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5to10

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Re: Ice-free Arctic
« Reply #100 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.

Archimid

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Re: Ice-free Arctic
« Reply #101 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.
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Archimid

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Re: Ice-free Arctic
« Reply #102 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.
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Tor Bejnar

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Re: Ice-free Arctic
« Reply #103 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.)

Arctic ice is healthy for children and other living things.

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Re: Ice-free Arctic
« Reply #104 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.
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Archimid

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Re: Ice-free Arctic
« Reply #105 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


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.
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gerontocrat

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Re: Ice-free Arctic
« Reply #106 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).

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oren

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Re: Ice-free Arctic
« Reply #107 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

Tor Bejnar

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Re: Ice-free Arctic
« Reply #108 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
...
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
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 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.)
« Last Edit: February 25, 2017, 02:57:50 AM by Tor Bejnar »
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wili

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Re: Ice-free Arctic
« Reply #109 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
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Re: Ice-free Arctic
« Reply #110 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.

TerryM

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Re: Ice-free Arctic
« Reply #111 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

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Re: Ice-free Arctic
« Reply #112 on: February 25, 2017, 02:56:00 AM »
Archimid found it (see above - published in 2011).  But thanks.
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Re: Ice-free Arctic
« Reply #113 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


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


Tor Bejnar

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Re: Ice-free Arctic
« Reply #114 on: February 25, 2017, 02:53:18 PM »
Thanks, Terry!

Impact of instantaneous sea ice removal in a coupled general circulation model
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. ...
Arctic ice is healthy for children and other living things.

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Re: Ice-free Arctic
« Reply #115 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

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).

Shared Humanity

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Re: Ice-free Arctic
« Reply #116 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.
« Last Edit: February 25, 2017, 10:01:01 PM by Shared Humanity »

Archimid

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Re: Ice-free Arctic
« Reply #117 on: February 26, 2017, 02:52:54 AM »
Thanks, Terry!

Impact of instantaneous sea ice removal in a coupled general circulation model
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.


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Glenn Tamblyn

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Re: Ice-free Arctic
« Reply #118 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.

5to10

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Re: Ice-free Arctic
« Reply #119 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.

magnamentis

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Re: Ice-free Arctic
« Reply #120 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
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5to10

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Re: Ice-free Arctic
« Reply #121 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.

TerryM

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Re: Ice-free Arctic
« Reply #122 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

magnamentis

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Re: Ice-free Arctic
« Reply #123 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
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oren

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Re: Ice-free Arctic
« Reply #124 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.

TerryM

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Re: Ice-free Arctic
« Reply #125 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

magnamentis

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Re: Ice-free Arctic
« Reply #126 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.
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Ken Feldman

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Re: Ice-free Arctic
« Reply #127 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


Archimid

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Re: Ice-free Arctic
« Reply #128 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.

I am an energy reservoir seemingly intent on lowering entropy for self preservation.

Ken Feldman

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Re: Ice-free Arctic
« Reply #129 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

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.

Archimid

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Re: Ice-free Arctic
« Reply #130 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.

I am an energy reservoir seemingly intent on lowering entropy for self preservation.

liefde

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Re: Ice-free Arctic
« Reply #131 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

liefde

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Re: Ice-free Arctic
« Reply #132 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..

liefde

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Re: Ice-free Arctic
« Reply #133 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.

Archimid

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Re: Ice-free Arctic
« Reply #134 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.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

Gray-Wolf

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Re: Ice-free Arctic
« Reply #135 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?)?
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Daniel B.

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Re: Ice-free Arctic
« Reply #136 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.

Andreas T

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Re: Ice-free Arctic
« Reply #137 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.

Gray-Wolf

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Re: Ice-free Arctic
« Reply #138 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?
KOYAANISQATSI

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Gray-Wolf

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Re: Ice-free Arctic
« Reply #139 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!
KOYAANISQATSI

ko.yaa.nis.katsi (from the Hopi language), n. 1. crazy life. 2. life in turmoil. 3. life disintegrating. 4. life out of balance. 5. a state of life that calls for another way of living.
 
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Ken Feldman

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Re: Ice-free Arctic
« Reply #140 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.

Ken Feldman

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Re: Ice-free Arctic
« Reply #141 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  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.

Alexander555

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Re: Ice-free Arctic
« Reply #142 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.

Archimid

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Re: Ice-free Arctic
« Reply #143 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.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

Archimid

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Re: Ice-free Arctic
« Reply #144 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.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

Gray-Wolf

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Re: Ice-free Arctic
« Reply #145 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.
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gerontocrat

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Re: Ice-free Arctic
« Reply #146 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.

« Last Edit: March 09, 2018, 03:27:20 PM by gerontocrat »
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Archimid

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Re: Ice-free Arctic
« Reply #147 on: March 09, 2018, 03:10:31 PM »


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.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

oren

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Re: Ice-free Arctic
« Reply #148 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.

gerontocrat

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Re: Ice-free Arctic
« Reply #149 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)



"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)