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When will the Arctic Extent dip below 1,000,000 Km^2

2018-2019
12 (17.9%)
2020-2025
21 (31.3%)
2026-2030
13 (19.4%)
2031-2040
15 (22.4%)
2041-2060
2 (3%)
2061-2080
0 (0%)
2081-2099
1 (1.5%)
2100-beyond
3 (4.5%)

Total Members Voted: 66

Voting closed: July 27, 2018, 07:46:32 AM

Author Topic: When will the Arctic Go Ice Free?  (Read 17252 times)

gerontocrat

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Re: When will the Arctic Go Ice Free?
« Reply #50 on: July 30, 2018, 07:59:19 PM »

Someone also mentioned the possibility that a destruction of "BAU", which I take to mean a major societal disruption, could stop the melt. That may be possible, but I'm skeptical of that. Even if that does occur, I remember this quote from the 2017 CSSR (https://science2017.globalchange.gov/chapter/executive-summary/):

Quote
over the next few decades (2021–2050), annual average temperatures are expected to rise by about 2.5°F for the United States, relative to the recent past (average from 19762005), under all plausible future climate scenarios


"all plausible future climate scenarios". Now that needs thinking about. The world's future according to the decision-makers is built on a world economic growth assumption of 3 to 4 percent per annum growth. Future climate scenarios have this built in specifically (IPCC system) or even subconsciously by climate and other scientists in general. It is impossible to even suggest the possibility that this is hogwash without being labelled a doomsday nut. But this assumption is only a post WWII phenomenon as regards the world. China only got on the track in the early 1980's, India and many other Asian countries even later.

Look at the threads on forests, soil degradation, world ocean desertification (fish stocks), insect and other wildlife decline, water resources problems. I believe that severe economic disruption is a real possibility sometime not so far in the future. CO2 emissions did decline a bit in the financial crash of 2008 and its aftermath, and might decline much more in an era of world economic contraction.

My view is that there is a plausible future climate scenario where there is a significant change in humans impact on climate - we are in the anthropocene age, after all.

But that is likely to be after the first few instances of a BOE.

This time I really, really mean it - as Forrest Gump said - "And that's all I'm going to say about that".
"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)

bluesky

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Re: When will the Arctic Go Ice Free?
« Reply #51 on: July 30, 2018, 08:02:55 PM »
The arctic going ice couldn't possibly have less to do with the Paris deal.  The warming we are feeling now is mostly from GHG emissions from decades ago. GHGs are like a lid on a pot; as the lid gets thicker the stuff in the pot gets warmer, but it takes some time...in this case probably 20-30 years. The warming we have seen so far is primarily from emissions up to 1990, so about 350 ppm.

There is also a serious lag due to ice melting. Stable climate conditions that would lead to zero ice wouldn't result in the change occurring in a single year. It would likely take at minimum a decade.  Our current GHG levels are plenty high for an ice free arctic (ocean), but we are in the lag phase.

Of course, we haven't stabilized GHG levels, and plans like the Paris deal only scratch the surface of the necessary solutions.  Unfortunately even people who do pay attention to the climate situation are somehow soothed into believing that if only we adopt Paris and then maybe a little more, we will avoid the worst. 

It is madness. Worse than pure denial of the entire situation. I'm less bothered by those who think it is all an elite globalist ploy to enslave the masses, than I am by those who engage with the data on a daily basis but come to the conclusion that mild solutions will be sufficient to save civilization.  OR for that matter those who think that it is no big deal to change the climate drastically and kill off humanity cuz the earth will bounce back.  Are we really going to successfully prevent nuclear war as everything falls apart? Are we really going to successfully decommission the hundreds of nuclear power plants around the world? Even if you aren't bothered by the collapse of civilization and the horrible deaths of billions of people, the possibility of turning the earth into a planet like venus or mars should give you some pause.

The only genuine solution would be for the entire world to embark on creating a global carbon-negative permaculture landscape. Global knowledge sharing could continue but global trade would be reduced to maybe 1% its current volume.  Ironically, everyone would be happier and healthier, but this is not an option...lets just adopt Paris, pat ourselves on the back, and when it all starts to burn blame somebody else.

Agree with the fact that there is long hysteresis in global warming, i.e. we are still experiencing the consequence of 300 to 350 ppm of CO2, and agree with most of the remaining.
There have been a few research paper confirming that even if we would stop any greenhouse gas emission from today the Arctic sea ice would still continue to melt; The well publicised 2012 paper on El’gygytgyn lake temperature in North East Siberia, testimony that in the early Pleistocene the CO2 level was close to today 's level (so we need to go back almost 3 million years ago to find a similarly very high level of CO2) and the temperature in the Artic was approximately 8°C warmer than today, although the orbital (Milankovitch) cycle forcings were likely different. Also the most recent paper "Palaeoclimate constraints on the impact of 2° C anthropogenic warming and beyond" H Fischer et al, they state that the impact of a 1 to 2°C warming, so were we are in the moment including the hysteresis impact in the pipeline, lead to several centuries of substantial melting of Greenland and Antarctic ice sheet:

Abstract:
"Over the past 3.5 million years, there have been several intervals when climate conditions were warmer than during the preindustrial Holocene. Although past intervals of warming were forced differently than future anthropogenic change, such periods can provide insights into potential future climate impacts and ecosystem feedbacks, especially over centennial-to-millennial timescales that are often not covered by climate model simulations. Our observation-based synthesis of the understanding of past intervals with temperatures within the range of projected future warming suggests that there is a low risk of runaway greenhouse gas feedbacks for global warming of no more than 2 °C. However, substantial regional environmental impacts can
occur. A global average warming of 1–2 °C with strong polar amplification has, in the past, been accompanied by significant shifts in climate zones and the spatial distribution of land and ocean ecosystems. Sustained warming at this level has also led to substantial reductions of the Greenland and Antarctic ice sheets, with sea-level increases of at least several metres on millennial timescales. Comparison of palaeo observations with climate model results suggests that, due to the lack of certain feedback processes, model-based climate projections may underestimate long-term warming in response to future radiative forcing by as much as a factor of two, and thus may also underestimate centennial-to-millennial-scale sea-level rise."
http://eprints.esc.cam.ac.uk/4301/2/41561_2018_146_MOESM1_ESM.pdf



« Last Edit: July 30, 2018, 08:09:50 PM by bluesky »

Ned W

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Re: When will the Arctic Go Ice Free?
« Reply #52 on: July 30, 2018, 08:36:03 PM »
There certainly is a lot of doom and gloom around here, as usual.  I'll dissent from that, with some predictions that don't involve the near-future collapse of civilization:

1. The first year with a sub-1 million km ice extent day will probably occur in the late 2020s or 2030s. 

2. Insofar as the past 40 years' reduction in September ice extent has induced some fairly subtle changes in northern hemisphere climate during the fall months, those changes will continue and get bigger as the ice extent at minimum shrinks, but there won't be any sudden game-changing effect from crossing the purely arbitrary 1,000,000 km2 threshold.

3. Subsequent years will bounce back (as 2013 did after the 2012 low) but extreme low-ice (under 1,000,000 km2) years will become more and more common until they are the rule, rather than the exception, probably by 2040 or so. 

4. The duration of that annual very-low-ice-extent period will expand during the second half of the century to produce first ice-free Septembers, then ice-free summers.  There won't be an ice-free year in this century, and probably not in the next, either.

5. There won't be any 50-GT "methane bomb".   There was none in the early Holocene when the Arctic Ocean was ice-free during summers.  There was none during the previous interglacial (MIS 5e), when the Arctic was quite warm.  There was none during interglacial MIS-11, when the Arctic was so warm for so long that virtually all the land ice in Greenland melted. 

6. An ice-free Arctic Ocean won't lead to the collapse of civilization. The Arctic is already halfway ice-free in September now, and the effects of that are not particularly civilization-imperiling.


bluesky

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Re: When will the Arctic Go Ice Free?
« Reply #53 on: July 30, 2018, 08:40:19 PM »
too late for the poll but would have hesitated between 2020-25 and 2026-30, even if it is later than the less optimistic, the situation is extremely dire as in the meantime Asia and Africa would have substantially increase its greenhouse gases emission leading to further hysteresis in the climate warming; while Europe, Japan and US would  have barely decreased theirs unless electrical cars replace combustion engine very quickly and everybody decide to equip his house/comdo  estate roof with solar panels, but I doubt it will happen seriously before 2030 - 2040, and not sure some lobbying energy conglomerate will allow massive equipment of solar panel (it will be their demise), besides, battery production might still be non environmental friendly…the issue of low cost air travel will still be around, electric lorries will take time to take off, together with freight boats, while permafrost could start to melt seriously after summer blue arctic event leading to uncontrollable warming (together with other numerous tipping point) … it could be that the hinderance from energy companies may lead to a carbone emitting production of electrical energy… We need a grassroot change, each of us should try to convince a couple of friends around us who do not know anything about climate change, and that they in turn convince a couple of friends. If 25% of the world population decide to change their way of life within the next couple of years, that could be the beginning of a  positive social awareness, a positive citizen tipping point… then it could spread massively

Steven

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Re: When will the Arctic Go Ice Free?
« Reply #54 on: July 30, 2018, 08:56:48 PM »
This applies to every seasonal ice zone in the world, and yet (to give but one example) Hudson Bay refreezes every winter.
Well, the Hudson doesn't have a major warm ocean current flowing into it - it is well inland (which means it has a continental climate with cold winters and warm summers) and the nearest warm ocean currents are very far away.

Laptev Sea is another example.  It is seasonally ice free, but it refreezes completely every year in October, even after strong melt seasons.  An interesting feature about Laptev Sea is that the ice edge in October usually expands from two directions: from the north (Central Arctic) as well as from the south (Siberian coast):





The freeze-up date in Laptev Sea has a long term trend of about 5 days per decade (see table below from Stroeve et al 2014).  Clearly it's still a long way from perennially ice-free.




bluesky

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Re: When will the Arctic Go Ice Free?
« Reply #55 on: July 30, 2018, 09:04:11 PM »
There certainly is a lot of doom and gloom around here, as usual.  I'll dissent from that, with some predictions that don't involve the near-future collapse of civilization:

1. The first year with a sub-1 million km ice extent day will probably occur in the late 2020s or 2030s. 

2. Insofar as the past 40 years' reduction in September ice extent has induced some fairly subtle changes in northern hemisphere climate during the fall months, those changes will continue and get bigger as the ice extent at minimum shrinks, but there won't be any sudden game-changing effect from crossing the purely arbitrary 1,000,000 km2 threshold.

3. Subsequent years will bounce back (as 2013 did after the 2012 low) but extreme low-ice (under 1,000,000 km2) years will become more and more common until they are the rule, rather than the exception, probably by 2040 or so. 

4. The duration of that annual very-low-ice-extent period will expand during the second half of the century to produce first ice-free Septembers, then ice-free summers.  There won't be an ice-free year in this century, and probably not in the next, either.

5. There won't be any 50-GT "methane bomb".   There was none in the early Holocene when the Arctic Ocean was ice-free during summers.  There was none during the previous interglacial (MIS 5e), when the Arctic was quite warm.  There was none during interglacial MIS-11, when the Arctic was so warm for so long that virtually all the land ice in Greenland melted. 

6. An ice-free Arctic Ocean won't lead to the collapse of civilization. The Arctic is already halfway ice-free in September now, and the effects of that are not particularly civilization-imperiling.

1 Human kind is pushing the process in a way that the world has never experienced before. There is no scientific paper showing any time in paleoclimate when the greenhouse gases have increased so quickly. As James Hansen often say, we are doing a unique experiment at an extremely high speed

"Global mean atmospheric carbon dioxide (CO2) concentration has now passed 400 ppm, a level that last occurred about 3 million years ago, when global average temperature and sea level were significantly higher than today (high confidence). Continued growth in CO2 emissions over this century and beyond would lead to an atmospheric concentration not experienced in tens of millions of years (medium confidence). The present-day emissions rate of nearly 10 GtC per year suggests that there is no climate analog for this century any time in at least the last 50 million years (medium confidence)."
https://science2017.globalchange.gov/chapter/4/


And I think we are now in the process of tipping 410 ppm

2 therefore modelling the tipping points and when and how they are going to happen is dangerously uncertain

3 climate change is coming on top of other major environmental impacts very well described by Elizabeth Kolbert in the 6th extinction published in 2015

4 the tipping points are numerous (see below, and the Postdam Institut website) , and some are "modelled" (with high uncertainty) to be triggered at 2.5°c (e.g. the end of carbone sink role from the rain forest in the amazon... ocean acidification...) this could almost already be in the pipeline due to climate change hysteresis and the evident BAU path that we are continuing

5 There is a risk of multiple or sequential/cascading  tipping points could happen  in close sequences, this was pinpointed in the US climate assessment (chapter 15) to the US congress at the end of last year

6 As an exemple, the synchronicity of blue ocean Arctic sea triggering a much faster Greenland ice sheet melting and rapid permafrost melting increasing further greenhouse gases, with a potential rapid collapse of West Antartic ice sheet, is not to excluded post 2050. While simultaneous collapse of Amazon rain forest and ocean carbon sink is not to be excluded...

Tipping points:


(even if I don't necessarily agree with all the interpretation from Paul Beckwith particularly SRM solar radiation management -probably not feasable-, this somewhat  tie with the great uncertainty pinpoint the US climate report)


https://www.pik-potsdam.de/services/infodesk/tipping-elements


« Last Edit: July 30, 2018, 09:29:56 PM by bluesky »

sinocentric

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Re: When will the Arctic Go Ice Free?
« Reply #56 on: July 30, 2018, 09:24:04 PM »

Look at the threads on forests, soil degradation, world ocean desertification (fish stocks), insect and other wildlife decline, water resources problems. I believe that severe economic disruption is a real possibility sometime not so far in the future. CO2 emissions did decline a bit in the financial crash of 2008 and its aftermath, and might decline much more in an era of world economic contraction.

Just to be clear, I agree this is a possibility. I don't think the future is looking very bright for the world economy. However, from the CSSR again (https://science2017.globalchange.gov/chapter/4/):

Quote
Even if existing concentrations could be immediately stabilized, temperature would continue to increase by an estimated 1.1°F (0.6°C) over this century, relative to 1980–1999.

Correct me if I'm wrong, but that seems to indicate that temperatures will continue to increase throughout the century even if we stop emissions. And we're already over 400 ppm. My guess is that we have enough C02 in the atmosphere to get an ice free day in the arctic, even if civilization collapsed totally tomorrow.

gerontocrat

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Re: When will the Arctic Go Ice Free?
« Reply #57 on: July 30, 2018, 09:38:14 PM »

Quote
Even if existing concentrations could be immediately stabilized, temperature would continue to increase by an estimated 1.1°F (0.6°C) over this century, relative to 1980–1999.

Correct me if I'm wrong, but that seems to indicate that temperatures will continue to increase throughout the century even if we stop emissions. And we're already over 400 ppm. My guess is that we have enough C02 in the atmosphere to get an ice free day in the arctic, even if civilization collapsed totally tomorrow.

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magnamentis

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Re: When will the Arctic Go Ice Free?
« Reply #58 on: July 30, 2018, 09:53:09 PM »
There certainly is a lot of doom and gloom around here, as usual.  I'll dissent from that, with some predictions that don't involve the near-future collapse of civilization:

1. The first year with a sub-1 million km ice extent day will probably occur in the late 2020s or 2030s. 

2. Insofar as the past 40 years' reduction in September ice extent has induced some fairly subtle changes in northern hemisphere climate during the fall months, those changes will continue and get bigger as the ice extent at minimum shrinks, but there won't be any sudden game-changing effect from crossing the purely arbitrary 1,000,000 km2 threshold.

3. Subsequent years will bounce back (as 2013 did after the 2012 low) but extreme low-ice (under 1,000,000 km2) years will become more and more common until they are the rule, rather than the exception, probably by 2040 or so. 

4. The duration of that annual very-low-ice-extent period will expand during the second half of the century to produce first ice-free Septembers, then ice-free summers.  There won't be an ice-free year in this century, and probably not in the next, either.

5. There won't be any 50-GT "methane bomb".   There was none in the early Holocene when the Arctic Ocean was ice-free during summers.  There was none during the previous interglacial (MIS 5e), when the Arctic was quite warm.  There was none during interglacial MIS-11, when the Arctic was so warm for so long that virtually all the land ice in Greenland melted. 

6. An ice-free Arctic Ocean won't lead to the collapse of civilization. The Arctic is already halfway ice-free in September now, and the effects of that are not particularly civilization-imperiling.

i'm generally with you but here we go with the arbitrary and man-made threshold of 1M km2

it's exactly as big of a problem as i always thought and future will prove.

you say there will be no sudden game change once reaching less than 1M km2 extent, you're right, which is why i say only close or quasi zero extent will cause that game change.

once there will be no ice left in mid-summer and exactly that year, once of a sudden, temps in the arctic will be driven up from the current 0C +/- a few to something like 10, 15 and perhaps even peaking at 20C and THAT my dear friends WILL BE a sudden change and have a huge impact on the following winters and the entire NH and later global.

all this is totally logical and the entire discussion about effects, scale as well as speed, could be almost entirely saved or at least reduced to the important parts once we would stop inventing arbitrary thresholds just to satisfy our lust for sensation (headlines)

the year the news will call it an ice-free arctic while we shall see 999999km2 of ice by naked eyes from above i'll lough out loudly.

IMO this 1M km2 thingy is ridiculous at best and very damaging most probably. that threshold will pass without major impact and after doomsday news abate people will say, you see, nothing happens and again we shall have to fight for awareness for something that WILL happen but
our impatience and the eagerness to call it as early as possible will spoil the effect and once
the day will come mankind will not be ready AGAIN and unfortunately it will be those who
do not have much capabilites left (timewise, moneywise, educationwise etc.) to make a change
and those who had it preferred to discuss in who is right and superlatives way.
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miki

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Re: When will the Arctic Go Ice Free?
« Reply #59 on: July 30, 2018, 10:14:48 PM »
There certainly is a lot of doom and gloom around here, as usual.  I'll dissent from that, with some predictions that don't involve the near-future collapse of civilization:

1. The first year with a sub-1 million km ice extent day will probably occur in the late 2020s or 2030s. 

2. Insofar as the past 40 years' reduction in September ice extent has induced some fairly subtle changes in northern hemisphere climate during the fall months, those changes will continue and get bigger as the ice extent at minimum shrinks, but there won't be any sudden game-changing effect from crossing the purely arbitrary 1,000,000 km2 threshold.

3. Subsequent years will bounce back (as 2013 did after the 2012 low) but extreme low-ice (under 1,000,000 km2) years will become more and more common until they are the rule, rather than the exception, probably by 2040 or so. 

4. The duration of that annual very-low-ice-extent period will expand during the second half of the century to produce first ice-free Septembers, then ice-free summers.  There won't be an ice-free year in this century, and probably not in the next, either.

5. There won't be any 50-GT "methane bomb".   There was none in the early Holocene when the Arctic Ocean was ice-free during summers.  There was none during the previous interglacial (MIS 5e), when the Arctic was quite warm.  There was none during interglacial MIS-11, when the Arctic was so warm for so long that virtually all the land ice in Greenland melted. 

6. An ice-free Arctic Ocean won't lead to the collapse of civilization. The Arctic is already halfway ice-free in September now, and the effects of that are not particularly civilization-imperiling.

I'm basically ok with the above, but only if the global temperature anomalies stay as they are, and, possibly, if the rate of arctic and global warming "miraculously" inverts drastically its current course.

Otherwise, I do not see how the ice, on sea and on land, would make it past the end of the next century.
« Last Edit: July 30, 2018, 10:20:36 PM by miki »

gerontocrat

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Re: When will the Arctic Go Ice Free?
« Reply #60 on: July 30, 2018, 10:17:11 PM »
There certainly is a lot of doom and gloom around here, as usual.  I'll dissent from that, with some predictions that don't involve the near-future collapse of civilization:

1. The first year with a sub-1 million km ice extent day will probably occur in the late 2020s or 2030s. 

5. There won't be any 50-GT "methane bomb".   There was none in the early Holocene when the Arctic Ocean was ice-free during summers.  There was none during the previous interglacial (MIS 5e), when the Arctic was quite warm.  There was none during interglacial MIS-11, when the Arctic was so warm for so long that virtually all the land ice in Greenland melted. 

6. An ice-free Arctic Ocean won't lead to the collapse of civilization. The Arctic is already halfway ice-free in September now, and the effects of that are not particularly civilization-imperiling.

1. I am going for mid 2020's based on PIOMAS volume trend plus a bit of a crash when the ice just gets too thin.

5. Methane Bombs ? probably not. Accelerated methane release ? A real possibility. Lots of posts on the methane thread in permafrost board from a few months ago - some real science there from Russian scientists based on field research.

6. An ice-free Arctic Ocean won't lead to the collapse of civilization. Who said it did ? (Not guilty, quoth I). I agree, but there is lots of other stuff going on where climate change is just making bad things being done by humans worse.
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Stephan

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Re: When will the Arctic Go Ice Free?
« Reply #61 on: July 30, 2018, 10:17:21 PM »
When I understood Prof Beckwith correctly, the BOE does not stand for zero but for "less than a million" km² of sea ice. I do not know how scientists came to that number.
The problem is the coastal zone of Greenland. If you follow Espen's wonderful threads on individual glaciers you can see a lot of bays and fjords on almost all the eastern, northern and NW coast into which many glaciers flow. Many of these glaciers end up in these bays and fjords which seem to be almost all-year-round covered by fast ice. This is probably thicker and much more resilient towards melt than "usual" sea ice and its movement is blocked by islands, ice rises or other obstacles. Therefore they can not flow away as "usual" sea ice is able to. And the glaciers are permamently calving, adding new ice into these places.
The second point is the northern shore of Ellesmere island. Currents push ice towards this coast and even if most of the sea ice is gone remains will keep stuck there.
I have no idea how many km² of these bays and fjords will be still ice-covered even if the "usual" sea ice is gone (apart from the Ellesmere island). But it will be much more than only some thousand km². Climate deniers will - of course - point their fingers into this direction and blame us to publish another fake news.

The problem is - if BOE once happens it WILL change the weather, the currents and have an impact on the next freezing season. And it WILL then be too late for humanity to change their behaviour, their consumption, their energy needs etc. Probably it is already too late...
« Last Edit: July 30, 2018, 10:30:21 PM by Stephan »

gerontocrat

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Re: When will the Arctic Go Ice Free?
« Reply #62 on: July 30, 2018, 10:33:19 PM »

The problem is the coastal zone of Greenland. If you follow Espen's wonderful threads on individual glaciers you can see a lot of bays and fjords on almost all the eastern, northern and NW coast into which many glaciers flow. Many of these glaciers end up in these bays and fjords which seem to be almost all-year-round covered by fast ice. This is probably thicker and much more resilient towards melt than "usual" sea ice and its movement is blocked by islands, ice rises or other obstacles. Therefore they can not flow away as "usual" sea ice is able to. And the glaciers are permanently calving, adding new ice into these places.


Greenland is surrounded by the Baffin, Greenland and Canadian Archipelago seas. The 2010's average total minimum extent for these 3 seas is under 0.6 million km2.  The fjords and bays on the Greenland coast are a small fraction of that, and sea ice data excludes the glaciers (not being sea ice).

The 1 million km2 figure is, I suspect designed to stop deniers looking to remaining odd bits of ice to deny a BOE. By then I think even the Koch brothers will have stopped financing climate denier organisations (they don't like wasting money).
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Wherestheice

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Re: When will the Arctic Go Ice Free?
« Reply #63 on: July 30, 2018, 10:39:13 PM »
When the ice is where it’s At now or even in 2012, there is still enough ice to absorb most of the solar radiation, when that’s all gone where does the radiation go?? Into the twilight zone maybe?? No it goes into the ocean. Once that happens everything won’t be ok. What happens in the arctic doesn’t stay in the arctic. Our civilization is really close to collapsing. We’ve lost so much of the natural world, and yet we continue. The whole world is in debt, things are getting worse( if you can’t see that, than open your eyes). When that ice goes away enough for the solar radiation to be focused on the ocean, I think that’s gonna do it. I will admit that I could be wrong (and hope to be wrong btw), earth is a very unpredictable system. You just can’t keep shitting on your nest and not expect bad stuff to happen. Idk when the collapse of civilization will happen, but it looks to be sooner than later. Humans are an animal and yes it’s possible for us to go extinct, idk why people think we’re so special. We have smart brains, and 5 fingers, but we aren’t invincible. There is obviously a clear divide in opinion on this forum. I respect everyone’s views and thoughts because I believe that’s how science is truly learned.
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GoSouthYoungins

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Re: When will the Arctic Go Ice Free?
« Reply #64 on: July 30, 2018, 10:43:28 PM »
There certainly is a lot of doom and gloom around here, as usual.  I'll dissent from that, with some predictions that don't involve the near-future collapse of civilization:

1. The first year with a sub-1 million km ice extent day will probably occur in the late 2020s or 2030s. 

2. Insofar as the past 40 years' reduction in September ice extent has induced some fairly subtle changes in northern hemisphere climate during the fall months, those changes will continue and get bigger as the ice extent at minimum shrinks, but there won't be any sudden game-changing effect from crossing the purely arbitrary 1,000,000 km2 threshold.

3. Subsequent years will bounce back (as 2013 did after the 2012 low) but extreme low-ice (under 1,000,000 km2) years will become more and more common until they are the rule, rather than the exception, probably by 2040 or so. 

4. The duration of that annual very-low-ice-extent period will expand during the second half of the century to produce first ice-free Septembers, then ice-free summers.  There won't be an ice-free year in this century, and probably not in the next, either.

5. There won't be any 50-GT "methane bomb".   There was none in the early Holocene when the Arctic Ocean was ice-free during summers.  There was none during the previous interglacial (MIS 5e), when the Arctic was quite warm.  There was none during interglacial MIS-11, when the Arctic was so warm for so long that virtually all the land ice in Greenland melted. 

6. An ice-free Arctic Ocean won't lead to the collapse of civilization. The Arctic is already halfway ice-free in September now, and the effects of that are not particularly civilization-imperiling.

It is not GLOOM and DOOM. It is only that way if people can't wrap their minds around the reality of the situation.

1. Rather optimistic. Ice could easily go sub 1 million in the next 5 years based on current trends in volume, Pacification related retreat, Atlantification related retreat, salinity encroachment, increased ocean temperature, increased atmospheric temperature, etc. The next serious El Nino will probably do the trick...just look at what is happening this year during neutral conditions.

2. Exponential function. The past 40 years of ice reduction in September are a result of GHG levels 20-40 years prior to that period. Which were hardly a deviation from historical trends. Since then we are 10 times further outside the semi-recent historical bounds. Obviously some random extent number threshold doesn't hold any real significance but that is totally moot in the larger context.

3. Ya, there will be some level variability. Again, so what? Totally moot. However, large scale melt and ocean mixing will be difficult to reverse.

4. WOW; 200 more years before the arctic could go ice free for the whole year. Yes, greenland may create a local effect which allows for some ice formation to its north for longer than the rest of the arctic but in general this idea is delusionally conservative. A simple extrapolation of current volume trends puts that timeline off by at least 150 years...without any lag and without any continued emission.

5. I agree. I think the giant methane burp idea is a little fanciful. I do think there will be a significant amount of methane released from permafrost that will cause short term and local effects which shouldn't be ignored.

6. An ice free arctic probably WILL lead to the collapse of civilization. As long as there is widespread ice in the arctic, the temperature stabilizer is in place. Once the arctic is a more typical ocean, this stabilizing dampener is gone, and the heat will kick into another year. Take a pistol with a trigger pull weight of 5 pounds. Pull it 3 pounds. Nothing happens. Are you comfortable putting the barrel in your mouth and doubling the pull force? Hyperbolic, yes. But reality is somewhere in between this and your extrapolation.  The north hemisphere will undergone almost unimaginable climate change once the ice mostly gone from the arctic. The northern ice cap will be drastically reduced and re-centered over greenland.  No computer can begin to accurately model the effects of a hemispheric cold center 15 degrees south of the pole. Russia will be the most severely and immediately effected, but the entire hemisphere where almost everyone happens to live will go into extreme climate chaos.
big time oops

josh-j

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Re: When will the Arctic Go Ice Free?
« Reply #65 on: July 30, 2018, 11:29:49 PM »
4. WOW; 200 more years before the arctic could go ice free for the whole year. Yes, greenland may create a local effect which allows for some ice formation to its north for longer than the rest of the arctic but in general this idea is delusionally conservative. A simple extrapolation of current volume trends puts that timeline off by at least 150 years...without any lag and without any continued emission.
(My bold)

I'm not sure that a simple extrapolation of the trend is necessarily correct when talking about a complex system. Various posters here have highlighted the "slow decline" theory in which the decline slows because more open ocean in summer means more space for ice to grow in winter.

Dharma Rupa

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Re: When will the Arctic Go Ice Free?
« Reply #66 on: July 30, 2018, 11:32:11 PM »
once there will be no ice left in mid-summer and exactly that year, once of a sudden, temps in the arctic will be driven up from the current 0C +/- a few to something like 10, 15 and perhaps even peaking at 20C and THAT my dear friends WILL BE a sudden change and have a huge impact on the following winters and the entire NH and later global.

When there is no longer enough ice to Keep DMI 80N pinned to near 0 in Summer everything will have changed, and all the this or that KM are meaningless.

My point is that we don't have any reason to believe the flip will happen in Summer.  At least one possibility is that the formation of ice in the Fall will suck up the last of the "fresh" water and release the warm water below.


GoSouthYoungins

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Re: When will the Arctic Go Ice Free?
« Reply #67 on: July 30, 2018, 11:50:39 PM »
4. WOW; 200 more years before the arctic could go ice free for the whole year. Yes, greenland may create a local effect which allows for some ice formation to its north for longer than the rest of the arctic but in general this idea is delusionally conservative. A simple extrapolation of current volume trends puts that timeline off by at least 150 years...without any lag and without any continued emission.
(My bold)

I'm not sure that a simple extrapolation of the trend is necessarily correct when talking about a complex system. Various posters here have highlighted the "slow decline" theory in which the decline slows because more open ocean in summer means more space for ice to grow in winter.

I agree, a simple extrapolation is way too basic. My point is that claiming something far outside the current trend requires strong supporting evidence. The slow decline theory has some serious merit but there are plenty of factors that work in the other direction: continued increased GHG forcing from lag and from continued emissions being the largest or at least most certain.
big time oops

magnamentis

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Re: When will the Arctic Go Ice Free?
« Reply #68 on: July 31, 2018, 03:14:37 AM »
once there will be no ice left in mid-summer and exactly that year, once of a sudden, temps in the arctic will be driven up from the current 0C +/- a few to something like 10, 15 and perhaps even peaking at 20C and THAT my dear friends WILL BE a sudden change and have a huge impact on the following winters and the entire NH and later global.

When there is no longer enough ice to Keep DMI 80N pinned to near 0 in Summer everything will have changed, and all the this or that KM are meaningless.

My point is that we don't have any reason to believe the flip will happen in Summer.  At least one possibility is that the formation of ice in the Fall will suck up the last of the "fresh" water and release the warm water below.

i understood that we have different views about what's possible but then just to point it out once, i very much appreciate your input because it would be foolish to not at least consider the apparently impossible. just wanted you to know that.

i disagree but with respect to your different views while we shall most probably hear (read) from each other, may it help to find the truth.

 ;)
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binntho

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Re: When will the Arctic Go Ice Free?
« Reply #69 on: July 31, 2018, 07:39:25 AM »
This applies to every seasonal ice zone in the world, and yet (to give but one example) Hudson Bay refreezes every winter.
Well, the Hudson doesn't have a major warm ocean current flowing into it - it is well inland (which means it has a continental climate with cold winters and warm summers) and the nearest warm ocean currents are very far away.

Laptev Sea is another example.  It is seasonally ice free, but it refreezes completely every year in October, even after strong melt seasons.  An interesting feature about Laptev Sea is that the ice edge in October usually expands from two directions: from the north (Central Arctic) as well as from the south (Siberian coast):

Again it's the difference that a warm ocean current, or absence of same, can make. The Laptev Sea is on similar latitudes to Svalbard and the surrounding ocean. One freezes solid each year, the other has had an almost totally ice-free winter. Both receive the same amount of insolation, but vastly different heat inputs from the oceans.

There have been some signs (more based on guesswork and satellite observations than direct measurements) that the warm tongue of the North Atlantic Current part of the Gulf Stream is creeping ever farther north, and perhaps to the east along the continental margin.

A scenario of year-round ice-free Arctic can only be reached (IMO) by further a northward reach of the warm ocean currents. Whether this is something that will happen, I've no idea. The Arctic has frozen every winter for the last 47 million years (according to a paper I read yesterday), and I guess it will take quite a lot to make it stop!

wili

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Re: When will the Arctic Go Ice Free?
« Reply #70 on: July 31, 2018, 08:16:36 AM »
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

liefde

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Re: When will the Arctic Go Ice Free?
« Reply #71 on: August 01, 2018, 12:09:54 AM »
warming we are feeling now is mostly from GHG emissions from decades ago. GHGs are like a lid on a pot; as the lid gets thicker the stuff in the pot gets warmer, but it takes some time...in this case probably 20-30 years. The warming we have seen so far is primarily from emissions up to 1990, so about 350 ppm.
Actually, no, that's not true; http://iopscience.iop.org/article/10.1088/1748-9326/9/12/124002;jsessionid=BC6F9B408139804AB3587C183EE22AAC.c1.iopscience.cld.iop.org

Maximum warming occurs a median of 10.1 years after the CO2 emission event and has a median value of 2.2 mK GtC−1.

Dharma Rupa

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Re: When will the Arctic Go Ice Free?
« Reply #72 on: August 01, 2018, 12:17:53 AM »
warming we are feeling now is mostly from GHG emissions from decades ago. GHGs are like a lid on a pot; as the lid gets thicker the stuff in the pot gets warmer, but it takes some time...in this case probably 20-30 years. The warming we have seen so far is primarily from emissions up to 1990, so about 350 ppm.
Actually, no, that's not true; http://iopscience.iop.org/article/10.1088/1748-9326/9/12/124002;jsessionid=BC6F9B408139804AB3587C183EE22AAC.c1.iopscience.cld.iop.org

Maximum warming occurs a median of 10.1 years after the CO2 emission event and has a median value of 2.2 mK GtC−1.
A quick glance says that is a model study.  Care to demonstrate any skill at all in the models?

liefde

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Re: When will the Arctic Go Ice Free?
« Reply #73 on: August 01, 2018, 12:32:40 AM »
A scenario of year-round ice-free Arctic can only be reached (IMO) by further a northward reach of the warm ocean currents.
I keep reading this dreamy misconception everywhere. People seem to be forgetting about the fact that the quantity of heat energy required to melt 1kg of ice (of just below freezing) to 1kg of water (of just above freezing) would raise the temperature of that same 1 kg of water to 80 degrees Celsius. This means that as soon as ice is gone, and there is heat energy (i.e. Sunlight), the oceans will be very hot at the surface (provided that surface T will also keep on rising as it does) all around the Arctic circle. It already is super anomalously warm, by the way. So when the sun is gone at the polar caps, all it needs is a little flow from warmer lower ocean currents to keep it from freezing up, and/or surface winds blowing the warmer (sun-heated) waters Northwards. Considering all the additional feedbacks, I'd say year round ice free poles could be a reality around 2035 at the very latest.

Dharma Rupa

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Re: When will the Arctic Go Ice Free?
« Reply #74 on: August 01, 2018, 12:37:33 AM »
A scenario of year-round ice-free Arctic can only be reached (IMO) by further a northward reach of the warm ocean currents.
I keep reading this dreamy misconception everywhere. People seem to be forgetting about the fact that the quantity of heat energy required to melt 1kg of ice (of just below freezing) to 1kg of water (of just above freezing) would raise the temperature of that same 1 kg of water to 80 degrees Celsius. This means that as soon as ice is gone, and there is heat energy (i.e. Sunlight), the oceans will be very hot at the surface (provided that surface T will also keep on rising as it does) all around the Arctic circle. It already is super anomalously warm, by the way. So when the sun is gone at the polar caps, all it needs is a little flow from warmer lower ocean currents to keep it from freezing up, and/or surface winds blowing the warmer (sun-heated) waters Northwards. Considering all the additional feedbacks, I'd say year round ice free poles could be a reality around 2035 at the very latest.

Don't know when, though I suspect soon, but with the first Summer the DMI 80N isn't pinned to nearly 0c the ice will not return for at least millennia.

liefde

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Re: When will the Arctic Go Ice Free?
« Reply #75 on: August 01, 2018, 12:41:00 AM »
A quick glance says that is a model study.  Care to demonstrate any skill at all in the models?
Assuming you can read; Care to read it again?

Dharma Rupa

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Re: When will the Arctic Go Ice Free?
« Reply #76 on: August 01, 2018, 02:07:24 AM »
A quick glance says that is a model study.  Care to demonstrate any skill at all in the models?
Assuming you can read; Care to read it again?


No.  I only pay attention to studies which have a demonstrated skill; which includes zero Global modeling studies.

crandles

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Re: When will the Arctic Go Ice Free?
« Reply #77 on: August 01, 2018, 02:51:31 AM »

Actually, no, that's not true; http://iopscience.iop.org/article/10.1088/1748-9326/9/12/124002;jsessionid=BC6F9B408139804AB3587C183EE22AAC.c1.iopscience.cld.iop.org

Maximum warming occurs a median of 10.1 years after the CO2 emission event and has a median value of 2.2 mK GtC−1.

Seems to use lots of different models, so I doubt that is much of a problem.

I could easily be misunderstanding, but my impression is that the oceans take hundreds of years to warm up. So how is this study arriving at maximum warming after 10.1 years?

I am not sure, but suspect this study is putting 100GtC into atmosphere. Half of that gets absorbed by oceans fairly quickly; practically too quickly for heating effect to be noticed before it is gone but then land, weathering, other sinks and new ocean water coming to the surface take up more of the carbon over various timescales. So the carbon level reaches its peak very quickly and then declines.

So I believe there is lots more heating to come as the oceans warm up but in the study there is probably fairly steady declining CO2 levels as time goes on. The ocean warming is most rapid to start with but slows down over time. Consequently after 10.1 years the declining CO2 level becomes more important than the ocean heating so there is a slow net cooling.

If I am understanding correctly:

The pulse injection followed by declining CO2 levels in this study may be interesting, but that is not what has happened and if you want to know what happens if we stabilise GG levels, then there is decades if not hundreds of years of warming to come, at declining rates, assuming other things also stay constant.

Emissions for next 1 or 10 years have some effect but compared to effects of past 50+years all still working to warm the oceans, current emissions are small and don't have much effect for some time. Rework the numbers with 20 years of rapid emission changes and then you start to see noticeable effect.

I don't think the study is wrong, but you are being mislead by it.

oren

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Re: When will the Arctic Go Ice Free?
« Reply #78 on: August 01, 2018, 03:48:22 AM »
A scenario of year-round ice-free Arctic can only be reached (IMO) by further a northward reach of the warm ocean currents.
I keep reading this dreamy misconception everywhere. People seem to be forgetting about the fact that the quantity of heat energy required to melt 1kg of ice (of just below freezing) to 1kg of water (of just above freezing) would raise the temperature of that same 1 kg of water to 80 degrees Celsius. This means that as soon as ice is gone, and there is heat energy (i.e. Sunlight), the oceans will be very hot at the surface (provided that surface T will also keep on rising as it does) all around the Arctic circle. It already is super anomalously warm, by the way. So when the sun is gone at the polar caps, all it needs is a little flow from warmer lower ocean currents to keep it from freezing up, and/or surface winds blowing the warmer (sun-heated) waters Northwards. Considering all the additional feedbacks, I'd say year round ice free poles could be a reality around 2035 at the very latest.

Don't know when, though I suspect soon, but with the first Summer the DMI 80N isn't pinned to nearly 0c the ice will not return for at least millennia.
liefde and DR your arguments sound right, but then again all the seasonally ice-free seas undergo the same summer heating only to freeze up again during winter. Such behavior is not going to go away the first year the arctic ocean gets above the DMI chart.

GoSouthYoungins

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Re: When will the Arctic Go Ice Free?
« Reply #79 on: August 01, 2018, 05:04:36 AM »

Actually, no, that's not true; http://iopscience.iop.org/article/10.1088/1748-9326/9/12/124002;jsessionid=BC6F9B408139804AB3587C183EE22AAC.c1.iopscience.cld.iop.org

Maximum warming occurs a median of 10.1 years after the CO2 emission event and has a median value of 2.2 mK GtC−1.

Ya, despite the Carnegie Institution for Science seeming very sciency and legit, this article doesn't make a lick of sense. It is all based on models and doesn't correspond to the history of how earth works. Not that that ever seems to bother the modelers, or those who reference their work.

The purported purpose of the study is to determine how long the lag in warming is for our real world, but then the scenario they choose to model is insanely unlike the situation we are actually. But let's just cut to the chase and look at why the conclusion is malarkey...

If we are currently experiencing the effects of warming from CO2 emissions up to 2008 (to slightly simply things), then 380 ppm should correspond to about 1C temperature rise. SO SO SO SO SO WRONG. Last time concentrations were that high was a few million years ago and the temperature was significantly higher, sea level was significantly higher, and there wasn't any significant ice in the northern hemisphere. More recently, the co2 to temperature correlation would suggest at least 5C of warming from a 280 to 380 increase.

big time oops

Wherestheice

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Re: When will the Arctic Go Ice Free?
« Reply #80 on: August 01, 2018, 07:00:30 AM »

Actually, no, that's not true; http://iopscience.iop.org/article/10.1088/1748-9326/9/12/124002;jsessionid=BC6F9B408139804AB3587C183EE22AAC.c1.iopscience.cld.iop.org

Maximum warming occurs a median of 10.1 years after the CO2 emission event and has a median value of 2.2 mK GtC−1.

Ya, despite the Carnegie Institution for Science seeming very sciency and legit, this article doesn't make a lick of sense. It is all based on models and doesn't correspond to the history of how earth works. Not that that ever seems to bother the modelers, or those who reference their work.

The purported purpose of the study is to determine how long the lag in warming is for our real world, but then the scenario they choose to model is insanely unlike the situation we are actually. But let's just cut to the chase and look at why the conclusion is malarkey...

If we are currently experiencing the effects of warming from CO2 emissions up to 2008 (to slightly simply things), then 380 ppm should correspond to about 1C temperature rise. SO SO SO SO SO WRONG. Last time concentrations were that high was a few million years ago and the temperature was significantly higher, sea level was significantly higher, and there wasn't any significant ice in the northern hemisphere. More recently, the co2 to temperature correlation would suggest at least 5C of warming from a 280 to 380 increase.

Well we haven’t gotten to 5c yet??
"When the ice goes..... F***

jdallen

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Re: When will the Arctic Go Ice Free?
« Reply #81 on: August 01, 2018, 08:50:16 AM »
That "yet" word again 😉
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Wherestheice

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Re: When will the Arctic Go Ice Free?
« Reply #82 on: August 01, 2018, 09:01:36 AM »
That "yet" word again 😉

haha. Climate science is a field of "Yet's". We can all project and predict, until the "yet's" start happening.
"When the ice goes..... F***

Wherestheice

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Re: When will the Arctic Go Ice Free?
« Reply #83 on: August 01, 2018, 09:05:17 AM »
That "yet" word again 😉

At the end of the day, nothing is under our control. Maybe nature decides to kill off humans, or maybe not. Only one way to find out, lol.
"When the ice goes..... F***

Wherestheice

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Re: When will the Arctic Go Ice Free?
« Reply #84 on: August 01, 2018, 09:14:34 AM »

Actually, no, that's not true; http://iopscience.iop.org/article/10.1088/1748-9326/9/12/124002;jsessionid=BC6F9B408139804AB3587C183EE22AAC.c1.iopscience.cld.iop.org

Maximum warming occurs a median of 10.1 years after the CO2 emission event and has a median value of 2.2 mK GtC−1.

Ya, despite the Carnegie Institution for Science seeming very sciency and legit, this article doesn't make a lick of sense. It is all based on models and doesn't correspond to the history of how earth works. Not that that ever seems to bother the modelers, or those who reference their work.

The purported purpose of the study is to determine how long the lag in warming is for our real world, but then the scenario they choose to model is insanely unlike the situation we are actually. But let's just cut to the chase and look at why the conclusion is malarkey...

If we are currently experiencing the effects of warming from CO2 emissions up to 2008 (to slightly simply things), then 380 ppm should correspond to about 1C temperature rise. SO SO SO SO SO WRONG. Last time concentrations were that high was a few million years ago and the temperature was significantly higher, sea level was significantly higher, and there wasn't any significant ice in the northern hemisphere. More recently, the co2 to temperature correlation would suggest at least 5C of warming from a 280 to 380 increase.

I will add that it is true that the last time co2 was this high, the world was much warmer and sea levels much higher. http://www.climatecentral.org/news/the-last-time-co2-was-this-high-humans-didnt-exist-15938

I will also add that the co2 levels have been rising much faster than any previous warming periods, https://mashable.com/2016/03/21/co2-fastest-66-million-years/

So its a bit interesting considering we have warmed only about 1.2-1.5 c with that rapid amount of change, things seem to be picking up though....

The more I think about it, things point to a rapid rise in temp. Only questions is how much and when....
"When the ice goes..... F***

misfratz

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Re: When will the Arctic Go Ice Free?
« Reply #85 on: August 01, 2018, 11:01:47 AM »
Even if existing concentrations could be immediately stabilized, temperature would continue to increase by an estimated 1.1°F (0.6°C) over this century, relative to 1980–1999.
Correct me if I'm wrong, but that seems to indicate that temperatures will continue to increase throughout the century even if we stop emissions. And we're already over 400 ppm. My guess is that we have enough C02 in the atmosphere to get an ice free day in the arctic, even if civilization collapsed totally tomorrow.
No, you are confusing two different things: emissions and concentrations - which is really easy to do.

If present-day concentrations of GHG could be stabilised then there would be warming still in the pipeline to come.

If emissions of GHG are stopped entirely then GHG concentrations will decline somewhat, and this will roughly cancel out the temperature increase lag effect, so that you would expect global temperatures to stabilise at about the same level they are at now. Since it takes some while for ice to melt in response to elevated temperatures you would expect to see some continued decline in Arctic sea-ice levels - probably to an ice-free state (as an aside the likely sensitivity of Arctic sea-ice to present-day conditions is probably one reason why coupled GCMs are on the conservative side when it comes to Arctic sea-ice predictions, due to the way in which those models are developed).

It's actually pretty hard to stabilise GHG concentrations at their current elevated level. Either they continue increasing, or they start to decline (this decline happens at different speeds due to different processes). The stabilisation scenario is simply an interesting "what-if?" scenario that is easy to set up with a GCM. I tend to think that if we suddenly became really serious about tackling GHG, in a Apollo project or World War fighting sort of way, that we could do better than a stabilisation scenario. I just don't see the political route to that seriousness.
« Last Edit: August 01, 2018, 01:50:45 PM by misfratz »

Richard Rathbone

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Re: When will the Arctic Go Ice Free?
« Reply #86 on: August 01, 2018, 12:30:17 PM »
As far as FYI goes, its very sensitive to current conditions as each year is a new one. This same sensitivity means that whenever temperature stabilises, so does the trend in sea ice extent.

Lou

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Re: When will the Arctic Go Ice Free?
« Reply #87 on: August 01, 2018, 06:39:02 PM »
It is madness. Worse than pure denial of the entire situation. I'm less bothered by those who think it is all an elite globalist ploy to enslave the masses, than I am by those who engage with the data on a daily basis but come to the conclusion that mild solutions will be sufficient to save civilization.  OR for that matter those who think that it is no big deal to change the climate drastically and kill off humanity cuz the earth will bounce back.  Are we really going to successfully prevent nuclear war as everything falls apart? Are we really going to successfully decommission the hundreds of nuclear power plants around the world? Even if you aren't bothered by the collapse of civilization and the horrible deaths of billions of people, the possibility of turning the earth into a planet like venus or mars should give you some pause.

While I agree with your whole post, the quoted graf really resonated with me.  I find it astonishing how many people, many of them real, honest-to-Pete scientists, see the data and the (often conservative yet terrifying) projections, and aren't standing on tables screaming about this mess we've created.  Just as bad are the environmental activists who will argue that you can't tell mainstreamers the full truth about CC or "you'll scare them away".  (I've had that argument numerous times with local enviros.)

Barring some nearly miraculous ramping up of carbon removal and sequestration, there is no way we'll avoid something between horrific consequences and a full-blown, worldwide catastrophe.

As for the topic of this thread, while I missed the voting window, I would definitely have voted for the 2020-2025 period.  Trends plus variability means we won't need some wildly improbable set of events in a given summer to hit <1M km^2.  I would also predict it gets no more than 60 seconds of, "Golly, look at that!" coverage on TV news, with the usual suspects talking about the economic benefits of newly-opened shipping routes every summer.

josh-j

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Re: When will the Arctic Go Ice Free?
« Reply #88 on: August 01, 2018, 07:02:31 PM »
A scenario of year-round ice-free Arctic can only be reached (IMO) by further a northward reach of the warm ocean currents.
I keep reading this dreamy misconception everywhere. People seem to be forgetting about the fact that the quantity of heat energy required to melt 1kg of ice (of just below freezing) to 1kg of water (of just above freezing) would raise the temperature of that same 1 kg of water to 80 degrees Celsius. This means that as soon as ice is gone, and there is heat energy (i.e. Sunlight), the oceans will be very hot at the surface (provided that surface T will also keep on rising as it does) all around the Arctic circle. It already is super anomalously warm, by the way. So when the sun is gone at the polar caps, all it needs is a little flow from warmer lower ocean currents to keep it from freezing up, and/or surface winds blowing the warmer (sun-heated) waters Northwards. Considering all the additional feedbacks, I'd say year round ice free poles could be a reality around 2035 at the very latest.

But water is not just stagnant in the Arctic and waiting to warm. While its true that a lot more heat can go into the water once there's no ice to melt, its also the case that the worlds oceans are very large, very deep, and circulating. I find it hard to believe that mainstream science is so wrong on the timescales for a year-round BOE. I'm not saying the current mainstream predictions are gospel and won't change, but 2035 is so at odds with the mainstream view that I find it hard to accept. No ice in winter also means more can escape, does it not? (No really, correct me if I'm wrong - I'm no expert!)

GoSouthYoungins

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Re: When will the Arctic Go Ice Free?
« Reply #89 on: August 01, 2018, 07:50:27 PM »
I find it hard to believe that mainstream science is so wrong on the timescales for a year-round BOE. I'm not saying the current mainstream predictions are gospel and won't change, but 2035 is so at odds with the mainstream view that I find it hard to accept.

The mainstream science said 2005, 2007, 2012, 2016 will occur a couple decades from now. Mainstream science is funded by those in power. Those in power don't want to drastically change everything.  The science they fund reliable says that the serious effects will occur just outside the lifespans of the voting public. Contrary opinions & evidence get shunned.

The most telling example is the IPCCs most recent report which estimated that under a worst case scenario, arctic ice extent would retreat to a minimum 3.5 million sq kilometers in the 2030s. This was based on their video games...I mean models. In reality, extent had already had a minimum below this amount PRIOR TO THE PUBLICATION OF THE IPCC'S REPORT!!!

When reality points towards needing drastic and immediate change, it is safe to assume that mainstream science will be outrageously inaccurate.
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Steven

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Re: When will the Arctic Go Ice Free?
« Reply #90 on: August 01, 2018, 09:21:53 PM »
The most telling example is the IPCCs most recent report which estimated that under a worst case scenario, arctic ice extent would retreat to a minimum 3.5 million sq kilometers in the 2030s. This was based on their video games...I mean models. In reality, extent had already had a minimum below this amount PRIOR TO THE PUBLICATION OF THE IPCC'S REPORT!!!

No, it hasn't.  The IPCC uses a 5-year running average of the September sea ice extent.  The lowest value for this metric so far is 4.6 million km2, which is the average September extent for the 5 years 2012-2016.

Below is one of the relevant figures of the latest IPCC report.  The thick colored lines are the ones they used for their main assessment.



gerontocrat

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Re: When will the Arctic Go Ice Free?
« Reply #91 on: August 01, 2018, 09:44:18 PM »
The most telling example is the IPCCs most recent report which estimated that under a worst case scenario, arctic ice extent would retreat to a minimum 3.5 million sq kilometers in the 2030s. In reality, extent had already had a minimum below this amount PRIOR TO THE PUBLICATION OF THE IPCC'S REPORT!!!

No, it hasn't.  The IPCC uses a 5-year running average of the September sea ice extent.  The lowest value for this metric so far is 4.6 million km2, which is the average September extent for the 5 years 2012-2016.

Below is one of the relevant figures of the latest IPCC report.  The thick colored lines are the ones they used for their main assessment.

And that 5-year average has gone up as 2012 left the average.

Table of 5 year averages - that year and previous 4 years
NSIDC Sept Av
                JAXA daily min
2009    5.20     4.88
2010    5.07     4.77
2011    4.80     4.50
2012    4.66     4.32
2013    4.79     4.39
2014    4.77     4.35
2015    4.72     4.28
2016    4.73     4.23
2017    4.97     4.49

« Last Edit: August 01, 2018, 09:57:24 PM by gerontocrat »
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Dharma Rupa

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Re: When will the Arctic Go Ice Free?
« Reply #92 on: August 02, 2018, 12:42:37 AM »
The most telling example is the IPCCs most recent report which estimated that under a worst case scenario, arctic ice extent would retreat to a minimum 3.5 million sq kilometers in the 2030s. This was based on their video games...I mean models. In reality, extent had already had a minimum below this amount PRIOR TO THE PUBLICATION OF THE IPCC'S REPORT!!!

No, it hasn't.  The IPCC uses a 5-year running average of the September sea ice extent.  The lowest value for this metric so far is 4.6 million km2, which is the average September extent for the 5 years 2012-2016.

Below is one of the relevant figures of the latest IPCC report.  The thick colored lines are the ones they used for their main assessment.




I must admit to being a bit confused about your response, though I haven't checked out the actual numbers.  GoSouthYoungins didn't say that IPCC contradicted their own numbers.  Cir said that the IPCC's numbers contradicted generally accepted data.

Michael Hauber

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Re: When will the Arctic Go Ice Free?
« Reply #93 on: August 02, 2018, 01:02:39 AM »

If we are currently experiencing the effects of warming from CO2 emissions up to 2008 (to slightly simply things), then 380 ppm should correspond to about 1C temperature rise. SO SO SO SO SO WRONG. Last time concentrations were that high was a few million years ago and the temperature was significantly higher, sea level was significantly higher, and there wasn't any significant ice in the northern hemisphere. More recently, the co2 to temperature correlation would suggest at least 5C of warming from a 280 to 380 increase.

The graph you supplied is for temperature at Vostok (Antarctica) not global temps.  Also note that the primary temperature driver over this period was orbital changes - and then the temp changes drove CO2, and Co2 provided an additional feedback to warming.  So 5C in Antarctica is reduced by about half to get a global value, and then further reduced by however much of the warming was caused by orbital changes.
Climate change:  Prepare for the worst, hope for the best, expect the middle.

Dharma Rupa

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Re: When will the Arctic Go Ice Free?
« Reply #94 on: August 02, 2018, 02:46:57 AM »

If we are currently experiencing the effects of warming from CO2 emissions up to 2008 (to slightly simply things), then 380 ppm should correspond to about 1C temperature rise. SO SO SO SO SO WRONG. Last time concentrations were that high was a few million years ago and the temperature was significantly higher, sea level was significantly higher, and there wasn't any significant ice in the northern hemisphere. More recently, the co2 to temperature correlation would suggest at least 5C of warming from a 280 to 380 increase.

The graph you supplied is for temperature at Vostok (Antarctica) not global temps.  Also note that the primary temperature driver over this period was orbital changes - and then the temp changes drove CO2, and Co2 provided an additional feedback to warming.  So 5C in Antarctica is reduced by about half to get a global value, and then further reduced by however much of the warming was caused by orbital changes.

Let's start with stating that the theory of orbital changes as a primary driver as if it were a demonstrated fact, and then move on to wondering where you came up with cutting the Antarctic value in half, and then in half again.

I will agree that the orbital variation seems to have a part to play, but I will not agree that its role has been demonstrated, but even assuming that, where do you come up with the rest of your statement????

GoSouthYoungins

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Re: When will the Arctic Go Ice Free?
« Reply #95 on: August 02, 2018, 02:48:19 AM »
so does anyone disagree with the spirit of what i am saying, or is it simply that 5C increase in Antarctic temps is no big deal ( which is used cuz its the best record available, due to its long term stability, hence GO SOUTH YOUNGINS ) ? Does anyone actually believe there is only a 10.1 year lag? It just doesn't pass the smell test. It flies in the face of everything that I would like to think that everyone who follows ARCTIC ICE understands about the climate system. I would be thrilled if somebody can explain to me how the effects of a 10.1 year lag makes sense. Ill pop the champagne I have in the fridge (even though I don't drink) and just shoot it all over my house. I understand that IPCC takes care to make sure that they can't be pinned down and discredited in the short term on a hard a fast data point, but that doesn't make the message they are conveying dangerously misleading.

I understand why the article reaches the conclusion that they do. They model an enormous instant increase in CO2, and then let their video game play out. So there is an extreme amount of dispersion into the ocean and the land biosphere which reduces the atmospheric concentrations very rapidly. Too bad that has NO CORRELATION to the actual situation, which is what they claim to be trying to provide information for.

Our sinks are starting to fill up. The ocean is getting full. And there is no short or medium term path towards reduction in emissions. The land we are paving at a rate which will soon overcome what the unpaved can make up for. Soon the unprecedented rise in atmospheric GHGs will cause ecology to start burning globally which will be a stick of TNT in the sink. The idea expressed by the Carnegie folks is dangerous, and it makes me sad that ppl ( even FUCKING HERE ) are lulled to pseudo-complacency by it.
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bluesky

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Re: When will the Arctic Go Ice Free?
« Reply #96 on: August 02, 2018, 08:03:14 AM »
warming we are feeling now is mostly from GHG emissions from decades ago. GHGs are like a lid on a pot; as the lid gets thicker the stuff in the pot gets warmer, but it takes some time...in this case probably 20-30 years. The warming we have seen so far is primarily from emissions up to 1990, so about 350 ppm.
Actually, no, that's not true; http://iopscience.iop.org/article/10.1088/1748-9326/9/12/124002;jsessionid=BC6F9B408139804AB3587C183EE22AAC.c1.iopscience.cld.iop.org

Maximum warming occurs a median of 10.1 years after the CO2 emission event and has a median value of 2.2 mK GtC−1.

We now can reasonably deny the validity to apply this research paper to polar amplification without a shade of doubt:

Palaeoclimate constraints on the impact of 2° C anthropogenic warming and beyond (P. Bakker et al ), Nature Geoscience June 2018

free version:
http://eprints.esc.cam.ac.uk/4301/2/41561_2018_146_MOESM1_ESM.pdf

The paper is very well articulated and documented, probably the most updated paper on past reconstruction of warming events due to orbital forcing and GHG, the main purpose of the paper is to back test the validity of the models -used for our current man made GW-  to these paleoclimatic events.

on page 4 of the article, we can read the following:

"The MPWP (mid-Pliocene warm period 3.3–3.0 million years ago)
  was subject to intermittently elevated CO2 (potentially up to 450 ppm)
compared to the HTM (Holocene Thermal Maximum)  and the LIG9 (last Interglacial).
The CO2 concentration at that time was most similar to the RCP2.6
scenario, and a factor of three-to-four less than concentrations
expected by ad 2100 for the RCP8.5 scenario. Climate models
simulate an increase in tropical temperatures by 1.0–3.1 °C (for
RCP2.6 CO2 forcing of 405 ppmv (ref. 2)), generally in line with
MPWP proxy reconstructions at low latitudes127. Strong polar
amplification is observed for the MPWP. For example, proxy data
from the North Atlantic and northeastern Russian Arctic indicate a
rise of surface air temperatures by 8 °C (ref. 128) during the MPWP
and even higher in the early Pliocene129. These regional temperature
changes are similar to projected warming at ad 2100 for the RCP8.5
scenario, in spite of the much lower CO2 rise during the MPWP,
and suggest that current models may underestimate the warming
response in the Arctic130 to increased CO2 concentrations."





binntho

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Re: When will the Arctic Go Ice Free?
« Reply #97 on: August 02, 2018, 08:09:03 AM »

Let's start with stating that the theory of orbital changes as a primary driver as if it were a demonstrated fact, and then move on to wondering where you came up with cutting the Antarctic value in half, and then in half again.

I will agree that the orbital variation seems to have a part to play, but I will not agree that its role has been demonstrated, but even assuming that, where do you come up with the rest of your statement????

How many factors can influence the climate? The clear cyclical glaciation - intermediate - glaciation signal over the last 2 million years or so match the Milankovich cycles to such a degree that I think it is safe to say that orbital variation is the accepted explanation for the warming during intermediaries and cooling during glaciations.

The Vostock core shows that in the Antarctic, the four last intermediary temperature maxima reached some 5 degrees C above present  (which is usually centered on 1970 in palaeoclimate terms), with our Holocene climate maximum being slightly lower, at some 3-4 degrees C above present. (Note that the Vostock core was drilled in 1995, but meaningful data can only really be extracted from ice that is quite old, on a scale of centuries if not millennia).

Global temperature during the Holocene show that the Holocene climate maximum was less than 1 degree C warmer than present time (i.e. 1970) - which seems to indicate that the maximum at Antarctica was some 4 times higher than the global maximum.

Research in the northern hemisphere (mainly Europe) seems to indicate that the Holocene maximum was much stronger the closer to the (North) pole one goes. So the Holocene maximum (and other intermediary maxima) may well have been exaggerated towards the poles.

Previous rapid warming events over the last 2 million years, when going from glaciation to intermediary, were caused by orbital change with added feedback from CO2 and methane. The current rapid warming goes against the effects of orbital change (the climate should be cooling rapidly) and is mainly caused by a large increase in CO2, so it is reasonable to expect the pattern of warming being different this time.

Wherestheice

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Re: When will the Arctic Go Ice Free?
« Reply #98 on: August 02, 2018, 08:54:56 AM »

Let's start with stating that the theory of orbital changes as a primary driver as if it were a demonstrated fact, and then move on to wondering where you came up with cutting the Antarctic value in half, and then in half again.

I will agree that the orbital variation seems to have a part to play, but I will not agree that its role has been demonstrated, but even assuming that, where do you come up with the rest of your statement????

How many factors can influence the climate? The clear cyclical glaciation - intermediate - glaciation signal over the last 2 million years or so match the Milankovich cycles to such a degree that I think it is safe to say that orbital variation is the accepted explanation for the warming during intermediaries and cooling during glaciations.

The Vostock core shows that in the Antarctic, the four last intermediary temperature maxima reached some 5 degrees C above present  (which is usually centered on 1970 in palaeoclimate terms), with our Holocene climate maximum being slightly lower, at some 3-4 degrees C above present. (Note that the Vostock core was drilled in 1995, but meaningful data can only really be extracted from ice that is quite old, on a scale of centuries if not millennia).

Global temperature during the Holocene show that the Holocene climate maximum was less than 1 degree C warmer than present time (i.e. 1970) - which seems to indicate that the maximum at Antarctica was some 4 times higher than the global maximum.

Research in the northern hemisphere (mainly Europe) seems to indicate that the Holocene maximum was much stronger the closer to the (North) pole one goes. So the Holocene maximum (and other intermediary maxima) may well have been exaggerated towards the poles.

Previous rapid warming events over the last 2 million years, when going from glaciation to intermediary, were caused by orbital change with added feedback from CO2 and methane. The current rapid warming goes against the effects of orbital change (the climate should be cooling rapidly) and is mainly caused by a large increase in CO2, so it is reasonable to expect the pattern of warming being different this time.

That’s interesting. Things are definitely much different than anything ever before. I would say what’s happening now is unprecedented in earths history. The question that looms is, how much will things be different, quite substantially different imo.
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Pmt111500

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Re: When will the Arctic Go Ice Free?
« Reply #99 on: August 02, 2018, 09:08:47 AM »
Have humans altered ocean currents enough to produce an interglacial simulate of Dansgaard-Oeschger events (+3,5-4 over deep glacial climate)? Maybe we need a new term for this? Anthropogenic End-of-glacial Extreme Hyperthermal, A-EEH!?!? Off to pick some berries. 
Amateur observations of Sea Ice since 2003.