stopped in early 2016, so haven't got last two years in this which would probably change direction of curve.
Looking at your chart, it seems I got my data wrong. As I couldn't find an immediate NSIDC area graph, I took ths NSIDC regional spreadsheet and summed the area of all the regions. Now I recall the pole hole issue, which changed size at some point. I will check the data later tonight.
Title: Re: Ice-free Arctic
Post by: crandles on March 26, 2018, 03:22:01 PM
If 2016 with its terrible winter had a 2012-like summer weather, we might already have been halfway to a BOE right then.

I tend to think this about 2017 rather than 2016 because of its low maximum volume. A record equalling melt volume would have taken us down to 1336km^3 for Sept so that would be getting fairly close to virtually ice free.

This 'if' didn't happen once (surprisingly getting a below average melt volume when the trend appears to be upward). Hard to get a feel of whether likely to happen soon from just one instance. However, this does make me nervous that my arguing for slowing down trend may be wrong.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 26, 2018, 06:47:55 PM
Here is some data to help ground the discussion. As ice grows more dispersed over time, I think area can often give better clues that extent.
A. It's a long gradual process, and human civilization will not end tomorrow one way or the other. (But wait 50 years and we're probably doomed.  But that's a different thread).
B. I don't think there's a slowdown. Cherry-pick the June 1st graph for difficulty with the slowdown notion. Remember June is peak insolation month, and area is the parameter affecting albedo.
C. As the trend is down, AND volatility to the downside is increasing, as stated up-thread I would be highly surprised if a BOE (<1M km2 extent (or area?) at min) doesn't show up by 2030.

I think area would give better clues than extent, if we have better area measurements.  Area and extent correlate quite well during the colder months, when a significant fraction of the Arctic is ice covered (area always being smaller).  However, in the summer months, melt ponds form on the ice, fooling the satellite sensors into thinking it is open water.  Extent measurements will not be affected as much, as these ponds will not cover enough ice to rate them as open water. 

This graph shows how the correlation between area and extent breaks down in the summer:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fneven1.typepad.com%2F.a%2F6a0133f03a1e37970b013485eb2658970c-pi&hash=5a597d122dc1f1935b6f5ef51f3d8c6c)
Title: Re: Ice-free Arctic
Post by: oren on March 26, 2018, 08:53:31 PM
Here is the real chart from NSIDC area, including the pole hole counted as full concentration. Luckily, it is now of negligible size.
Anyway, the June 1st curve still defies a statistical slowdown, in my view.
Title: Re: Ice-free Arctic
Post by: oren on March 26, 2018, 09:01:08 PM
I think area would give better clues than extent, if we have better area measurements.  Area and extent correlate quite well during the colder months, when a significant fraction of the Arctic is ice covered (area always being smaller).  However, in the summer months, melt ponds form on the ice, fooling the satellite sensors into thinking it is open water.  Extent measurements will not be affected as much, as these ponds will not cover enough ice to rate them as open water. 

This graph shows how the correlation between area and extent breaks down in the summer:
I believe August doesn't have lots of melt ponds, as a large fraction of them usually drain through the ice by then. I see this interesting chart as showing something different (in combination with melt pond and rain "noise") - the growing dispersion of the ice during late summer, as the pack becomes weaker and more mobile. One of those "ice internals" showing that the Arctic is not in a stable hiatus but on a downward trend.
In any case, it would be interesting to view this chart all the way to the present.
Title: Re: Ice-free Arctic
Post by: Tor Bejnar on March 26, 2018, 09:40:43 PM
Quote
... view this chart all the way to the present.
I want to see that chart "into the future".   ;D 8) :o :P ::)
Wait; that's speculation;  wrong thread.
Title: Re: Ice-free Arctic
Post by: Iceismylife on March 27, 2018, 01:14:32 AM
...

We are referring to ice-free at minimum, not maximum.  It will be a very long time (if ever) before the Arctic will be ice-free during the winter.
First.  How long can we sustain the trend of the last four years being the lowest extent at maximum before the minimum reaches zero?  The minimum is a fraction and a function of the maximum.  The relation is complicated and not linear. But if you keep dropping maximum then the minimum should follow.
Second.  There has been some math done on this forum that shows that if you go ice free you stay ice free in the arctic ocean in the winter.  But you can see it in these two photos. The first one is in infrared the second is in visible light.
https://go.nasa.gov/2GeYlR6
https://go.nasa.gov/2GfvfB0

The cloud tops are cooler (darker) than the ice.  Open water will have less heat loss do to radiation than ice covered water.  It will have a lot more heat loss do to evaporation.  But with mixing from waves and other sources there is plenty of heat there to keep the water open after it goes ice free.

(And with those clouds going from one side of the arctic ocean to the other when they hit a rise on the other side they will drop a fraction of their water as snow. But that is for another thread)
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 27, 2018, 02:03:41 AM
Considering that the minimum has not declined over the past four years, it is hard to say.  The minimum is not a direct function of the maximum.  If it were, the past four years would be the lowest, and not 2012 and 2007.  The ultra low minimum in 2012, was surrounded by relatively high maxima both prior to and following the summer minimum (high for the past fifteen years).  While intuitively, it would makes sense that the minimum would follow a falling maximum, in reality, that is not occurring.

I disagree that an ice-free Arctic in summer will lead to an ice-free winter.  Open water will lose more heat, and it will refreeze.  Additionally, the ice adjacent to the islands will spur further ice growth seaward.  The cloud albedo is only part of the radiation equation; the clouds themselves will absorb solar radiation and retaliate heat skyward, in the same manner that they absorb terrestrial heat and reradiate earthward.
Title: Re: Ice-free Arctic
Post by: Iceismylife on March 27, 2018, 02:32:41 AM
...

I disagree that an ice-free Arctic in summer will lead to an ice-free winter.  Open water will lose more heat,
I agree with you up to here.
and it will refreeze.
I disagree with you here.  Open water is subject to physical processes that ice covered water isn't.  It is subject to mixing by wave action.  The arctic ocean has a low salinity top layer that limits heat available to reject to the atmosphere.  Mix that layer in with the warmer lower water and there is plenty of heat to keep it from refreezing.
  Additionally, the ice adjacent to the islands will spur further ice growth seaward.
I agree with you.  Butt and this is a big one.  Generate enough bottom water and you reverse the surface flow past Greenland. That would pull the heat from the equator into the arctic ocean.
The cloud albedo is only part of the radiation equation; the clouds themselves will absorb solar radiation and retaliate heat skyward, in the same manner that they absorb terrestrial heat and reradiate earthward.
The gulf stream will melt all the ice that forms next to the islands.  Once ice free it will stay ice free. IMO.
Title: Re: Ice-free Arctic
Post by: be cause on March 27, 2018, 02:53:46 AM
Ice -free ? .. I give it 6 months (again :) ).
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 27, 2018, 03:11:38 AM
The gulf stream will melt all the ice that forms next to the islands.  Once ice free it will stay ice free. IMO.

Currently, the glue stream does not make its way through the Canadian archipelago.  After passing Iceland, it flows into the Arctic on the Russian side.  By the time it reached the islands, it has circumvented the Arctic and cooled substantially.
Title: Re: Ice-free Arctic
Post by: oren on March 27, 2018, 04:08:38 AM
The arctic ocean will become seasonally ice-free, same as the peripheral seas today, long before it becomes ice-free in winter. Very long. Can't say much more than that, as too much is unknown.
Title: Re: Ice-free Arctic
Post by: crandles on March 27, 2018, 11:16:51 AM

and it will refreeze.
I disagree with you here.  Open water is subject to physical processes that ice covered water isn't.  It is subject to mixing by wave action.  The arctic ocean has a low salinity top layer that limits heat available to reject to the atmosphere.  Mix that layer in with the warmer lower water and there is plenty of heat to keep it from refreezing.

I am unsurprisingly with Daniel B.

If the temp was likely to stay at -10C or higher throughout winter and add in lots of strong storms to stir up the water and you might get severely reduced ice formation. (There is quite a bit of shallow water that loses any heat throughout the water column so you can't stir up heat from 50m down because it is shallower than 50m.)

From 1970 to 2017 temperatures in winter have increased from somewhere about -28C to about -23C so at that rate it is about 100 years before we reach -10C. (rough figures by eye from http://ocean.dmi.dk/arctic/meant80n.uk.php )

In addition, there is bound to be some periods and areas between storms where it is still wavy but not enough to stir heat up from 50m down. If the temp is below -10C plenty of tiny ice platelets (frazil ice) form and enough of these will damp down the waves allowing further stages of ice formation to be reached.

Even if your mechanism did work one year, so much heat would be lost from below 50m deep, the next winter there would be less heat at this depth where it is needed for this to occur that it is hard to see it being sustainable for more than a couple of winters and when it fails there would be less upward heat flux such that more ice than normal would form.
Title: Re: Ice-free Arctic
Post by: Gray-Wolf on March 27, 2018, 12:55:57 PM
I think it was last year that one of us approached NSIDC over the 15% cutoff and the issues it places on the measure of a highly fragmented 'inner pack'?

The reply was along the line of 'we know there is an issue.The measure evolved to better capture the peripheral ice and was not set up to measure internal ice'.

Basically , in the past, the ice beyond 80N would have been contiguous ice. Now it can be 16% ice covered yet be measured as it used to as 'contiguous ice'. This is a nonsense!

The increasingly open pack in the high Arctic ( since 2012) means the final ice figures are increasingly incorrect as we move down to the 15% cut off.

This notion of " when the ice goes it will go pretty fast" is even more true if we see areas 'blink out' that have been reducing down to the 15% cut off at seasons end for years.
Title: Re: Ice-free Arctic
Post by: crandles on March 27, 2018, 02:54:32 PM
The trend in volume melt has been upward. Once we reach completely ice free in summer every year, the volume melt has to decline as maximum volume declines.

The immediate natural assumption is that as max volume goes down the thickness goes down and this changes to low albedo faster so more volume melts, thus the maximum volume melt occurs as we reach seasonally completely ice free.

However, there is the possibility that a max volume melt was reached in 2012. The FYI that melts out every year is now getting thinner so there is less volume melt in these areas as time goes on. This is to some extent compensated by earlier melt further into the pack. However the area that is further into the pack is getting smaller. As this gets smaller, it might be possible that the extra melt volume in these area further into the pack is less and less able to compensate for the less melt of the FYI that melts out every year.

The trend in melt volume looks upward so there is little if any trend data to support the idea that volume melt max has passed. However there were some experiments with models reducing the ice thickness to 1m. While a lot melted, there was still some ice left at the minimum. This potentially supports the idea that the max melt volume might well be before we reach seasonally ice free.

Reactions to this? (probably not hard to guess)
Title: Re: Ice-free Arctic
Post by: oren on March 27, 2018, 03:05:43 PM
Reactions to this? (probably not hard to guess)
Actually makes a lot of sense. Lack of significant MYI and low winter maxima mean less ice available for melting. Indeed the most probable conclusion is that max volume melt will be in the first year of a BOE (if it wasn't in 2012).
Title: Re: Ice-free Arctic
Post by: Archimid on March 27, 2018, 04:08:45 PM
Considering that the minimum has not declined over the past four years, it is hard to say.  The minimum is not a direct function of the maximum.  If it were, the past four years would be the lowest, and not 2012 and 2007.

If initial conditions include Arctic sea ice, then minimum volume and maximum volume are both mostly functions of the tilt of the Earth and its orbit around the Sun.  Ice volume is a direct function of available heat in the system and most of the heat in the system is ultimately provided by the sun. The earth's climate generates the noise. That noise provides us with ceilings and floors for the total heat available to melt ice or freeze water.

Losses and gains of annual volume are a direct representation of all the heat available to the ice after the noise of the climate system.  The low and high bounds for the heat available to Arctic are given by the Minimum and Maximum of the gains and losses. Everything in between is the climate. Here is the breakdown of the noise:

 The first attachment has a chart for volume losses and gains from 1980-2006. Here are the stats:

                 Gain         Loss
Average   16.14   16.43
Median   16.3           16.33
Maximum   17.62   18.31
Minimum   14.71   13.93
SD           0.71           1.01


 The average volume loss was 16.43 and the average gain was 16.14. Gains and losses have similar variation, both relatively low, with the gains having the lowest noise.

Then the minimum collapsed in 2007. See the second attachment for a chart with volume loses and gains from 2007-2017. Here are the stats:

                Gain         Loss
Average   17.69   18.09
Median   17.73   18.24
Maximum   19.66   19.69
Minimum   14.87   16.25
SD       1.72   1.27

After 2007 both gains and losses increased significantly and the losses increased more than the gains.  The lower bound for the gains remained about the same and the upper bound of gains increased significantly. The lower bound for the losses increased significantly,  matching the old average losses.

Variation increased slightly for the losses, but look at the variation of the gains. The variation of the gains more than doubled.

 
Quote
The ultra low minimum in 2012, was surrounded by relatively high maxima both prior to and following the summer minimum (high for the past fifteen years).  While intuitively, it would makes sense that the minimum would follow a falling maximum, in reality, that is not occurring.

2012 is preceded by a near record low maximum, 2007 and 2016 are preceded by record low maximums. At current volumes a mere average loss puts the Arctic at record low levels. Maximum losses crash the minimum to never before seen levels.  See the third attachment.
Title: Re: Ice-free Arctic
Post by: Archimid on March 27, 2018, 04:13:47 PM
The arctic ocean will become seasonally ice-free, same as the peripheral seas today, long before it becomes ice-free in winter. Very long. Can't say much more than that, as too much is unknown.

I think that ice volume will follow the path suggested by the following visualization by Jim Pettit

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fiwantsomeproof.com%2Fextimg%2Fsiv_annual_polar_graph.png&hash=d6c593514f63b413f80efe8f8d00fbce)

Once volume reaches 0 the loops become very small for a few more roundabouts and then for all intent and purposes the ice will be gone. It will remain that way until we remove all that extra CO2 and methane from the atmosphere.
Title: Re: Ice-free Arctic
Post by: Archimid on March 27, 2018, 04:30:19 PM
If the temp was likely to stay at -10C or higher throughout winter and add in lots of strong storms to stir up the water and you might get severely reduced ice formation. (There is quite a bit of shallow water that loses any heat throughout the water column so you can't stir up heat from 50m down because it is shallower than 50m.)

That is the expected outcome. After the last bout of healthy growth in 2013-2014 much of the endogenous cold of the Arctic was used up. Since then growth has been anemic and matched by extremely high temperatures.

Quote
From 1970 to 2017 temperatures in winter have increased from somewhere about -28C to about -23C so at that rate it is about 100 years before we reach -10C. (rough figures by eye from http://ocean.dmi.dk/arctic/meant80n.uk.php )

That is extremely misleading. Most of that increase happened just in the last three years. for the rest of the datase the DMI temperatures are very close to the average. So when yo project into the future, you have 36 data points with almost normal temperatures and the last 3 with all the heat. Can you please make a sanity check  to that statement? 

Quote
In addition, there is bound to be some periods and areas between storms where it is still wavy but not enough to stir heat up from 50m down. If the temp is below -10C plenty of tiny ice platelets (frazil ice) form and enough of these will damp down the waves allowing further stages of ice formation to be reached.

Why this doesn't happen now? All growth of ice that I have seen comes from the ice edge. not from random cold spots above the ocean.

Quote
Even if your mechanism did work one year, so much heat would be lost from below 50m deep, the next winter there would be less heat at this depth where it is needed for this to occur that it is hard to see it being sustainable for more than a couple of winters and when it fails there would be less upward heat flux such that more ice than normal would form.

You speak as if the heat loss by the ocean magically disappears. That heat lost by the oceans goes into resulting in warmer atmosphere , which results in less FDD's which results in less ice.

Look at the Chukchi right now. Where was that extra growth that you claim it will happen? We saw the exact opposite. Anemic ice growth and high atmospheric temperatures. 
Title: Re: Ice-free Arctic
Post by: Archimid on March 27, 2018, 04:51:15 PM
The trend in volume melt has been upward. Once we reach completely ice free in summer every year, the volume melt has to decline as maximum volume declines.

Completely wrong. If we take the whole data set the rate of volume melt is increasing. If we take the trend since 2007 until the end then the trend is slightly decreasing but the lowest lows are equal to the average of the losses in the past. and the average loses are higher than the average of the past. Melting is outpacing freezing.

Quote
However, there is the possibility that a max volume melt was reached in 2012. The FYI that melts out every year is now getting thinner so there is less volume melt in these areas as time goes on.
 

Yes but the available heat in the system is the same. If it doesn't go to melt ice it must go somewhere else. Right now it looks like a good chunk of it is going into the atmosphere above the Arctic

Quote
This is to some extent compensated by earlier melt further into the pack. However the area that is further into the pack is getting smaller. As this gets smaller, it might be possible that the extra melt volume in these area further into the pack is less and less able to compensate for the less melt of the FYI that melts out every year.

Earlier melt means more heat over less ice, meaning there is more heat available to melt the center of the pack.

Quote
The trend in melt volume looks upward so there is little if any trend data to support the idea that volume melt max has passed.


Even if a peak in melt(losses) was reached, Max volume is still dropping. Right now an average volume loss for the last 11 years puts us at near record low volume while a repeat of a Max volume loss puts us at record low levels. If such event happen, will the gains recover to 2012 levels? The warming experienced in the Arctic over the last three years indicate no.

Quote
However there were some experiments with models reducing the ice thickness to 1m. While a lot melted, there was still some ice left at the minimum. This potentially supports the idea that the max melt volume might well be before we reach seasonally ice free.

It doesn't matter.
Title: Re: Ice-free Arctic
Post by: Archimid on March 27, 2018, 04:54:34 PM
Reactions to this? (probably not hard to guess)
Actually makes a lot of sense. Lack of significant MYI and low winter maxima mean less ice available for melting. Indeed the most probable conclusion is that max volume melt will be in the first year of a BOE (if it wasn't in 2012).

Yes but if there is less ice to melt, where all the heat that was supposed to melt that ice goes?
Title: Re: Ice-free Arctic
Post by: oren on March 27, 2018, 05:02:48 PM
Reactions to this? (probably not hard to guess)
Actually makes a lot of sense. Lack of significant MYI and low winter maxima mean less ice available for melting. Indeed the most probable conclusion is that max volume melt will be in the first year of a BOE (if it wasn't in 2012).

Yes but if there is less ice to melt, where all the heat that was supposed to melt that ice goes?
Eventually, when a BOE is reached and no more summer ice is available to melt, SSTs will rise.
But regardless of all this, even when the arctic is a real ocean with no grain of ice in sight, you will still get winter ice growth at some point for a long time to come. Currently ice typically grows from the vicinity of more ice (not always!) because that vicinity has fresher surface water, colder SSTs, less waves, and colder air temps. But during the long polar night, even with waves and warm autumn SSTs and whatever, a calm cold day will come at some point with -30 or -25 or -20 degC, and the surface will freeze into ice. That is just plain weather.
Title: Re: Ice-free Arctic
Post by: crandles on March 27, 2018, 05:13:21 PM

Quote
From 1970 to 2017 temperatures in winter have increased from somewhere about -28C to about -23C so at that rate it is about 100 years before we reach -10C. (rough figures by eye from http://ocean.dmi.dk/arctic/meant80n.uk.php )

That is extremely misleading. Most of that increase happened just in the last three years. for the rest of the datase the DMI temperatures are very close to the average. So when yo project into the future, you have 36 data points with almost normal temperatures and the last 3 with all the heat. Can you please make a sanity check  to that statement? 

If it was just the last three years I would be writing that off to natural variation. It takes place over much longer than that. However you do have a point, I just said 1970 as well known date that global temperatures started to rise after 1940-1970 aerosol induced hiatus. 2008 and 2004 were as low as the early years. Perhaps 1985-1989 might be the lowest 5 years average but then 1990 was surprisingly warm. So they are a bit all over the place. It would be nice to see lines for decadal averages rather than one long period average. Not sure if someone found the data to do that at some point. My impression is the cold years generally get less frequent over time.

Perhaps I should only be attributing that 5C change to last 25 years rather than 37 and maybe there is some acceleration, but it seems hard to tell. Maybe someone has a better data set?

Re "After the last bout of healthy growth in 2013-2014 much of the endogenous cold of the Arctic was used up."

Not sure what you are saying on a few counts:
1) Of the last 10 years, only the last years volume freeze was below average. 2013 and 2014 were high but how can you attribute this to anything other than random variation?
2) What do you mean by endogenous cold?
3) "used up"? Huh? There is no sunlight every winter. The temperature rises come from a) heat stored in the ocean built up over summer, b transported by winds & currents, and c more GHG in atmosphere reducing rate of emission from atmosphere to space. I don't see any reason to think any of these will do anything other than slowly increase over long periods of time.

>"Why this doesn't happen now? All growth of ice that I have seen comes from the ice edge. not from random cold spots above the ocean."

Why would you get a cold spot above the ocean, unless there was wind coming from a direction where there was ice or snow. The further it gets from that ice or snow the more it has warmed up and is less able to cool the water sufficiently. We don't really have resolution to see small amounts of ice forming and match it to openings in clouds which allow faster radiation loss to space.

>"You speak as if the heat loss by the ocean magically disappears"
A small amount goes direct from ocean to space. Most is from ocean to atmosphere and then atmosphere to space. No idea why you are thinking I am thinking something other than that.
Title: Re: Ice-free Arctic
Post by: Archimid on March 27, 2018, 05:16:36 PM
Oren I 100 percent agree with you. Ice will form in winter no matter what. The Arctic night is very long. And regardless how warm it gets there is Greenland there providing low albedo and fresh water.

However, the amount of ice will be large enough to make any difference when the sun comes back.

After the ice is gone for the first time, I bet growth starts north of Greenland and grows out from there.  Because the bathymetry of the Arctic and the cold arctic night it is likely that ice grows very fast over the arctic basin but then slows down due to very high Arctic temperatures.

At the end of the freezing season there will a very small amount of ice in the Arctic, literally all of it thin first year ice. When the Sun comes back and the melting season begins that ice will be gone record fast and all the heat that is normally in the system that didn't get to melt ice stays in the Arctic, warming it and delaying the formation of ice the next winter.

While the Greenland ice sheet is there, there will be at least some form of ice in the Arctic. Hopefully, that's a long time.
Title: Re: Ice-free Arctic
Post by: crandles on March 27, 2018, 05:22:24 PM
Reactions to this? (probably not hard to guess)
Actually makes a lot of sense. Lack of significant MYI and low winter maxima mean less ice available for melting. Indeed the most probable conclusion is that max volume melt will be in the first year of a BOE (if it wasn't in 2012).

Yes but if there is less ice to melt, where all the heat that was supposed to melt that ice goes?

Yes it warms ocean during melt season. Come winter, it gets vented to atmosphere warming atmosphere. Then if there is more heat in the atmosphere there is a greater temperature difference to space's 4K temp so there is a slightly higher rate of heat loss to space. With this higher rate of heat loss there is plenty of time in fall & winter to radiate it to space and then start forming ice. OK forming ice gets delayed slightly and the ice ends up slightly thinner as a result but no one is denying this.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 27, 2018, 05:46:05 PM
Oren I 100 percent agree with you. Ice will form in winter no matter what. The Arctic night is very long. And regardless how warm it gets there is Greenland there providing low albedo and fresh water.

However, the amount of ice will be large enough to make any difference when the sun comes back.

After the ice is gone for the first time, I bet growth starts north of Greenland and grows out from there.  Because the bathymetry of the Arctic and the cold arctic night it is likely that ice grows very fast over the arctic basin but then slows down due to very high Arctic temperatures.

At the end of the freezing season there will a very small amount of ice in the Arctic, literally all of it thin first year ice. When the Sun comes back and the melting season begins that ice will be gone record fast and all the heat that is normally in the system that didn't get to melt ice stays in the Arctic, warming it and delaying the formation of ice the next winter.

While the Greenland ice sheet is there, there will be at least some form of ice in the Arctic. Hopefully, that's a long time.

Good.  Something else upon which we agree.  The ice north of Greenland and around the Canadians islands will remain as long as the glacial ice remains on those landforms (hopefully a very long time).  Hence the term ice-free refers to less than 1 million sq. km., and not zero ice, as scientists readily admit that this ice will not melt easily.  The ice is likely to spread rapidly each winter, due to the absence of sunlight, and is likely to melt rapidly, due to its fragility.  This could lead to large inter-annual variability, as small changes in incoming solar radiation, cloudiness, ocean temperature and currents, etc. could have large implications. 

For these reasons, neither ice volume nor extent are likely to ever reach zero.  In reality, they will probably fall to some value, dependent on the adjacent land ice.  We should not get overly concerned about the 1 million number, as it is somewhat arbitrary.  The actual value may be several hundred thousand higher or lower, but represents the ice grounded to the adjacent land glaciers plus some surrounding floating ice.
Title: Re: Ice-free Arctic
Post by: Archimid on March 27, 2018, 06:34:42 PM
1) Of the last 10 years, only the last years volume freeze was below average. 2013 and 2014 were high but how can you attribute this to anything other than random variation?

I attribute that growth to the ice being very thin and the atmosphere almost as cold as average.

Quote
2) What do you mean by endogenous cold?

For example the temperature of the water under the Chukchi sea or the Beaufort. For most of the record those areas were almost completely covered in ice  year round keeping them nice and cold. I imagine (can't find data) that since the 2007 cover changes the areas with significant cover changes are becoming warmer. That effect was barely noticeable from 2007-2014, but it accumulates By 2015 those cold spots lost their "endogenous cold" and no longer help with the freezing. The same happens with hot air intrusions. Once the endogenous cold of the Arctic kept the Arctic dry and the heat from the hemisphere away. But as the arctic warms, warmth is allowed in, warming it more.

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3) "used up"? Huh? There is no sunlight every winter. The temperature rises come from a) heat stored in the ocean built up over summer, b transported by winds & currents, and c more GHG in atmosphere reducing rate of emission from atmosphere to space. I don't see any reason to think any of these will do anything other than slowly increase over long periods of time.

a) heat stored in the ocean built up over summer:

Like the Chukchi this year. It was hot and releasing heat to the atmosphere until very late in the freezing season. Eventually it covered in ice but I bet there is still extra heat underneath the ice. From the looks of thing this year the pattern will be reinforced.

b)  transported by winds & currents

And that has increased over the years. The less ice, the more humid and the more warm air intrusions.

 c) more GHG in atmosphere reducing rate of emission from atmosphere to space

I think that can best be appreciated in the baseline of winter temperatures in DMI N80. Even in winter temperatures seem to have a new baseline. that new baseline is induced by higher arctic water vapor and clouds who are bound to increase even more as more ocean remains open for longer. Hot air intrusions also add to the new baseline.


>"Why this doesn't happen now? All growth of ice that I have seen comes from the ice edge. not from random cold spots above the ocean."

Why would you get a cold spot above the ocean, unless there was wind coming from a direction where there was ice or snow. The further it gets from that ice or snow the more it has warmed up and is less able to cool the water sufficiently. We don't really have resolution to see small amounts of ice forming and match it to openings in clouds which allow faster radiation loss to space.

>"You speak as if the heat loss by the ocean magically disappears"
A small amount goes direct from ocean to space. Most is from ocean to atmosphere and then atmosphere to space. No idea why you are thinking I am thinking something other than that.
[/quote]

Because if you are citing high ice growth rates because the oceans will vent heat. However high growth rates are also dependent on atmospheric temperatures. If the ocean vents heat to the atmosphere, the atmosphere will warm precluding ice formation. Also much of that heat will be in the form of water vapor, which serves to keep the warmth in during the winter night.

I guess that what I'm trying to say is that the fast growth you are counting on won't happen because it will simply be too warm for rapid ice growth.
Title: Re: Ice-free Arctic
Post by: Archimid on March 27, 2018, 06:46:36 PM
Yes it warms ocean during melt season.

It warms the ocean and the atmosphere.

Quote
Come winter, it gets vented to atmosphere warming atmosphere.

and that venting gets slowdown by the already warm and humid atmosphere, prolonging the time the atmosphere is warm.

Quote
Then if there is more heat in the atmosphere there is a greater temperature difference to space's 4K temp so there is a slightly higher rate of heat loss to space.


only if there are few clouds. High humidity might keep much of that heat in.

Quote
With this higher rate of heat loss there is plenty of time in fall & winter to radiate it to space and then start forming ice. OK forming ice gets delayed slightly and the ice ends up slightly thinner as a result but no one is denying this.

And that's the whole point. You start the freezing season late, from 0 and with a much warmer atmosphere. By the time the sun comes back it will eat all the ice very quick, allowing even more sun in the following year. Warming the arctic even more and further delaying the onset of freezing.
Title: Re: Ice-free Arctic
Post by: Archimid on March 27, 2018, 07:23:58 PM
Hence the term ice-free refers to less than 1 million sq. km., and not zero ice, as scientists readily admit that this ice will not melt easily.

I don't think that assumption is correct. Bottom melt is real, so the whole Arctic basin is vulnerable to disappear. It hasn't dissapeared yet because the thickest ice is there and the heat of the whole melting season is wasted melting the periphery. As the periphery weakens, the heat keeps encroaching the basin.

I believe that when we get a large loss year the CAB will poof out of existence very quickly. Thi sis suggested by the fact that volume hits 0 much earlier than extent, suggesting that the last bit of extent will poof out.

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  The ice is likely to spread rapidly each winter, due to the absence of sunlight, and is likely to melt rapidly, due to its fragility.
 

The ice is likely to spread rapidly after a delay that could last months. Even when it will be extremely fast at first, even fast enough to pull a reverse poof, because the hot Arctic temperature ice growth will eventually slow to a crawl.


Quote
This could lead to large inter-annual variability, as small changes in incoming solar radiation, cloudiness, ocean temperature and currents, etc. could have large implications. 

We already have increased annual variability. after the ice s gone the variability will decrease in terms of there being a lot less ice made and a lot less ice melted.

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For these reasons, neither ice volume nor extent are likely to ever reach zero.  In reality, they will probably fall to some value, dependent on the adjacent land ice.  We should not get overly concerned about the 1 million number, as it is somewhat arbitrary.  The actual value may be several hundred thousand higher or lower, but represents the ice grounded to the adjacent land glaciers plus some surrounding floating ice.

A few rounds after the first BOE there will be literally 0 ice in the Arctic and temperatures of 20C maybe even 30C. However the winter night will definitely keep dropping below 0, most likely below -10. Some trivial ice will form every year.
Title: Re: Ice-free Arctic
Post by: Shared Humanity on March 27, 2018, 07:44:10 PM
The arctic ocean will become seasonally ice-free, same as the peripheral seas today, long before it becomes ice-free in winter. Very long. Can't say much more than that, as too much is unknown.

I agree. If we use the same standard for ice free as during melt season (1 million sq km) then an ice free winter is way out into the future. This is not to say that the winter ice, at max, will look anything like 30 years ago or even today but the ocean in the polar night will freeze.
Title: Re: Ice-free Arctic
Post by: Shared Humanity on March 27, 2018, 07:47:30 PM
I think it was last year that one of us approached NSIDC over the 15% cutoff and the issues it places on the measure of a highly fragmented 'inner pack'?

The reply was along the line of 'we know there is an issue.The measure evolved to better capture the peripheral ice and was not set up to measure internal ice'.

Basically , in the past, the ice beyond 80N would have been contiguous ice. Now it can be 16% ice covered yet be measured as it used to as 'contiguous ice'. This is a nonsense!

The increasingly open pack in the high Arctic ( since 2012) means the final ice figures are increasingly incorrect as we move down to the 15% cut off.

This notion of " when the ice goes it will go pretty fast" is even more true if we see areas 'blink out' that have been reducing down to the 15% cut off at seasons end for years.

And this is absolutely relevant to when the Arctic becomes seasonally ice free but not year round ice free.
Title: Re: Ice-free Arctic
Post by: Shared Humanity on March 27, 2018, 08:00:40 PM
After the ice is gone for the first time, I bet growth starts north of Greenland and grows out from there.  Because the bathymetry of the Arctic and the cold arctic night it is likely that ice grows very fast over the arctic basin but then slows down due to very high Arctic temperatures.

We are already seeing this in the Arctic. The drastically reduced ice, huddles near the CAA at minimum and, during the freeze season, grows rapidly outward. We also see ice form along land across Siberia even though it is essentially ice free at the end of the melt season. Meanwhile, we have vast expanses of open water soaking up heat during the melt season. This behavior will continue IMHO and the Arctic will continue to freeze during the polar night for a long time into the future. Yes, it will be mainly 1st year ice and we may, after the 1st BOE, see this occur often at minimum.
Title: Re: Ice-free Arctic
Post by: Shared Humanity on March 27, 2018, 08:04:36 PM

I think that ice volume will follow the path suggested by the following visualization by Jim Pettit

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fiwantsomeproof.com%2Fextimg%2Fsiv_annual_polar_graph.png&hash=d6c593514f63b413f80efe8f8d00fbce)

Once volume reaches 0 the loops become very small for a few more roundabouts and then for all intent and purposes the ice will be gone. It will remain that way until we remove all that extra CO2 and methane from the atmosphere.

I agree this chart could be a very good predictor of how the ice will behave once we hit zero ice but the chart does not support your conclusion. This chart shows that, as the ice has approached zero, we see an acceleration in the freeze and growth in volume. We also see an acceleration in the melting as 1st year ice which makes up more and more of the volume melts more rapidly. The resulting dimple in the chart will remain.

My guess is volume will reach at least 9000 cubic km after the 1st BOE.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 27, 2018, 08:09:32 PM
I disagree that there will be literally zero ice in the Arctic.  Even if all the ice were to disappear one summer, it would reform readily the following winter.  In every other body of water on this planet which experiences complete summer ice melt, the ice reforms in the winter.  Check out the Baltic and Okhotsk seas, which are significantly warmer than the Arctic. 

I disagree also with your temperature predictions.  According to the CRU temperature series, the average Arctic temperature has risen 2C over the past half century, all occurring during the winter months.  There has been no overall temperature change during the summer, during which temperature barely rise above 0:

(https://www.skepticalscience.com/print.php?r=286)

Title: Re: Ice-free Arctic
Post by: dnem on March 27, 2018, 08:27:20 PM
Daniel B., there are times when I question your sincerity.  You seem well informed enough to know why summer temps are pinned to 0 C.  In the absence of ice, they will no longer be pinned.
Title: Re: Ice-free Arctic
Post by: TerryM on March 27, 2018, 08:28:03 PM
Are there records that show increasing mist, fog, low clouds, in the high arctic? I recall Dr. Francis complaining of constant fog as she was steaming toward the pole very late in the season in (2012)?


Lots of water vapor has been assumed to account for the fossil alligators, primates, and rhinos found as far north as Ellesmere Island. It was a long time ago - but the sun wasn't shining there for months.


Lots of water vapor = lots of GHG keeping a cap over the Arctic.


Terry
Title: Re: Ice-free Arctic
Post by: El Cid on March 27, 2018, 08:48:45 PM
Daniel B., there are times when I question your sincerity.  You seem well informed enough to know why summer temps are pinned to 0 C.  In the absence of ice, they will no longer be pinned.

If the ice would completely melt out by June, then the water would have enough time to warm up and then air temps would rise significantly above zero.

However, during the "first phase" the ice will be gone only in August and by that time there will hardly be enough insolation to warm up the water, so even though we will lose the ice, water temps will probably not be much above zero in August and September, so ait temps will also be around zero. And then the polar night comes.

So, I agree with Daniel B. Even after we first lose the Arctic ice, summer temps will be pinned to zero for quite a long time.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 27, 2018, 08:49:44 PM
Daniel B., there are times when I question your sincerity.  You seem well informed enough to know why summer temps are pinned to 0 C.  In the absence of ice, they will no longer be pinned.

If you read my previous posts, you would see that I do not believe that there will be a complete absence of ice.  Hence, the temperatures will not rise significantly above 0. 
Title: Re: Ice-free Arctic
Post by: Telihod on March 27, 2018, 09:21:19 PM
If the ice would completely melt out by June, then the water would have enough time to warm up and then air temps would rise significantly above zero.

However, during the "first phase" the ice will be gone only in August and by that time there will hardly be enough insolation to warm up the water, so even though we will lose the ice, water temps will probably not be much above zero in August and September, so ait temps will also be around zero. And then the polar night comes.

So, I agree with Daniel B. Even after we first lose the Arctic ice, summer temps will be pinned to zero for quite a long time.

I remember hearing P. Wadhams in a youtube video (or maybe it was in his book, I'm not sure) that the surface temperature of the water was 17C somewhere over east siberian arctic shelf, and methane was coming out of the ocean, when he was on a ship. So  in those parts of the arctic where there is no ice in the vicinity, it can rise relatively high.
Title: Re: Ice-free Arctic
Post by: dnem on March 27, 2018, 09:24:10 PM
Daniel B., there are times when I question your sincerity.  You seem well informed enough to know why summer temps are pinned to 0 C.  In the absence of ice, they will no longer be pinned.

If you read my previous posts, you would see that I do not believe that there will be a complete absence of ice.  Hence, the temperatures will not rise significantly above 0.

That's fine, and I agree.  It seemed you were responding directly to this: "A few rounds after the first BOE there will be literally 0 ice in the Arctic and temperatures of 20C maybe even 30C."  When there is "literally 0 ice in the Arctic" temps will no longer be pinned.  Personally, I wouldn't be surprised to see some excursions above the 0 C line on the DMI 80 N plot during the summer over the next decade, even before all the ice is gone from the last refuges.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 27, 2018, 09:53:33 PM
Daniel B., there are times when I question your sincerity.  You seem well informed enough to know why summer temps are pinned to 0 C.  In the absence of ice, they will no longer be pinned.

If you read my previous posts, you would see that I do not believe that there will be a complete absence of ice.  Hence, the temperatures will not rise significantly above 0.

That's fine, and I agree.  It seemed you were responding directly to this: "A few rounds after the first BOE there will be literally 0 ice in the Arctic and temperatures of 20C maybe even 30C."  When there is "literally 0 ice in the Arctic" temps will no longer be pinned.  Personally, I wouldn't be surprised to see some excursions above the 0 C line on the DMI 80 N plot during the summer over the next decade, even before all the ice is gone from the last refuges.

Neither would I.  Large, sustained temperature rises, I cannot foresee.
Title: Re: Ice-free Arctic
Post by: Archimid on March 27, 2018, 11:01:07 PM
  Even if all the ice were to disappear one summer, it would reform readily the following winter.

After the first BOE, the ice will struggle to return.

Quote
I disagree also with your temperature predictions.  According to the CRU temperature series, the average Arctic temperature has risen 2C over the past half century.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fberkeleyearth.org%2Fwp-content%2Fuploads%2F2018%2F01%2FArctic2017-1024x582.png&hash=f9768a7c949267baa65db1a063926071)

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all occurring during the winter months

And it will remain that way until sufficient ice is gone.
Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 28, 2018, 12:00:14 AM
Quote
After the first BOE, the ice will struggle to return.

I've pasted links and excerpts of several peer-reviewed scientific papers that refute this argument.  Do you have any peer-reviewed studies that support it?

Why would the Arctic behave differently than other bodies of water that melt out and then refreeze seasonally?  It's much colder and in the dark much longer than they are.
Title: Re: Ice-free Arctic
Post by: be cause on March 28, 2018, 12:06:21 AM
My why's would include the Arctic being substantially different to those other bodies of water . b.c.
Title: Re: Ice-free Arctic
Post by: Tealight on March 28, 2018, 12:31:33 AM
The Arctic reaching 20-30C after a few blue ocean events, you guys lost it  ;D

The Arctic will still be a deep ocean and not a shallow lagoon. Currently all heat goes into the top 1-2m of the ocean melting the ice. Even heat from subsurface water ends up into the top 1-2m. After the ice is gone the bottom heat source becomes a heatsink and you have to heat several tenth of meters of water to get a significant temperature increase. The heat loss to space also increases by the power of four for every degree more. With your imagination the always ice-free waters around Iceland would already be a tropical paradise.
Title: Re: Ice-free Arctic
Post by: Shared Humanity on March 28, 2018, 01:56:09 AM
Thank you.
Title: Re: Ice-free Arctic
Post by: Archimid on March 28, 2018, 05:05:37 AM
I've pasted links and excerpts of several peer-reviewed scientific papers that refute this argument.  Do you have any peer-reviewed studies that support it?

This is going to be weird, but I will give you a reference and tell you why I think their model is wrong. I think similar arguments apply to any model predicting the ice gone by 2070 or growing back regardless of CO2 forcing. This paper is well written and I think someone quoted it before, maybe you.

Recovery mechanisms of Arctic summer sea ice

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2010GL045698

FTA:
Quote
All our experiments start from sea‐ice free conditions on 1st July. As expected, the Arctic Ocean remains ice‐free for several months, and significant sea‐ice cover does not develop before November. However, sea ice then grows very rapidly, since the growth rate for thin ice is much higher than for thick ice, which acts as a negative feedback on thickness during the growth season

Here is the illustration of the fast growth their model assumes:

(https://wol-prod-cdn.literatumonline.com/cms/attachment/0e0a697c-3721-4bac-85bc-2659d0b3fa74/grl27655-fig-0001.png)

This makes no sense. The first September have 0 ice. That means that growth started around November (according to the model) and then grew to such level that the extremely thin ice survived the next melting season with several million kilometers of ice to spare? Sorry but no. That is not realistic at all. I have never seen growth like that. Has anyone?
In fact the anemic growth of 2016, 2017 and 2018 prove that such fast growth is not necessarily true as the models assume.

 Let’s keep going

Quote
For SAT a large positive anomaly occurs between October and February after the initial perturbation, with a peak of almost 11 K in November (Figure 2). After February, there are no further SAT anomalies stronger than natural variability.


We are already halfway there with the temperature anomalies lasting well into March.  The extra heat the Arctic accumulated so far from albedo changes and wavy jet streams is nothing compared to a few months of full insolation without ice + atmospheric and ocean currents going crazy.

And the model expects super record extent growth with enough thickness to have ice left over by September? Considering the last three years, this is not plausible.

But wait, there is more:

(https://wol-prod-cdn.literatumonline.com/cms/attachment/37a757af-a0b4-46bd-8792-82fa8d25a30a/grl27655-fig-0003.png)

The paper calls this graph “Energy Budget of the Arctic Ocean Domain”. First let me say that it is a great graph, and the approach they took is elegant. I like the idea of the Arctic energy unit. However, the assumptions seem wrong after 2015. From September to March they have a net output of heat from the Arctic out to the planet. It seems to me that after 2015 that arrow was either reversed or significantly reduced.

On top of that, that arrow is not free. That energy goes back into the climate system and some of it ends up right back in the Arctic. After 2015 vapor plumes straight from the tropics are entering the Arctic.

And then there are clouds. A warm arctic is a humid arctic. And then there is methane pockets that will release quite a bit of methane when the Arctic warms. Anyway. The model fails a reality check.

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Why would the Arctic behave differently than other bodies of water that melt out and then refreeze seasonally?  It's much colder and in the dark much longer than they are.

 The Arctic Ocean will behave exactly like the other bodies of water. Ice will grow from more ice when the temperatures and salinity requirements are met. When there is no ice, the coasts make a good proxy for ice and from there it expands.

Ice also forms in the open water when it is very close to ice (hundreds of miles), but it has to be very cold for that. The very cold times in the arctic are already rare. This year we had like 15 days of average Arctic cold.
Title: Re: Ice-free Arctic
Post by: Archimid on March 28, 2018, 05:46:16 AM
The Arctic reaching 20-30C after a few blue ocean events, you guys lost it  ;D

 Sunlight is not enough to get the Arctic to 20C-30C but warm air transported over warm, ice free ocean is.  Please keep in mind, Arctic sea ice keeps the air near the surface cold. That cold air meets the warm air from the continents and keeps the continents cool during the summer. When the is gone, the continents will warm. 30C during summer is not very rare over the continents during the summer.  That air will transport into the warm ice less Arctic.

Quote
The Arctic will still be a deep ocean and not a shallow lagoon. Currently all heat goes into the top 1-2m of the ocean melting the ice. Even heat from subsurface water ends up into the top 1-2m. After the ice is gone the bottom heat source becomes a heatsink and you have to heat several tenth of meters of water to get a significant temperature increase.

And all that heat that used to go to melt ice now remains in the system for longer.

Quote
The heat loss to space also increases by the power of four for every degree more.

I'm not sure about this. How do you figure that increase?

Quote
With your imagination the always ice-free waters around Iceland would already be a tropical paradise.

Yeah, but with such long days imagine the sunburns!

hmm. Something occurs to me, what is the impact on temperatures of not having a night cycle?  The rest of the world gets at least some hours of night during summer. The ice less Arctic doesn't get that break.
Title: Re: Ice-free Arctic
Post by: crandles on March 28, 2018, 01:22:04 PM


This makes no sense. The first September have 0 ice. That means that growth started around November (according to the model) and then grew to such level that the extremely thin ice survived the next melting season with several million kilometers of ice to spare? Sorry but no. That is not realistic at all. I have never seen growth like that. Has anyone?
In fact the anemic growth of 2016, 2017 and 2018 prove that such fast growth is not necessarily true as the models assume.

So that response to peer reviewed science is basically 'I don't believe it'.
Quote
But wait, there is more:

(https://wol-prod-cdn.literatumonline.com/cms/attachment/37a757af-a0b4-46bd-8792-82fa8d25a30a/grl27655-fig-0003.png)

The paper calls this graph “Energy Budget of the Arctic Ocean Domain”. First let me say that it is a great graph, and the approach they took is elegant. I like the idea of the Arctic energy unit. However, the assumptions seem wrong after 2015. From September to March they have a net output of heat from the Arctic out to the planet. It seems to me that after 2015 that arrow was either reversed or significantly reduced.

Do you spot the triangle delta sign? That means difference in forcing so what they are saying is that when arctic is cold lots of heat gets transferred to the arctic. Now that it is warmer less heat gets transferred in so the difference is a net outgoing.

So this seems a case of you thinking peer reviewed science contains major mistakes when it is actually you failing to understand.
[/quote]
Title: Re: Ice-free Arctic
Post by: crandles on March 28, 2018, 02:15:36 PM

I disagree completely. This seems a case where yet again, peer reviewed science is not, has not been communicated to the public in a way that the public could ever understand!


I disagree completely.

Public outreach is important. However papers are not the way to do outreach. In papers the (only?) purpose is to write concisely in a way peers will understand.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 28, 2018, 02:22:29 PM

I disagree completely. This seems a case where yet again, peer reviewed science is not, has not been communicated to the public in a way that the public could ever understand!


I disagree completely.

Public outreach is important. However papers are not the way to do outreach. In papers the (only?) purpose is to write concisely in a way peers will understand.

Agreed.  Research publications are intended for other scientists, or those interests in the field.  Hence, the paper is often outside the comprehension of the general public. 
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 28, 2018, 02:39:11 PM

Yeah, but with such long days imagine the sunburns!

hmm. Something occurs to me, what is the impact on temperatures of not having a night cycle?  The rest of the world gets at least some hours of night during summer. The ice less Arctic doesn't get that break.

Perhaps we should look at real examples.  Located above the Arctic circle, and receiving 24 hours of sunlight for several weeks every year, Utqiavik (a.k.a. Barrow, Alaska) has experienced summer ice-free conditions for several years now, and has warmed considerably.  Using the most recent annual temperature and sea ice data (2017), we see that the ocean off the coast was ice-free from July through October, yet the temperature anomaly for that period was a mere 2C above average.  The temperature anomaly during the winter months was 10C above average.  The average annual increase was ~5C.  Granted this is not a direct comparison to what may occur over the open ocean.  However, one would expect some sort of correlation.

(https://s.w-x.co/wu/BRW_Anomalies-final.jpeg)

Title: Re: Ice-free Arctic
Post by: Archimid on March 28, 2018, 03:15:32 PM
Quote
So that response to peer reviewed science is basically 'I don't believe it'.

I don't care if an article is peer reviewed. It it contradicts my perception of reality I'll challenge it. This models predicts extraordinary growth that no one has ever witnessed before.

 I'll tell you exactly the mistake of the model.

The model assumes that after November, Arctic temperatures return to average. The average temps remain average even while generating record ice growth until April.

That's the opposite of the observations. So far the surface temperature anomalies last until April and ice has not grown at the incredible rate required by this model. There is something seriously wrong with it. The part of my reply that you didn't address explains why, let me repeat their assumption:

Quote
For SAT a large positive anomaly occurs between October and February after the initial perturbation, with a peak of almost 11 K in November (Figure 2). After February, there are no further SAT anomalies stronger than natural variability.

We are already at 5-8 K winter anomaly that last until April.  Yet you want me believe that after the first BOE all that extra heat will be vented out to of the arctic system? That makes no sense.

Quote
Do you spot the triangle delta sign? That means difference in forcing so what they are saying is that when arctic is cold lots of heat gets transferred to the arctic. Now that it is warmer less heat gets transferred in so the difference is a net outgoing.

huh? I'm not contradicting those basic physics. I'm, saying that even if the temperature gradient is smaller, leading to a net heat output, hot air intrusions from the oceans and continents have so far overwhelmed the cooling forcing of a smaller temperature difference. 

Of course this model, like most models I've seen, ignore the changes in atmospheric currents.
Title: Re: Ice-free Arctic
Post by: Archimid on March 28, 2018, 03:24:30 PM
we see that the ocean off the coast was ice-free from July through October, yet the temperature anomaly for that period was a mere 2C above average.

Because there is a huge chunk of ice a few thousand miles to the north interacting with southern heat. When there is no ice, the anomalies will change drastically.
Title: Re: Ice-free Arctic
Post by: Archimid on March 28, 2018, 03:27:14 PM
Frankly I'm becoming more convinced that the global models are slightly overestimating global temperatures because they are highly underestimating sea ice loss.
Title: Re: Ice-free Arctic
Post by: Daniel B. on March 28, 2018, 04:34:22 PM
we see that the ocean off the coast was ice-free from July through October, yet the temperature anomaly for that period was a mere 2C above average.

Because there is a huge chunk of ice a few thousand miles to the north interacting with southern heat. When there is no ice, the anomalies will change drastically.

And what if Barrow is not in fact a correlation to the whole Arctic Ocean with under 1 m2klms of ASI but is in fact an outlier variant?

Some supporting evidence and solid reasoning for such a claim would be helpful.

The temperature anomaly in Barrow is not an outlier.  The mean temperature north of 80 degrees has increased significantly in every winter over the past decade, while exhibiting a very slight decrease during the summer.   

http://ocean.dmi.dk/arctic/meant80n.uk.php (http://ocean.dmi.dk/arctic/meant80n.uk.php)

Title: Re: Ice-free Arctic
Post by: Archimid on March 28, 2018, 04:43:03 PM
Quote
The temperature anomaly in Barrow is not an outlier.  The mean temperature north of 80 degrees has increased significantly in every winter over the past decade, while exhibiting a very slight decrease during the summer. 

And the summer temperatures will not increase significantly until the ice is gone.
Title: Re: Ice-free Arctic
Post by: crandles on March 28, 2018, 05:09:14 PM
As far as I am concerned, advancing the science is almost everything and while there are a few other things like public outreach these are likely best done outside of the papers aimed at advancing science.

Sorry but just because you want public outreach to be treated as a top priority, doesn't necessarily mean you deserve it.
Title: Re: Ice-free Arctic
Post by: Archimid on March 28, 2018, 05:37:57 PM
Quote
As far as I am concerned, advancing the science is almost everything and while there are a few other things like public outreach these are likely best done outside of the papers aimed at advancing science.

The more easily understood is your research, the more outreach you will get. However at the higher levels of science, like peer reviewed literature precision and accuracy are a higher priority than understandability.

Peer review is important, but what happens when peers are wrong? Science advances.

I will like to say that the assumptions made in the paper I quoted were extremely good at the time they were made.

[timeTravelTo(2011)]

Yes 2007 was a record low volume but look at that growth rate! Volume is growing like it never has. Better yet, look at the winter surface temperatures anomalies. The heat disappears by November and then is just record ice growth.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Focean.dmi.dk%2Farctic%2Fplots%2FmeanTarchive%2FmeanT_2010.png&hash=87a4ba3ca6eab0b872bfe66f4a1078ac)

[timeTravelTo(now)]

The same argument could have been made all the way to 2014. The model was accurate for the knowledge of the time.

Then the last three years (and ongoing) happened. Record ice growth ceased. Temperature anomalies are not "venting" the heat out. By November the Arctic doesn't return to normal.
Title: Re: Ice-free Arctic
Post by: Alexander555 on March 28, 2018, 07:52:43 PM
Perhaps we should look at real examples.  Located above the Arctic circle, and receiving 24 hours of sunlight for several weeks every year, Utqiavik (a.k.a. Barrow, Alaska) has experienced summer ice-free conditions for several years now, and has warmed considerably.  Using the most recent annual temperature and sea ice data (2017), we see that the ocean off the coast was ice-free from July through October, yet the temperature anomaly for that period was a mere 2C above average.  The temperature anomaly during the winter months was 10C above average.  The average annual increase was ~5C.  Granted this is not a direct comparison to what may occur over the open ocean.  However, one would expect some sort of correlation.


I think it will be pretty hard to defend your point Archimid, 20 to 30 degree C at the Arctic. Even at the Equator its not 30 C today, above the sea. I think Daniels example gives a good indication. Something like 2 C warmer if the sea becomes ice-free in summer. And like you say, if all the ice is gone, the wind will become a little warmer. And it's hard to say how much, because that wind will have to travel a long distance. Otherwise he want be that warm.  But lets say another 1 to 2 degree C. And the average temperature today is only something like 1 C. That makes 5 degree C. Lets add an extreme heatwave in Europe or Africa, moving in the right direction, and you maybe have 6 degree C. And i think everything above that will be a long and slow proces. Because you still have a long winter without sunlight. So almost everything has to come by air or sea from the rest of the planet.
Title: Re: Ice-free Arctic
Post by: Archimid on March 28, 2018, 10:37:49 PM
I agree that 20C-30C is hard to justify. My first instinct was 10C-20C but then I checked out max temperatures over Siberia and decided to go with the higher range. There will definitely be segments of the Arctic that may hit daily 30C temps occasionally, but not Arctic wide and not for very long.
Title: Re: Ice-free Arctic
Post by: Iceismylife on March 28, 2018, 11:25:18 PM
My assumptions justifying thinking the gulf stream will find its way into the arctic ocean.

1. A BOE will let the stratification of the arctic ocean be disrupted by wave action.

2. when the sun sets and things cool off with the stratification a thing of the past you get bottom water production rather than ice.

3. what drives the currents around Greenland and the CAA currently is the Earth's rotation the warmth coming up from the equator (gulf stream) and the large freshwater input from ice melt and run off.

4. it is the cold reduced salinity run off water plus ocean water surface water current that pushes the gulf stream away from the east coat of north America.

The freshwater mixes with surface water, if that becomes bottom water then the surface water needs to be replaced.  The cold water would sink rather than stay on the surface.  So instead of a current coming out of the arctic ocean past Greenland you would have a current going in instead.

No current pushing the gulf stream east.  So it would go north into the arctic ocean.

With 20C water coming into the arctic basin you could see 20C air temps over the water and storms like there was no tomorrow.
Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 28, 2018, 11:27:58 PM
I don't care if an article is peer reviewed. It it contradicts my perception of reality I'll challenge it. This models predicts extraordinary growth that no one has ever witnessed before.

 I'll tell you exactly the mistake of the model.

The model assumes that after November, Arctic temperatures return to average. The average temps remain average even while generating record ice growth until April.

That's the opposite of the observations. So far the surface temperature anomalies last until April and ice has not grown at the incredible rate required by this model. There is something seriously wrong with it. The part of my reply that you didn't address explains why, let me repeat their assumption:

Quote
For SAT a large positive anomaly occurs between October and February after the initial perturbation, with a peak of almost 11 K in November (Figure 2). After February, there are no further SAT anomalies stronger than natural variability.

We are already at 5-8 K winter anomaly that last until April.  Yet you want me believe that after the first BOE all that extra heat will be vented out to of the arctic system? That makes no sense.

The record low ice extent to date was in 2012.  Here's how the 80N temperatures responded (note the below average temperatures in February):

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Focean.dmi.dk%2Farctic%2Fplots%2FmeanTarchive%2FmeanT_2013.png&hash=5c9caa814addcc02aca5d9156ab29b0e)

The sea ice extent in 2012 bottomed out at 3.39 million square kilometers.  In 2013 the minimum was 5.05 million square kilometers.  So somehow, 1.66 million square kilometers of exceedingly thin first year ice survived.
Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 28, 2018, 11:41:04 PM
My assumptions justifying thinking the gulf stream will find its way into the arctic ocean.

1. A BOE will let the stratification of the arctic ocean be disrupted by wave action.

2. when the sun sets and things cool off with the stratification a thing of the past you get bottom water production rather than ice.

3. what drives the currents around Greenland and the CAA currently is the Earth's rotation the warmth coming up from the equator (gulf stream) and the large freshwater input from ice melt and run off.

4. it is the cold reduced salinity run off water plus ocean water surface water current that pushes the gulf stream away from the east coat of north America.

The freshwater mixes with surface water, if that becomes bottom water then the surface water needs to be replaced.  The cold water would sink rather than stay on the surface.  So instead of a current coming out of the arctic ocean past Greenland you would have a current going in instead.

No current pushing the gulf stream east.  So it would go north into the arctic ocean.

With 20C water coming into the arctic basin you could see 20C air temps over the water and storms like there was no tomorrow.

Climate models show that a slow down of the Gulf Stream (actually the Atlantic Meriodonal Overturning Current, or AMOC) is more likely due to global warming.  There's a good summary of it here:  https://e360.yale.edu/features/will_climate_change_jam_the_global_ocean_conveyor_belt (https://e360.yale.edu/features/will_climate_change_jam_the_global_ocean_conveyor_belt)

Quote
A huge amount of heat is moved around our planet by a single ocean current system — the Atlantic Meridional Overturning Circulation (AMOC) — which accounts for up to a quarter of the planet’s heat flux. The system is driven by density: waters that are cold or salty are denser and so dive down to the ocean floor. As a result, today, cold waters sink in the North Atlantic and flow southwards, while warm tropical waters at the surface flow northwards in the Gulf Stream, making northern Europe unusually mild for its latitude. But if northern waters get too warm, or too fresh from melting ice, then they can stop being dense enough to sink. That causes a major traffic jam for the water attempting to move north, and the system grinds to a halt.

...

If the North Atlantic current slows dramatically, then the entire Northern Hemisphere would cool; a complete collapse of the current could even reverse global warming for about 20 years. But the heat that ocean currents fail to transport northwards would make parts of the Southern Hemisphere even hotter. And a cooler north isn’t necessarily good news. Should the AMOC shut down, models show that changes in rainfall patterns would dry up Europe’s rivers, and North America’s entire Eastern Seaboard could see an additional 30 inches of sea level rise as the backed-up currents pile water up on East Coast shores.
Title: Re: Ice-free Arctic
Post by: Archimid on March 29, 2018, 12:17:46 AM
Quote
The sea ice extent in 2012 bottomed out at 3.39 million square kilometers.  In 2013 the minimum was 5.05 million square kilometers.

The 2012-2013 freezing season had the record volume gain at the time at 19.063 x 1000km^2. Then it lost 17.04 during the melting season for a total volume gain of 1.79, year over year. In that cycle the Arctic grew. The 2013-2014 freezing season was much weaker at 17.726 but the melting season was the weakest since 2007 for a net year over year gain of 1.42.

In both years the gains exceeded the losses thus we had two years in a row of volume growth. But only in one of those years was record gains obtained.

Both 2016 and 2017 had similarly low volumes but they only gained 17.031. For both seasons winter temperatures remained highly anomalously warm for the whole season.
Title: Re: Ice-free Arctic
Post by: Iceismylife on March 29, 2018, 02:11:54 AM

...

Climate models show that a slow down of the Gulf Stream (actually the Atlantic Meriodonal Overturning Current, or AMOC) is more likely due to global warming.  There's a good summary of it here:
...
climate models are based on assumptions.  I don't forget 2012 reaching the median prediction for 2100 in sea ice extent.  I am not impressed with models predictive ability.  (I predicted that Katrina would turn and hit New Orleans when they had it hitting Mexico.  The same with the next one.  I said the next one would go straight they said it would turn and it did. I was 2 for 3 they were 1 for 3)

Nice article. 

Has anyone modeled open water in the arctic?

Title: Re: Ice-free Arctic
Post by: crandles on March 29, 2018, 12:41:45 PM

...

Climate models show that a slow down of the Gulf Stream (actually the Atlantic Meriodonal Overturning Current, or AMOC) is more likely due to global warming.  There's a good summary of it here:
...
climate models are based on assumptions.  I don't forget 2012 reaching the median prediction for 2100 in sea ice extent.  I am not impressed with models predictive ability.  (I predicted that Katrina would turn and hit New Orleans when they had it hitting Mexico.  The same with the next one.  I said the next one would go straight they said it would turn and it did. I was 2 for 3 they were 1 for 3)

Nice article. 

Has anyone modeled open water in the arctic?

Perhaps see
https://forum.arctic-sea-ice.net/index.php/topic,2286.msg560/
Title: Re: Ice-free Arctic
Post by: johnm33 on March 29, 2018, 01:07:11 PM
My assumptions justifying thinking the gulf stream will find its way into the arctic ocean.

1. A BOE will let the stratification of the arctic ocean be disrupted by wave action.

2. when the sun sets and things cool off with the stratification a thing of the past you get bottom water production rather than ice.

3. what drives the currents around Greenland and the CAA currently is the Earth's rotation the warmth coming up from the equator (gulf stream) and the large freshwater input from ice melt and run off.

4. it is the cold reduced salinity run off water plus ocean water surface water current that pushes the gulf stream away from the east coat of north America.

The freshwater mixes with surface water, if that becomes bottom water then the surface water needs to be replaced.  The cold water would sink rather than stay on the surface.  So instead of a current coming out of the arctic ocean past Greenland you would have a current going in instead.

No current pushing the gulf stream east.  So it would go north into the arctic ocean.

With 20C water coming into the arctic basin you could see 20C air temps over the water and storms like there was no tomorrow.
I see 3/4 very differently, take a look at the currents here  (https://earth.nullschool.net/#current/ocean/surface/currents/orthographic=-14.37,1.90,284) water rises off of Africa and whether due to coming from the deep, or from nearer the poles, is moving slower than the Earth, it is driven west. It ends up in the Carribean where it overflows and moves north, the surface speed (https://68.media.tumblr.com/f6959257bf4c7b28be5a0da1ae16a52a/tumblr_mzv5b7Sljz1s3dn7vo1_1280.png) rapidly changes as the water moves north, but the water still slower hugs the coast, then @350 or thereabouts the waters inertia is faster than surface speed and separates from the coast, flowing east.
 From there its path is determined by the path of least resistance, if there was no net flow from the Arctic either as fresher water coming down through Labrador, or strongly saline falling into the deep, Denmark strait etc., there'd be no physical reason for that water to move north. Despite some metrics to the contrary the evidence of more Gulf waters penetrating deeper into the  Arctic speaks to an accelerated rate of turnover.
I don't think it's useful to make any particular case since so many variables are in play, but I do expect to see a tidal signature emerging and contributing to the destruction of the ice this year, more on the Atlantic side but not confined to it.
Title: Re: Ice-free Arctic
Post by: Iceismylife on March 29, 2018, 06:12:23 PM
I see 3/4 very differently, take a look at the currents here  (https://earth.nullschool.net/#current/ocean/surface/currents/orthographic=-14.37,1.90,284) water rises off of Africa and whether due to coming from the deep, or from nearer the poles, is moving slower than the Earth, it is driven west. It ends up in the Carribean where it overflows and moves north, the surface speed (https://68.media.tumblr.com/f6959257bf4c7b28be5a0da1ae16a52a/tumblr_mzv5b7Sljz1s3dn7vo1_1280.png) rapidly changes as the water moves north, but the water still slower hugs the coast, then @350 or thereabouts the waters inertia is faster than surface speed and separates from the coast, flowing east.
 From there its path is determined by the path of least resistance, if there was no net flow from the Arctic either as fresher water coming down through Labrador, or strongly saline falling into the deep, Denmark strait etc., there'd be no physical reason for that water to move north. Despite some metrics to the contrary the evidence of more Gulf waters penetrating deeper into the  Arctic speaks to an accelerated rate of turnover.
I don't think it's useful to make any particular case since so many variables are in play, but I do expect to see a tidal signature emerging and contributing to the destruction of the ice this year, more on the Atlantic side but not confined to it.
A blue ocean event means more heat transfer from the water to the environment.  That means one of two things.  More ice production or more bottom water production.  Accelerated rate of turnover that is what I think will happen.

Bottom water generation in the CAB means the surface water will come from somewhere else. 



 Here  (https://earth.nullschool.net/#current/ocean/surface/currents/overlay=sea_surface_temp/orthographic=-17.54,61.69,537) is where I've been looking.   You've talked about flow separation.  The Gulf Stream separates about @350. If you pull surface water north into the CAB then you should pull the Gulf Stream too.  Boundary layer control.
Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 29, 2018, 07:37:33 PM
Quote
The sea ice extent in 2012 bottomed out at 3.39 million square kilometers.  In 2013 the minimum was 5.05 million square kilometers.

The 2012-2013 freezing season had the record volume gain at the time at 19.063 x 1000km^2. Then it lost 17.04 during the melting season for a total volume gain of 1.79, year over year. In that cycle the Arctic grew. The 2013-2014 freezing season was much weaker at 17.726 but the melting season was the weakest since 2007 for a net year over year gain of 1.42.

In both years the gains exceeded the losses thus we had two years in a row of volume growth. But only in one of those years was record gains obtained.

Both 2016 and 2017 had similarly low volumes but they only gained 17.031. For both seasons winter temperatures remained highly anomalously warm for the whole season.

Volume has increased despite the warmer winters:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fpsc.apl.uw.edu%2Fwordpress%2Fwp-content%2Fuploads%2Fschweiger%2Fice_volume%2FBPIOMASIceVolumeAnomalyCurrentV2.1_CY.png&hash=71e098ee33c36296b9e24f63de218d71)

It just might be because even as "warm" as the previous winters have been, they haven't come close to reaching the melt point of ice:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Focean.dmi.dk%2Farctic%2Fplots%2FmeanTarchive%2FmeanT_2017.png&hash=59eb65f128ffbe7ae10e4673b1a7d998)
Title: Re: Ice-free Arctic
Post by: Archimid on March 29, 2018, 11:30:42 PM
Quote
It just might be because even as "warm" as the previous winters have been, they haven't come close to reaching the melt point of ice:

The thermodynamic ice thickness growth rate is a function of time and temperature. The metric used to calculate that function is the Freezing Degree Day. You can read about it here:

 https://nsidc.org/cryosphere/seaice/processes/thermodynamic_growth.html

 Tealight has a nice set of graphs describing FDD behavior over the last several years here:

https://sites.google.com/site/cryospherecomputing/fdd

Quote
Volume has increased despite the warmer winters:

Do you mean 2017/2018 volume increased relative to 2016/2017? Of course. See the FDD graphs above. 2016/17 was the warmest winter on record, so it follows that that it had a very low volume gain. Luckily, 2017 had the second smallest volume loss since 2014. That left the volume minimum in a good position to overtake 2017/2018 even if it was almost as warm.

2017/2018 my yet surprise. If the Bering situation results in a chukchi/beufort/ess situation, Volume Maximum might reach record low.
Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 30, 2018, 01:23:38 AM
Quote
It just might be because even as "warm" as the previous winters have been, they haven't come close to reaching the melt point of ice:

The thermodynamic ice thickness growth rate is a function of time and temperature. The metric used to calculate that function is the Freezing Degree Day. You can read about it here:

 https://nsidc.org/cryosphere/seaice/processes/thermodynamic_growth.html

 Tealight has a nice set of graphs describing FDD behavior over the last several years here:

https://sites.google.com/site/cryospherecomputing/fdd

Quote
Volume has increased despite the warmer winters:

Do you mean 2017/2018 volume increased relative to 2016/2017? Of course. See the FDD graphs above. 2016/17 was the warmest winter on record, so it follows that that it had a very low volume gain. Luckily, 2017 had the second smallest volume loss since 2014. That left the volume minimum in a good position to overtake 2017/2018 even if it was almost as warm.

2017/2018 my yet surprise. If the Bering situation results in a chukchi/beufort/ess situation, Volume Maximum might reach record low.

Tealight's graphs seem to undercalculate the thickness of the ice.  Compare the graph, which calculates a current ice thickness of 150 cm to the map showing the current ice thickness:

(https://lh3.googleusercontent.com/BvkObeX59RNa2SgpZP3MAG6gI6eLgus5R9cGS8Fj2JEcmEnbyZI5W8vq7RtxIvE0XGejJhh-_g=w1680-h905)Tealight's graph.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Focean.dmi.dk%2Farctic%2Ficethickness%2Fanim%2Fplots_uk%2FCICE_combine_thick_SM_EN_20180328.png&hash=2aee4164e22d11c2080feecac8fb6e46) Current ice thickness and volume from DMI

It seems that the simple formula leaves out a lot of real life situations.  Here's what NSIDC says on the page you linked: 
Quote
The ice thickness increases at a rate roughly proportional to the square root of the cumulative FDD. Formulas such as this are empirical, meaning they are calculated only with observed data, so they really are simplifications of the ice growth processes. The formulas assume that the ice growth occurs in calm water and is reasonably consistent, and they do not take into account sea ice motion, snow cover, and other surface conditions.

NSIDC has a good page summarizing how sea ice forms.  Here's a link:https://nsidc.org/cryosphere/seaice/characteristics/formation.html (https://nsidc.org/cryosphere/seaice/characteristics/formation.html)

The wind and waves can cause forming ice sheets to raft over each other (becoming thicker) and crash into each other, forming ridges. From the link above:

Quote
If the ocean is rough, the frazil crystals accumulate into slushy circular disks, called pancakes or pancake ice, because of their shape. A signature feature of pancake ice is raised edges or ridges on the perimeter, caused by the pancakes bumping into each other from the ocean waves. If the motion is strong enough, rafting occurs. If the ice is thick enough, ridging occurs, where the sea ice bends or fractures and piles on top of itself, forming lines of ridges on the surface. Each ridge has a corresponding structure, called a keel, that forms on the underside of the ice. Particularly in the Arctic, ridges up to 20 meters (60 feet) thick can form when thick ice deforms.
Title: Re: Ice-free Arctic
Post by: Archimid on March 30, 2018, 03:02:39 AM
Quote
Tealight's graphs seem to undercalculate the thickness of the ice.  Compare the graph, which calculates a current ice thickness of 150 cm to the map showing the current ice thickness:

yes of course and he says so on his site:

Quote
It is important to note that the calculated thickness using this formula only accounts for the freezing of sea water and not ice growth from snowfall, freezing rain or ridging

FDD calculations alone are not meant to determine the exact thickness of the ice. However, they do show the potential temperature based thickness of the ice. Like all data, you have to take it for what it is.

What I want you to understand is that ice formation is not a binary function "below freezing", "not below freezing". Ice formation speeds up the colder it is. FDD's as illustrated by Tealight show how Arctic winter temperatures increased over time.
Title: Re: Ice-free Arctic
Post by: crandles on March 30, 2018, 12:08:55 PM
What I want you to understand is that ice formation is not a binary function "below freezing", "not below freezing". Ice formation speeds up the colder it is. FDD's as illustrated by Tealight show how Arctic winter temperatures increased over time.


But aren't higher temperatures a sign of higher hear transfer from the ocean and heat transfer from the ocean is a pretty direct measure of ice formation (once and surplus heat built up over summer has been vented)?

Resolving cause and effect can be tricky.

If you are believing the major mechanisms are GHGs control air temperatures and temperatures control heat loss from ocean which controls ice formation then you are ignoring a different directional causation:

Heat loss from ocean controls both the air temperature and ice formation.

If the major causation direction was GHGs controlling temperatures then temperature rises would be more throughout the year. I think the temperatures rises are greatest when the ice is thinner than normal. eg 2017 maximum ice particularly low and winter temperatures were high. So I think the major direction of causation is from heat loss from oceans. Not saying there isn't some causation effect of air temperatures but it doesn't seem like the main causation direction.

Edit: This is probably dangerous reasoning is the temp high because the ice is thin or is the ice thin because the temps are high? Better reasoning might involve figuring out which comes first.
Title: Re: Ice-free Arctic
Post by: Archimid on March 30, 2018, 02:45:08 PM
Quote
But aren't higher temperatures a sign of higher hear transfer from the ocean and heat transfer from the ocean is a pretty direct measure of ice formation (once and surplus heat built up over summer has been vented)?

I think a key point of my argument is that a significant portion of the extra heat is not being vented outside the Arctic system, changing both temperatures and gradients between the atmosphere and the oceans. At least not in the last three years of record hot winter temperatures.

Quote
If you are believing the major mechanisms are GHGs control air temperatures and temperatures control heat loss from ocean which controls ice formation then you are ignoring a different directional causation:

GHG's are certainly important, but the biggest change in heat transfers right now seems to be advection from the peripheral atmosphere into the Arctic. I think the changes in the atmospheric currents increase the exchange of heat between the Arctic and the rest of the Northern hemisphere resulting in a much warmer arctic and a slightly cooler rest of the world. I think that's why global models are slightly overestimating global warming but Arctic models are strongly underestimating sea ice losses. 

Quote
Heat loss from ocean controls both the air temperature and ice formation.

I can certainly agree that other than the sun (or lack thereof), ocean temperatures and heat transfers from ocean to atmosphere are one of the most important factors in Arctic temperatures.

Quote
If the major causation direction was GHGs controlling temperatures then temperature rises would be more throughout the year.

I think the causation line goes like this

1. GHG's cause global warming->
2. Global warming causes changes in the atmospheric currents->
3. Changes in the atmospheric currents cause an increase in advection into the Arctic->
4. Increase advection results in changes of the ice->
5. Changes of the ice cause changes in atmospheric currents->
6. Go Back to 3

Quote
I think the temperatures rises are greatest when the ice is thinner than normal.

Agreed.

Quote
So I think the major direction of causation is from heat loss from oceans

I think heat loss from the oceans will increase in impact as the ice gets thinner and is gone for longer.  There will be more heat entering the ocean  in summer. That heat will vent in to the atmosphere raising temperatures and slowing down ice growth. Some of that heat will go out into space, but a significant portion stays in the climate system becoming a positive feedback for temperature.

Quote
This is probably dangerous reasoning is the temp high because the ice is thin or is the ice thin because the temps are high? Better reasoning might involve figuring out which comes first.

Both are true, but the cycle started with higher temperatures turning ice thin.
Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 30, 2018, 06:06:04 PM
What I want you to understand is that ice formation is not a binary function "below freezing", "not below freezing". Ice formation speeds up the colder it is. FDD's as illustrated by Tealight show how Arctic winter temperatures increased over time.

This statement is incorrect.  Ice formation is a binary function of below freezing and not below freezing.  Once seawater gets below the freezing point, -1.8 C, ice crystals will form.  It's basic physics.

After that, sea ice thickness is determined by other factors, including wind and snow.  Wind and snow help thicken the ice sheet.  The wind by allowing more heat to dissipate through the ice, and snow by weighing down the ice and allowing more snow ice to form.

Snow also helps to protect the ice during the melt season through it's higer albedo.  Here's a link to a paper about observations of snow on ice during the 2015 spring:  https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2017GL075494 (https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2017GL075494)

From the introduction of the paper: 
Quote
Snow on sea ice is a critical physical parameter that modulates the growth and decay of sea ice (Maykut, 1978; Sturm & Massom, 2010). In spring, when solar insolation is high, even little snow fall on Arctic sea ice can significantly slow down surface melt, due to the snow’s high albedo (Perovich et al., 2017). In winter, when sea ice grows in the absence of solar insolation in the high Arctic, the role of snow is twofold. Snow insulates the sea ice surface from cold air temperatures, hindering thermodynamic growth of sea ice (Ledley, 1991; Maykut, 1978). However, snow can also contribute to the sea ice mass balance through the formation of snow-ice (e.g., Leppäranta, 1983). Snow-ice forms when seawater floods and refreezes at the ice/snow interface, due to excessive snow load that pushes the ice surface below sea level. Snow-ice is a common process in seasonally ice-covered seas but has not been prevalent in the Arctic, where thick perennial sea ice has dominated (Sturm & Massom, 2010).

So a few degrees of warming during the winter, provided that the temperatures stay below freezing (resulting in new ice crystals forming in leads and snow falling on that ice), don't prevent new ice from forming.  That's why models predict that the Arctic will become a seasonal ice sheet (similar to Antarctica or the Sea of Okhotsk), not ice free all year.
Title: Re: Ice-free Arctic
Post by: Archimid on March 30, 2018, 06:22:53 PM
Quote
This statement is incorrect.  Ice formation is a binary function of below freezing and not below freezing.  Once seawater gets below the freezing point, -1.8 C, ice crystals will form.  It's basic physics.

Are you arguing that temperatures have no significant bearing on ice formation rate?

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After that, sea ice thickness is determined by other factors, including wind and snow.  Wind and snow help thicken the ice sheet.  The wind by allowing more heat to dissipate through the ice, and snow by weighing down the ice and allowing more snow ice to form.

Woosh. Most ice formation is due to bottom growth. That growth is completely dependent on the gradient of temperature of the water with the atmosphere. The colder it is the larger the gradient producing more ice.

Of course, snow and frozen rain do add to the total but that number is much smaller than bottom growth.

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Snow also helps to protect the ice during the melt season through it's higer albedo.  Here's a link to a paper about observations of snow on ice during the 2015 spring:


Did you even read that abstract to the end? Read the last sentence.

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So a few degrees of warming during the winter, provided that the temperatures stay below freezing (resulting in new ice crystals forming in leads and snow falling on that ice), don't prevent new ice from forming.  That's why models predict that the Arctic will become a seasonal ice sheet (similar to Antarctica or the Sea of Okhotsk), not ice free all year.

Sure a few degrees will of course result in almost unnoticeable effects but the warmer it gets the less growth you get through bottom melt.
Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 30, 2018, 08:51:24 PM
Quote
This statement is incorrect.  Ice formation is a binary function of below freezing and not below freezing.  Once seawater gets below the freezing point, -1.8 C, ice crystals will form.  It's basic physics.

Are you arguing that temperatures have no significant bearing on ice formation rate?

Quote
After that, sea ice thickness is determined by other factors, including wind and snow.  Wind and snow help thicken the ice sheet.  The wind by allowing more heat to dissipate through the ice, and snow by weighing down the ice and allowing more snow ice to form.

Woosh. Most ice formation is due to bottom growth. That growth is completely dependent on the gradient of temperature of the water with the atmosphere. The colder it is the larger the gradient producing more ice.

Of course, snow and frozen rain do add to the total but that number is much smaller than bottom growth.

Quote
Snow also helps to protect the ice during the melt season through it's higer albedo.  Here's a link to a paper about observations of snow on ice during the 2015 spring:


Did you even read that abstract to the end? Read the last sentence.

Quote
So a few degrees of warming during the winter, provided that the temperatures stay below freezing (resulting in new ice crystals forming in leads and snow falling on that ice), don't prevent new ice from forming.  That's why models predict that the Arctic will become a seasonal ice sheet (similar to Antarctica or the Sea of Okhotsk), not ice free all year.

Sure a few degrees will of course result in almost unnoticeable effects but the warmer it gets the less growth you get through bottom melt.

The thickness maps show ice 3 to 4 meters thick in areas north of 80N, where the temperatures have been been warmer in winter.  So I'm arguing that the effects of rafting, ridging and snow ice formation can offset the slower bottom growth from the above average temperatures and delay the complete melt out of the Arctic ice.  These mechanisms will also allow the Arctic ice the reform in winters after it eventually goes ice-free in summers, becoming a seasonal ice sheet, like the Antarctic sea ice.

And I did read the entire article, not just the abstract.  With more storms, you get more snow on the thinner ice.  That leads to more snow-ice formation and the protective albedo effect.  From the discussion section of the article that explains the last sentence of the abstract (emphasis added):

Quote
Mean precipitation from 1980 to 2016 shows the highest precipitation in the Atlantic sector of the Arctic (Figure S2b). This region is characterized by a larger number of autumn and winter storm events (Graham, Rinke, et al., 2017; Graham, Cohen, et al., 2017; Rinke et al., 2017; Woods & Caballero, 2016; Zhang et al., 2004). This is largely due to the influence of North Atlantic Ocean. High precipitation in this region is supported by the deep (>50 cm) snowpacks observed in this region during spring field campaigns in 2015 (Merkouriadi, Gallet, Graham, et al., 2017) and 2017 (M. Granskog; M. Nicolaus, personal communication, 2017). Given the recent observations of thicker snow cover and thinning of the ice cover in the Atlantic sector
of the Arctic (Renner et al., 2014; Rösel, Divine, et al., 2016; Rösel, Polashenski, et al., 2016), we surmise the potential for snow-ice formation in this region is the largest in the Arctic Ocean but can become imminent in larger areas when the ice is thinning.

In autumn and winter of 2014–2015, frequent storm events brought heavy precipitation and positive air temperature anomalies to our study region (Figures 1a and 1b). These storms are also associated with sustained 6-hourly wind speeds above 10 m s1, according to the ERA-I reanalysis (Merkouriadi, Gallet, Graham, et al., 2017). These strong winds initially come from the south and advect warm and moist air from the North Atlantic into the Central Arctic, resulting in heavy precipitation and positive temperature anomalies (Cohen et al., 2017; Kayser et al., 2017; Woods & Caballero, 2016). It is clear from our results that these storm events, and associated precipitation and temperature changes, play a crucial role in the growth, development, and structure of FYI. The impact of these storms in relation to the growth onset of FYI needs to be considered in sea ice modeling studies.
Title: Re: Ice-free Arctic
Post by: Archimid on March 30, 2018, 09:15:04 PM
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The thickness maps show ice 3 to 4 meters thick in areas north of 80N

That's mostly due to multiyear ice accumulating yearly excess ice.

I'll ask again, because you are making it sound like temperatures don't matter for ice formation, when I believe it is the major component of ice formation. Yet you are not saying it straight up, you are simply dancing around it. I'm very confused.

To your understanding, does it matter how cold it gets or is it simply enough to reach the minimum freezing point? If it does matter, what percentage of the ice is made through bottom growth and what percentage is made by snow/rain/ridging.
Title: Re: Ice-free Arctic
Post by: Ken Feldman on March 31, 2018, 12:54:49 AM
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The thickness maps show ice 3 to 4 meters thick in areas north of 80N

That's mostly due to multiyear ice accumulating yearly excess ice.

I'll ask again, because you are making it sound like temperatures don't matter for ice formation, when I believe it is the major component of ice formation. Yet you are not saying it straight up, you are simply dancing around it. I'm very confused.

To your understanding, does it matter how cold it gets or is it simply enough to reach the minimum freezing point? If it does matter, what percentage of the ice is made through bottom growth and what percentage is made by snow/rain/ridging.

Both are important, but ridging and rafting is obviously capable of adding more thickness than thermodynamic processes.  This is from a site on the Antartic sea ice, but the physical processes are the same:

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Analysis of the pack shows that deformation, rather than basal freezing, is the dominant mechanism for increasing ice thickness beyond 0.2-0.4 m. This results in an increase in local ice thickness whilst at the same time opening leads where, during the growth season, new ice is able to form. The net effect is increased ice production resulting in an increase in the total mass of ice within the pack, and subsequent changes in the ice thickness distribution.
 

Here's a link to the site:  http://aspect.antarctica.gov.au/home/about-sea-ice/ridging-and-rafting (http://aspect.antarctica.gov.au/home/about-sea-ice/ridging-and-rafting)

And here's a follow-up to the paper on storms in the North Atlantic helping the ice to grow:

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As the Arctic sea ice cover continues to thin, convergent sea ice motion can more readily pile up ice into large ridges. Such ridges can be hazardous to marine activities in the Arctic. Divergent ice motion produces openings in the ice called leads, where new ice can readily grow. Winds are the main driver for both ridging and lead formation. A single storm event can lead to significant redistribution of sea ice mass through ridging and new leads. As part of the Norwegian Young Sea ICE (N-ICE2015) expedition, colleagues at the Norwegian Polar Institute made detailed sea ice thickness and ice drift observations before and after a storm in an area north of Svalbard (Figure 5). Results showed that about 1.3 percent of the level sea ice volume was pressed together into ridges. Combined with new ice formation in leads, the overall ice volume increased by 0.5 percent. While this is a small number, sea ice in the North Atlantic is typically impacted by 10 to 20 storms each winter, which could account for 5 to 10 percent of ice volume each year.
  The source for that story is the NSIDC website at this link: http://nsidc.org/arcticseaicenews/2018/02/ (http://nsidc.org/arcticseaicenews/2018/02/)



Title: Re: Ice-free Arctic
Post by: Archimid on March 31, 2018, 02:57:26 AM
Both are important, but ridging and rafting is obviously capable of adding more thickness than thermodynamic processes. 

That may be true for Antarctica, but as your second link measured, it is not the same for the arctic.

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This is from a site on the Antartic sea ice, but the physical processes are the same:

Similar in many ways, very different in others. I think the real big difference is that Antarctica is an ice sheet on top of the continent surrounded by the ocean. The center is ready an primed to grow with a gigantic ice sheet on top priming all the surrounding ocean with fresh water and very high albedo.

The Arctic is the polar opposite. An ocean covered in a sheet of ice surrounded by mostly land. The land no longer has ice on it except for Greenland. See NSIDC take on that.

https://nsidc.org/cryosphere/seaice/characteristics/difference.html

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Because sea ice does not stay in the Antarctic as long as it does in the Arctic, it does not have the opportunity to grow as thick as sea ice in the Arctic. While thickness varies significantly within both regions, Antarctic ice is typically 1 to 2 meters (3 to 6 feet) thick, while most of the Arctic is covered by sea ice 2 to 3 meters (6 to 9 feet) thick. Some Arctic regions are covered with ice that is 4 to 5 meters (12 to 15 feet) thick.

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And here's a follow-up to the paper on storms in the North Atlantic helping the ice to grow:
...
 Results showed that about 1.3 percent of the level sea ice volume was pressed together into ridges. Combined with new ice formation in leads, the overall ice volume increased by 0.5 percent. While this is a small number, sea ice in the North Atlantic is typically impacted by 10 to 20 storms each winter, which could account for 5 to 10 percent of ice volume each year.
 

So 5-10 percent in the peripheral seas. I bet much less in the inner basin.

Once the arctic is ice free the ice will probably form in a similar way as Antarctica. Except that in Antarctica the ice radiates out of a frozen continent while in the Arctic it will grow from the outside in with no ice sheet to help except for the northern coast of Greenland.


At the end of the year whatever ice is left will be 1 year ice of record low extent and volume. That ice will melt the following year even quicker than before, allowing more heat to enter the system, further delaying the freezing season. Rinse and repeat.

Title: Re: Ice-free Arctic
Post by: Shared Humanity on March 31, 2018, 07:47:02 PM
Once the arctic is ice free the ice will probably form in a similar way as Antarctica. Except that in Antarctica the ice radiates out of a frozen continent while in the Arctic it will grow from the outside in with no ice sheet to help except for the northern coast of Greenland.


At the end of the year whatever ice is left will be 1 year ice of record low extent and volume. That ice will melt the following year even quicker than before, allowing more heat to enter the system, further delaying the freezing season. Rinse and repeat.

I generally agree with this with regards to how the ice will behave when we reach a BOE at the end of the melt season. Since this is defined as less than 1 million square km, there will be still be rafts of dispersed floes randomly across the CAB that may even blink out on SIE measures as the concentrations are below 15%. There will also still be dispersed floes in concentrations high enough to be measured as extent in and about the CAA. Heading into the winter, the ice will then form pretty much as you described, along the shores but also around these patches of ice that remain after the melt season. In the polar winter, the growth in extent will be quite rapid although the physical characteristics will be quite different (pancake ice etc) due to storminess etc. Entering the next melt season, we will find ice across much/most of the CAB and in the peripheral seas, much as we do today with the exception that it will be thinner, more mobile and prone to melt out faster.

Wash, rinse, repeat than becomes seasonal BOE with winter ice cover that fails to meet the definition of BOE.

There is a very real possibility IMO that an odd equilibrium will exist where at the height of the freeze season you find large expanses of ice along the shores across the Arctic , with a violent, treacherous, ice filled, stormy, open ocean winter in the center of the CAB. Think Bering Sea but much nastier.
Title: Re: Ice-free Arctic
Post by: Iceismylife on March 31, 2018, 11:46:27 PM
...
There is a very real possibility IMO that an odd equilibrium will exist where at the height of the freeze season you find large expanses of ice along the shores across the Arctic , with a violent, treacherous, ice filled, stormy, open ocean winter in the center of the CAB. Think Bering Sea but much nastier.
...and that will bring in the heat of the gulf stream.
Title: Re: Ice-free Arctic
Post by: Shared Humanity on April 01, 2018, 07:09:49 PM
...
There is a very real possibility IMO that an odd equilibrium will exist where at the height of the freeze season you find large expanses of ice along the shores across the Arctic , with a violent, treacherous, ice filled, stormy, open ocean winter in the center of the CAB. Think Bering Sea but much nastier.
...and that will bring in the heat of the gulf stream.

Heat from the Pacific and Atlantic current is already being transported into the Arctic Ocean and if the Arctic Ocean were not as protected as it is from warmer waters, I think an all year long BOE could set up very soon but this is not the case. The continents protect the Arctic Ocean. It is not an accident that the peripheral seas that are protected by land freeze better than seas that are more open to warm water intrusions. The Kara Sea is further south than much of the Barents but it will freeze over while the Barents now remains substantially ice free through the winter. This is due to the protection that Novaya Zemlya provides it. The Beaufort, Chukchi and ESS are also further south than the Barents and we see the same thing. We will continue to observe the Arctic Ocean be protected in this manner in a rapidly warming world.
Title: Re: Ice-free Arctic
Post by: Shared Humanity on April 01, 2018, 07:18:31 PM
I do believe that BAU (or near BAU) for the remainder of the 21st century (a distinct possibility) could set us up for an eventual year long ice free Arctic Ocean but this will not occur in our lifetimes.
Title: Re: Ice-free Arctic
Post by: Wherestheice on April 01, 2018, 11:50:53 PM
I personally think that having the arctic ocean ice free year round is possible. Can't say when though...
Title: Re: Ice-free Arctic
Post by: Daniel B. on April 02, 2018, 04:33:15 PM
I do believe that BAU (or near BAU) for the remainder of the 21st century (a distinct possibility) could set us up for an eventual year long ice free Arctic Ocean but this will not occur in our lifetimes.

I concur with both your posts.  The land surrounding much of the Arctic waters offers isolation from warmer ocean waters.  This reduces summer melt and enhanced winter growth.  I doubt that the Arctic will ever become ice-free year round, as the physics of ice formation will remain.  When the first occurrence of a summer ice-free condition occurs is difficult to predict.  While it could happen in my lifetime, I suspect not (unless I reach the century mark).  The longer it takes to reach ice-free conditions, the better chance that humanity will will take the appropriate actions.
Title: Re: Ice-free Arctic
Post by: FrostKing70 on April 02, 2018, 07:02:55 PM
I agree, the long polar night will result in some ice formation during the winter, even when the world heats up substantially from today.   Year Long Ice Free (YLIF?) is not credible in our lifetimes.....

Also, what is BAU?
Title: Re: Ice-free Arctic
Post by: Daniel B. on April 02, 2018, 08:51:22 PM
BAU stands for business as usual.  In other words, no significant action to lower CO2 emissions.
Title: Re: Ice-free Arctic
Post by: oren on April 02, 2018, 11:09:43 PM
Also, what is BAU?
Business As Usual scenario, humanity continuing to burn fossil fuels with no real change in behavior. Same as it does today, more or less. (But with more people and more economic growth)
Title: Re: Ice-free Arctic
Post by: Iceismylife on April 02, 2018, 11:53:23 PM

...
Heat from the Pacific and Atlantic current is already being transported into the Arctic Ocean and if the Arctic Ocean were not as protected as it is from warmer waters, I think an all year long BOE could set up very soon but this is not the case.
...
Part of that protection is the stratification in the arctic ocean. Because of it ice formation doesn't lead to bottom water generation.  Mix up the stratification and have open water then you get bottom water.  Take the surface water and run it down to the bottom more surface water will replace it.  Surface water is on the surface because it has low density.  Cooling it or adding salt makes it denser.  (adding fresh water reduces density)  Overturn the water inside of the CAB and you pull in surface water to replace what was on the surface.

Title: Re: Ice-free Arctic
Post by: Coffee Drinker on April 07, 2018, 04:59:42 AM
My assumptions justifying thinking the gulf stream will find its way into the arctic ocean.

1. A BOE will let the stratification of the arctic ocean be disrupted by wave action.

2. when the sun sets and things cool off with the stratification a thing of the past you get bottom water production rather than ice.

3. what drives the currents around Greenland and the CAA currently is the Earth's rotation the warmth coming up from the equator (gulf stream) and the large freshwater input from ice melt and run off.

4. it is the cold reduced salinity run off water plus ocean water surface water current that pushes the gulf stream away from the east coat of north America.

The freshwater mixes with surface water, if that becomes bottom water then the surface water needs to be replaced.  The cold water would sink rather than stay on the surface.  So instead of a current coming out of the arctic ocean past Greenland you would have a current going in instead.

No current pushing the gulf stream east.  So it would go north into the arctic ocean.

With 20C water coming into the arctic basin you could see 20C air temps over the water and storms like there was no tomorrow.

Where would you get those 20C waters from? We hardly ever reach 20C in the North Sea even during those exceptionally hot and sunny summers we had in the 90s. And that's like 2000km south of what is considered arctic ocean.

Just wondering.
Title: Re: Ice-free Arctic
Post by: Gray-Wolf on April 07, 2018, 03:25:19 PM
Didn't we see near Med. temps in the McKenzie Delta back in 2012?

There is a lot of shallow shelf waters around the basin and 24/7 of sun over high summer might drive some big temp blooms?

If the rivers flowing into the basin are also coming out of scorched lands too then we might see high temps by mid aug?

Not sure of 20c though?
Title: Re: Ice-free Arctic
Post by: TerryM on April 07, 2018, 05:06:48 PM
Didn't we see near Med. temps in the McKenzie Delta back in 2012?

There is a lot of shallow shelf waters around the basin and 24/7 of sun over high summer might drive some big temp blooms?

If the rivers flowing into the basin are also coming out of scorched lands too then we might see high temps by mid aug?

Not sure of 20c though?


Yes.
At an island to the west, whose name escaped me, researchers were taking daily swims in the arctic ocean.
20c may not be high enough.
Terry
Title: Re: Ice-free Arctic
Post by: gerontocrat on April 13, 2018, 04:34:18 PM
I've been looking at area recently by each of the Arctic Seas. The question I asked myself was "how many days is each sea ice-free already?". I decided to use the criterion of ice area below 5% (sort-of) of recent years maxima, i.e. in effect a bit stricter than the 1 million km2 used for defining ice-free for the whole Arctic. I also used the NSIDC from their spreadsheet in their sea-ice-tools selection.

I attach three graphs - containing the peripheral seas, the seas composing the CAB, the peripheral seas,and Hudson Bay. Four peripheral seas are at or above 6 months ice-free. None others. Things only really started to happen in the CAB about 12 years ago. The Central Arctic Ocean and the Canadian Archipelago have yet to make an appearance on the graph. The Beaufort Sea made only one appearance - for 14 days in 2012.

A long way to go for an ice-free Arctic even for a day ?

If I am still extant, it will be interesting to see how this changes over the years.

Title: Re: Ice-free Arctic
Post by: Daniel B. on April 13, 2018, 05:06:54 PM
Nice work gerontocrat.
Title: Re: Ice-free Arctic
Post by: oren on April 14, 2018, 12:04:13 AM
I've been looking at area recently by each of the Arctic Seas. The question I asked myself was "how many days is each sea ice-free already?". I decided to use the criterion of ice area below 5% (sort-of) of recent years maxima, i.e. in effect a bit stricter than the 1 million km2 used for defining ice-free for the whole Arctic. I also used the NSIDC from their spreadsheet in their sea-ice-tools selection.
Very good. I think the results are quite significant, with 2007 being the point where the ongoing changes made themselves apparent.
May I suggest using other criteria as well, besides the 5%. The reasoning behind this is that some of these seas have become seasonally ice free in parts of their geography, while other parts of the same seas are still ice-covered throughout the year. So using thresholds of 15%, and even 50%, could yield interesting results.
Title: Re: Ice-free Arctic
Post by: litesong on April 16, 2018, 04:52:05 PM
<snip, enough already, this is getting repetitive; N.>
Title: Re: Ice-free Arctic
Post by: El Cid on April 16, 2018, 05:38:25 PM
<snip; N.>

This is really mean. Name-calling is for weaklings anyway. Just because someone's views do not coincide with your views does not make him an AGW denier. Mind you, the current scientific consensus puts an ice free arctic somewhere between 2040-2100 depending on who you believe. So, you probably have to live quite long to see an ice-free arctic IF you believe scientists. However, if you believe that you know better than scientists than of course anything is possibble.

I do not hink that anyone on this forum is an AGW denier. Still, as there are numerous debates about feedbacks, changes to atmospheric circulation, etc, etc, there can be many equally valid views about arctic ice. The greatest scientists are those who doubt even their own results, and keep questioning their own views all the time. Beware those who have no doubts about their own truth...
Title: Re: Ice-free Arctic
Post by: gerontocrat on April 16, 2018, 08:06:56 PM
"AGW denier daniel"

I also have doubts as to whether the Arctic will ever be entirely ice-free all year round (this century at least) unless all efforts to reduce CO2 emissions and the resulting increased CO2 ppm are entirely fruitless.

I would be fascinated to see how this makes me "AGW denier gerontocrat ", preferably in a series of logical steps from -

a) Doubts about a year long ice-free  Arctic,
to:
b) denial of AGW.

Waiting breathlessly.....
Title: Re: Ice-free Arctic
Post by: Shared Humanity on April 16, 2018, 09:40:32 PM
In the long polar night, ice will form. Put me in the camp of not believing that year long ice free will be occurring any time soon.
Title: Re: Ice-free Arctic
Post by: Alexander555 on April 16, 2018, 09:43:55 PM
And how would this planet look like if the arctic would be ice free all year long ?
Title: Re: Ice-free Arctic
Post by: Neven on April 16, 2018, 10:08:15 PM
Less white.  ;)
Title: Re: Ice-free Arctic
Post by: magnamentis on April 16, 2018, 10:10:16 PM
as we know the temperatures below which ice will form that would make winter temps of around -10C or higher to prevent ice building and even higher where rivers empty into the ocean.

so until we shall see such temperatures in winter i would rather think in centuries than decades, perhaps even millenia because that would make around 20-30C higher themps than we are currently reaching each winter. once ice is in place it will probably take even higher temps and waves to melt during winter time hence again, this is a long long time out.
Title: Re: Ice-free Arctic
Post by: Red on April 16, 2018, 10:39:08 PM
In the long polar night, ice will form. Put me in the camp of not believing that year long ice free will be occurring any time soon.

The nights are warming faster than the days!
Title: Re: Ice-free Arctic
Post by: Iceismylife on April 16, 2018, 11:17:29 PM
And how would this planet look like if the arctic would be ice free all year long ?
That is the big question. Neven's less white is telling. If the average night time low is -28C and ice free gets you 20 C warmer, and open sea water freezes at -10C Then you have a margin of 2C. Ice at the edges open in the middle.  Stormy enough to mix up the stratification in the Ocean. Overturning in the CAB.
Title: Re: Ice-free Arctic
Post by: oren on April 17, 2018, 02:47:47 AM
And how would this planet look like if the arctic would be ice free all year long ?
I find this discussion less interesting. An ice-free summer in the arctic is decades away, but an ice-free arctic in winter is at least centuries away, if at all.
Title: Re: Ice-free Arctic
Post by: Archimid on April 17, 2018, 03:40:40 AM
Less white.  ;)

Not if you ask bbr2314. ;D

And I'm starting to agree with him. As everyone agreed here, the atmosphere north of 60 will be below freezing in winter regardless of the amount of ice in the ocean. With all that extra water over an ice less Arctic and the extra global water vapor due to global warming it will probably snow at unimaginable levels in some places.

However I'm not at all convinced that snow will last the summer or restore the sea ice in time for another full melt. 
Title: Re: Ice-free Arctic
Post by: TerryM on April 17, 2018, 08:06:16 AM
Snow is also an amazingly effective insulator.
Will we have toasty ground and rocks getting warmer each summer as the severe winter cold kept at bay?
Terry
Title: Re: Ice-free Arctic
Post by: Pmt111500 on April 17, 2018, 12:32:28 PM
Could be fun exercise to try to calculate if the decreased albedo made by humans when the Arctic goes ice free in summer would be detectable from Alpha Centaurus using the kind of tech planned to send to space (James Webb Telescope, was it). Soon someone might take a note there's something going on on the planet system of the sixth star of the constellation Zigzag (Cassiopeia).
Title: Re: Ice-free Arctic
Post by: Gray-Wolf on April 17, 2018, 01:06:50 PM
The first few summers we see 'no ice' the opportunity for storms to drive deep overturning of the ocean stratification of the CAB will alter things making refreeze more difficult and very 'stop start' if storms constantly mix our the forming ice and bring up more warm, salty waters?

Late formed , thing ,salty ice will go faster the following summer and allow longer warming/overturning of the ocean.

I would also think we would see deep fog banks insulating the surface from the bitter cold Arctic night above?

During the PETM there must have been mechanisms for retaining heat all winter as we had palms there that need above 50f temps to survive ( along with the crocs!!).

Knowing it has existed, and existed with high temps not just marginal, must bring us pause for thought?
Title: Re: Ice-free Arctic
Post by: Pmt111500 on April 17, 2018, 02:55:27 PM

I would also think we would see deep fog banks insulating the surface from the bitter cold Arctic night above?


Yep, commonly seen here in autumn, essentially the same conditions that in lower latitudes produce 'wintry mix' (rain/snow). It takes a long time to ground to cool enough to this to stay on ground.

I'm not volunteering to any ships going to future winter Arctic, if you get clear weather it'll probably be one continuous freezing rain and splashes off the waves and if not you could be cleaning slush off the deck pretty much constantly. But of course I'm not entirely sure this will happen.
Title: Re: Ice-free Arctic
Post by: Forest Dweller on April 17, 2018, 06:57:56 PM
This has to be the most amusing topic i have read through so far  ;D
Lots of novice lurkers but also more qualified climate guys and it is interesting that way i think combined.
Let's not forget that many important scientific discoveries were made by total amateurs, some of which became great scientists.
As an urban wildlife researcher I find a lot of similarities.
"Novices, amateurs, citizens" or whatever one wants to call people often provide me with very good information and ideas while "experts" haven't a clue.

A smart researcher looks into every option/scenario however unlikely and works his/her butt off either proving or disproving.
You would be amazed at the stuff i find which is totally not what the status quo wants to hear.
You would be amazed at the amount of denial, corruption and information warfare which i won't bother you with.

I will mention McPherson too because the critique is mostly personal, not based on his essay which simply refers to other studies mostly.
I don't like him especially but he did a pretty good job of that and saying "think for yourself based on evidence".
He was not the first or the last, so irrelevant IMHO.

To topic;
Ice Free Arctic!
(We are all toast haha!!!)

Seriously guys....nobody knows.
Can we recocgnise the simple fact that we are in a unique situation?
Never happened before, comparisons to the big 5 extinctions of history etc...invalid.
A unique situation signifies the need for research.
It implores all of us to stop and learn.

When will the Arctic be free of ice?
Anytime....



Title: Re: Ice-free Arctic
Post by: Shared Humanity on April 17, 2018, 08:33:07 PM
Less white.  ;)

Not if you ask bbr2314. ;D

And I'm starting to agree with him. As everyone agreed here, the atmosphere north of 60 will be below freezing in winter regardless of the amount of ice in the ocean. With all that extra water over an ice less Arctic and the extra global water vapor due to global warming it will probably snow at unimaginable levels in some places.

However I'm not at all convinced that snow will last the summer or restore the sea ice in time for another full melt.

We are loading the atmosphere with energy and much of that energy is in the form of increased water vapor. Storms of all varieties will become much more intense. Anyone who has experienced a massive lake effect snow in Buffalo NY knows what this can look like. We are already seeing far more snowfall as a result of the open waters. I expect that we will begin to frequently see snowfall totals from a single storm that we have never seen before.

Just had over 2 feet of rain in Hawaii. Wait till we see the first 10 foot snowfall in say Scotland or Worchester, Massachusetts. People will die.

Not to mention sheep.

http://www.heraldscotland.com/news/13099609.10_000_lambs_and_ewes_estimated_dead_in_storms/
Title: Re: Ice-free Arctic
Post by: Daniel B. on April 17, 2018, 11:20:08 PM
Well said Forest,

Forecasts outside the realm of known outcomes are always quite speculative .  Whether current trends continue, increase, or decrease become increasing uncertain, the further away from established conditions.  We all have our guesses, based on which inputs we consider most important.  It is interesting and informative to hear other prognoses.  The Arctic could be ice free anytime, we just have little clue when that time will occur.
Title: Re: Ice-free Arctic
Post by: Coffee Drinker on April 18, 2018, 03:26:05 AM
I still think we underestimate the influence of volcanoes on our climate. They are completely unpredictable but can have massive impact on our climate.

A few VEI7 or an VEI8 and we can throw all our climate models into the garbage.

Overall, I think the impact of volcanoes on past climate is not very well researched and many unknowns remain.

Title: Re: Ice-free Arctic
Post by: crandles on April 18, 2018, 12:57:45 PM
I still think we underestimate the influence of volcanoes on our climate. They are completely unpredictable but can have massive impact on our climate.

A few VEI7 or an VEI8 and we can throw all our climate models into the garbage.

Overall, I think the impact of volcanoes on past climate is not very well researched and many unknowns remain.

Why? We can measure level of sulphates scattering sunlight effect pretty well. Yes they have large effect for 2 or 3 years but then the effects diminish pretty rapidly in line with the models. Effects have been forecasted and turned out to be pretty accurate.

So why do you think we are underestimating the influence?

(I am asking because your post looks like a denier attempt to cast doubt on our climate knowledge. So wondering if you will engage in discussion or if it is a drive by post.)
Title: Re: Ice-free Arctic
Post by: Coffee Drinker on April 18, 2018, 01:46:16 PM
I still think we underestimate the influence of volcanoes on our climate. They are completely unpredictable but can have massive impact on our climate.

A few VEI7 or an VEI8 and we can throw all our climate models into the garbage.

Overall, I think the impact of volcanoes on past climate is not very well researched and many unknowns remain.

Why? We can measure level of sulphates scattering sunlight effect pretty well. Yes they have large effect for 2 or 3 years but then the effects diminish pretty rapidly in line with the models. Effects have been forecasted and turned out to be pretty accurate.

So why do you think we are underestimating the influence?

(I am asking because your post looks like a denier attempt to cast doubt on our climate knowledge. So wondering if you will engage in discussion or if it is a drive by post.)

There are still lots of unknowns. Lots of "mays" and "perhaps". And the effects of volcanic activity "may" well exceed the often cited 2-3 years.

Just came across this study about Antarctic volcanic activity that may have anded glaciation in the southern hemisphere.
https://theconversation.com/two-centuries-of-continuous-volcanic-eruption-may-have-triggered-the-end-of-the-ice-age-83420

And now worries, my intention is not to cast doubt on climate knowledge. I just think its an interesting field of research that requires more attention. Every piece of the puzzle is important. And at the moment we are very far from a complete understanding.
Title: Re: Ice-free Arctic
Post by: Pmt111500 on April 18, 2018, 02:22:45 PM
Direct effect for larger eruption is likely the 2-3 years cited and by then it might have influence in some other metric that is better measured otherwise. No reason to exaggerate the influence. Anyway the ice core data gives pretty good constraints to the influence of smaller eruptions, there's though the season effect so f.e. an autumn small eruption might have larger influence than a spring time one, or the other way. I've used vei5 as a limit for limited global influence and the smaller ones would at most have effect hemispherically.
Title: Re: Ice-free Arctic
Post by: gerontocrat on April 18, 2018, 02:38:42 PM
Recently, a large number of volcanoes have been discovered under the Western Antractica. The theory is ( I think) that as the Antarctic ice sheet melts, pressure on the volcanoes will reduce, and volcanic activity will increase. But this is many years away even in Armageddon scenarios.

However, this is, apparently, a real possibility in Iceland. But, the effect on climate would be brief.
Title: Re: Ice-free Arctic
Post by: Ken Feldman on April 18, 2018, 07:08:08 PM
I still think we underestimate the influence of volcanoes on our climate. They are completely unpredictable but can have massive impact on our climate.

A few VEI7 or an VEI8 and we can throw all our climate models into the garbage.

Overall, I think the impact of volcanoes on past climate is not very well researched and many unknowns remain.

I'll agree with you that super large volcanic eruptions (VEI8) would have a very large impact on the climate and that we need to study them more.  Even large volcanic eruptions (VEI7) can have a long term (by human standards) effect on the climate.  It's now thought that increased volcanic activity in the 1300s and 1400s started the "little ice age".

And if there are a few VEI 8 eruptions, we won't be worrying about climate modeling, the few survivors on the globe will be too busy scrounging for food!  Fortunately, VEI 8 eruptions are very rare, happening about 30 million years apart.

Pinatubo was a VEI 5.  Krakatau was a VEI 6.  The Yellowstone eruptions were VEI 7, happening a few 100,000 years apart with the most recent about 650,000 years ago.

We have good measurements of the gases emitted by volcanoes and know that they are a small fraction of what humans emit.  Volcanoes emit between 180 million tons and 440 million tons of carbon dioxide per year, depending on the amount of volcanic activity.  Human emissions are on the order of 45 billion tons per year. 

In fact, we've increased the CO2 content of the atmosphere by almost 100 ppm since we started measuring it about 60 years ago, and the rate of increase is increasing to more than 20 ppm per decade.  We can see the effects of this right now and they are projected to get much worse before the end of this century.

So I think worrying about AGW and what we can do to reduce our emissions is a bit higher priority than worrying about the next VEI 7 eruption which is probably hundreds of thousands of years in the future.
Title: Re: Ice-free Arctic
Post by: rboyd on April 18, 2018, 08:00:51 PM
If we use CO2 equivalents, we are increasing the GHG load by about 35ppm per decade, with atmospheric methane continuing to increase due to shale gas. The true increase in radiative forcing is well above that, given the 20 year equivalent for methane, versus the 100 year number used by NOAA (as methane concentrations are increasing should we be using an even higher number for methane?).

https://www.esrl.noaa.gov/gmd/aggi/aggi.html (https://www.esrl.noaa.gov/gmd/aggi/aggi.html)

Given that temperatures have not fallen back as much as could previously be assumed post-Nino, we could be in for quite a temperature shock in the next decade. Less ice in the Arctic (and in the Antarctic?) will help drive the positive feedbacks.
Title: Re: Ice-free Arctic
Post by: gerontocrat on April 19, 2018, 01:43:49 PM
I blame Oren - I posted back on Friday April 13 and it was my bad luck he liked the graphs on ice-free days. In that post I just looked at the number of days with area less than 5% of average maxima for each sea. Oren suggested that I also use different percentages as well.

So the first posting looks at the peripheral seas. The graphs show the number of ice-free days from 1979 to 2017 where area is less than 5%, 15% and 50% of average maxima (sort of) in previous years.

I included 50% as this is more or less where we are in September extent compared with 1979.
Comments on individual seas below are ordered from the sea with the lowest ice-free days to the highest.

Greenland Sea
At 5% or less, apart from 2002 the answer is zero days.
At 15% or less, the result is patchy with no clear trend.
At 50% or less, a trend is visible, the number of days increasing from about 100 to about 150.
However, annual variations of export of ice down the Fram Strait presumably have quite an effect on sea ice area.

Barents Sea
The loss of sea ice area in the Barents sea is far greater.
At 5% or less, number of days increased from about 50 to well over 100,
At 15% or less, number of days increased from about 100 to approaching 200,
At 50% or less, number of days increased from about 150-200 to 300-350.

Baffin bay,Bering Sea, Okhotsk, St Lawrence
Variation is not high, though overall there are modest increases in days with less ice.
The Bering Sea data does show an upward spike in the last two or three years. (Perhaps 2018 is a continuation of that trend?)

Overall, there is an increase in ice-free days of about 50 days for each of the thre measures (5%, 15% and 50%). The peripheral seas (most vulnerable to sea ice melt) thus appear to show a consistent but gradual decline in area, suggesting a gradual move to an ice-free Arctic.
Title: Re: Ice-free Arctic
Post by: gerontocrat on April 19, 2018, 05:11:40 PM
I continue to blame Oren - I posted back on Friday April 13 and it was my bad luck he liked the graphs on ice-free days. In that post I just looked at the number of days with area less than 5% of average maxima for each sea. Oren suggested that I also use different percentages as well.

This second posting looks at the CAB seas (including Laptev and Kara). The graphs show the number of ice-free days from 1979 to 2017 where area is less than 5%, 15% and 50% of average maxima (sort of) in previous years.

The graphs do show the gradual advance of warming into the Kara, Chukchi, East-Siberian, and Laptev seas. Of note is that at no time is the extent in the Central Arctic or Canadian Archipelago at less than 50%. A similar set of graphs show the same result for Hudson Bay.

From 1979 to 2017 loss of sea ice area on any measure has been gradual. What is going to change that and when ?
Title: Re: Ice-free Arctic
Post by: oren on April 20, 2018, 10:34:42 AM
I blame Oren.
Great posts! Thank you so much gerontocrat. I blame myself as well, as I should have done the analysis myself instead of suggesting work for others... but your charts are much better looking than mine and the results more comprehensive.
In general I think the 50% charts are best at showing the trends for most seas.

Some commentary:
Quote
Greenland Sea
At 50% or less, a trend is visible, the number of days increasing from about 100 to about 150.
However, annual variations of export of ice down the Fram Strait presumably have quite an effect on sea ice area.
I didn't expect a trend for GS, but it seems the pre-melting of thin ice before it even reaches the Fram, and massive post-export melting in recent years while still in northerly waters, have caused this trend to materialize.

Quote
Barents Sea
The loss of sea ice area in the Barents sea is far greater.
At 5% or less, number of days increased from about 50 to well over 100,
At 15% or less, number of days increased from about 100 to approaching 200,
At 50% or less, number of days increased from about 150-200 to 300-350.
The Barents is one of the worst ground-zero locations for arctic change. The melting season has doubled in length, and about half of the Barents is now ice-free year-round (meaning of 365 days on the 50% chart). There was a major step change in 2006.

Quote
Baffin bay,Bering Sea, Okhotsk, St Lawrence
The Bering Sea data does show an upward spike in the last two or three years. (Perhaps 2018 is a continuation of that trend?)
Interesting. The Bering data might stand out more if the analysis was from Sep 1st to Sep 1st, as the 2017/2018 season had a very late refreeze and a very early melt.

Quote
The graphs do show the gradual advance of warming into the Kara, Chukchi, East-Siberian, and Laptev seas. Of note is that at no time is the extent in the Central Arctic or Canadian Archipelago at less than 50%. A similar set of graphs show the same result for Hudson Bay.
Chukchi - at least 50% of it has been seasonally ice-free historically, but now it's almost the whole sea (shown in the 5% chart). The 50% melting season has doubled in length from 75 to 150 days.
Kara - amazingly similar to the Chukchi in all measures.
ESS - its 5% and 15% charts separate the top years from all the rest. To be a record contender you must clear most of the ESS.
Beaufort - might show a clearer trend at 80% or 90%, if true will show that melt onset (+no more refreeze of opened cracks) is earlier, and perhaps refreeze completion is later.
CAA/CAB - should show a trend at 80% or 90%. I believe some parts of these regions have become seasonally ice-free, while other parts are still ice-covered year-round.
Interestingly, HB has a step change around 1995 in all the graphs, and has been stable since.

Quote
From 1979 to 2017 loss of sea ice area on any measure has been gradual. What is going to change that and when ?
I think the gradual assessment is true. But bear in mind, it's enough that the 5% chart consistently reaches 30 days in order to reach a seasonally ice-free state for each region. All external peripherals (plus Kara and Chukchi on most years) are already there. Laptev, Beaufort and ESS all made appearances on this chart, and when they line up we get an 2012.
The only regions that are still protected are the CAB and the CAA, and if they were split into sub-regions I think some of them would turn out to be seasonally ice-free as well. How long will these holdouts last? We'll be certain to tune in and find out.
Title: Re: Ice-free Arctic
Post by: jai mitchell on May 13, 2018, 06:31:36 PM
in the absence of northern hemisphere aerosol (air pollution) emissions we would see an ice free arctic within 2 years.

Title: Re: Ice-free Arctic
Post by: mitch on May 21, 2018, 07:14:40 PM
McKenzie River is moving along in its spring breakup--flowing water to the east edge of the delta, and some of the river water tunneling to the shelf fast ice.  We'll see how fast the river water spread out into the Beaufort Sea.