There is an error in this poll. No option for anything above 2100. Should have at least one option After 2100/not in foreseeable future/never.
There is an error in this poll. No option for anything above 2100. Should have at least one option After 2100/not in foreseeable future/never.
Edit made and you can change your vote, i'm guessing you were the vote for 2080-2100, so you can change now. 8)
I'd prefer a 2023-2027 option :)
There is an error in this poll. No option for anything above 2100. Should have at least one option After 2100/not in foreseeable future/never.
Edit made and you can change your vote, i'm guessing you were the vote for 2080-2100, so you can change now. 8)
Thnx :) Doesn't seem to let me change at the moment.
I've edited the poll.
And voted 2030-2040.
Should have at least one option After 2100/not in foreseeable future/never.Ah.... an AGW denier who knows the solar TSI will continue...into the foreseeable future/never..... at a subnormal irradiation level, as it has for the last 12+ years (including a 3+ year period setting a 100 year record low).
Should have at least one option After 2100/not in foreseeable future/never.Ah.... an AGW denier who knows the solar TSI will continue...into the foreseeable future/never..... at a subnormal irradiation level, as it has for the last 12+ years (including a 3+ year period setting a 100 year record low).
And voted 2030-2040.
And voted 2030-2040.
Same as Neven [2030-2040].
And the same as my vote on when will PIOMAS be less than 1,000 km3.
I'm curious to know why both of you opine that period. Thanks.
And voted 2030-2040.
Same as Neven [2030-2040].
And the same as my vote on when will PIOMAS be less than 1,000 km3.
I'm curious to know why both of you opine that period. Thanks.
Me as well
My 'guess' is increasing cloudiness and snow cover due to a change in normal past arctic climate/weather from global climate changes .... but I don't like making assumptions or guesses as to what others think or why, so I asked.
These polls keep coming up, I thought I just missed voting in one that looked like this.
This is an easy vote as I don't know the answer but the bin 2020-2025 spans 6 years in the near future. That's my choice.
It doesn't look like it is going to be this year, so the 2018-2020 bin only has two potentially realistic years and so can't compete with the 6 years in the second bin. The year 2020 is in both bins so the only year the first bin really has going for it is next year, 2019.
The bins after that are disfavored because the event may well have already happened prior to the years in those bins.
Comment: it looks a little strange to have the bins overlapping by one year. For example, the year 2020 is in both of the first 2 bins. This could have been avoided (and my vote made more difficult) by reducing the second bin to the 5-year interval 2021-25. Similarly, the later bins could be changed to begin in years starting with either a '1' or a '6'.
Also, the units should be km^2, not just km.
“It is getting interesting.”
“Interesting” - is that what you call it when you reach the top of roller coaster, head down the slope at high speed, only to see that ahead of you there is no track?! - that it has been torn down!
As current volume trends continue, we are looking at the first ice free arctic September in 2022-23 plus or minus a few years. Subtract a year for breaking through the 1 million square kilometer “ice free” level.
After that, the wheels come off and we enter free fall. The atmospheric and oceanic circulations are already changing in major ways. Soon that will be dramatic. Not long after that the conditions will be properly described as extreme. And then to use your word - things get “exciting”.
Sadly, I am going to get to live long enough to see us all the way through to a year round ice free arctic. I am not looking forward to that, or to the inevitable droughts, pandemics, deluges, wars, disease, and climate catastrophes that will come with it.
I am only thankful that I will not live long enough to see an ice free Greenland.
I fully expect to die in the foregoing disasters long before then.
Sam
in general one can look at things the way you do but until we see year-round ice-free arctic it will take centuries IMO while ice free Augusts and Septembers are most probable to happen not too far out IMO.
I think a year round ice free Arctic is only a few decades away. We need to recognize that once we get the blue ocean event there will be rapid amounts of warming from the latent heat effect as well as loss of albedo that will inhibit ice from re-freezing. The age of ice in the Arctic is coming to an end.
If the solar TSI remains low for a while longer, the Arctic will still be ice-free by 2020-2040. But, solar nuclear physics demands solar TSI WILL rise back to normal & higher, in the future. Then, AGW effects & feedbacks will take off at a rate, Earth economics can't adjust for, because wide ranging AGW deniers' propaganda has been at work for decades.The chances of an ice free arctic not happening till then is probably really low anywaysShould have at least one option After 2100/not in foreseeable future/never.Ah.... an AGW denier who knows the solar TSI will continue...into the foreseeable future/never..... at a subnormal irradiation level, as it has for the last 12+ years (including a 3+ year period setting a 100 year record low).
I agree with Wherestheice.I think 2022-2023 is still early. I'm putting thinking a sub-1 million KM2 September extent won't arrive until 2030 +/- a couple.
Based on current volume trends -
1st completely ice free September Arctic Ocean 2022-2023 +/- 2
1st completely ice free year-round Arctic Ocean 2035-2050
1st I’ve free Greenland & northern hemisphere 100-250 years after that
Maybe sooner - depending on feedbacks
<snippage>
I agree with Wherestheice.I think 2022-2023 is still early. I'm putting thinking a sub-1 million KM2 September extent won't arrive until 2030 +/- a couple.
Based on current volume trends -
1st completely ice free September Arctic Ocean 2022-2023 +/- 2
1st completely ice free year-round Arctic Ocean 2035-2050
1st I’ve free Greenland & northern hemisphere 100-250 years after that
Maybe sooner - depending on feedbacks
<snippage>
I don't think we'll see a year round ice free Arctic for at least a couple of centuries. As long as there's 3 million+ KM3 of ice sitting on Greenland, combined with "cold continents" I think most of the CAB will refreeze annually.
I agree with Wherestheice.I think 2022-2023 is still early. I'm putting thinking a sub-1 million KM2 September extent won't arrive until 2030 +/- a couple.
Based on current volume trends -
1st completely ice free September Arctic Ocean 2022-2023 +/- 2
1st completely ice free year-round Arctic Ocean 2035-2050
1st I’ve free Greenland & northern hemisphere 100-250 years after that
Maybe sooner - depending on feedbacks
<snippage>
I don't think we'll see a year round ice free Arctic for at least a couple of centuries. As long as there's 3 million+ KM3 of ice sitting on Greenland, combined with "cold continents" I think most of the CAB will refreeze annually.
I think it would be very surprising if the Arctic wasn't ice free year round after another 2-4 decades.The main-stream view (a couple centuries+) has a 3 million KM3+ gorilla supporting it - The Greenland Ice Cap.
I think it would be very surprising if the Arctic wasn't ice free year round after another 2-4 decades. The amount of heat that will be in the Arctic after it goes ice free is truly scary. All that energy that melts the ice.....once there is no more ice to melt it will make things hot, really hot, and that will make it hard for the ice to refreeze. We are already seeing these warm winters. I think the Arctic going ice free year round in a couple centuries seems to be the mainstream view, but things are changing very rapidly. I can't say I agree, but at the end of the day nature will play how it wants not my or your thoughts.I disagree. Even with storms, clouds, humidity, fog and whatever not - when the sun doesn't shine for 6 months, with the vagaries of weather there will come a calm clear day when temps fall below -10oC, and the surface will freeze somewhere in the central arctic basin. IMHO what could prevent such freezing is a major change of arctic ocean circulation, which could well happen at some point but not in a few decades.
I come down on the side of a few decades before the Arctic will be ice free year round. If we extrapolate from the volume decline the prediction is 2023 +- 2 for the first ice free summer days and 2053 for the first ice free year. Currently the average year to year volume decline is still increasing. If the trends are correct by 2035 we should see the Arctic Ice free from about July 1st. That means three months of insolation doing nothing but warming the ocean. The combination of the extra heat in the ocean combined with more dynamic activities would seem to suggest a shorter time to ice free all year rather than a longer period.I think it would be very surprising if the Arctic wasn't ice free year round after another 2-4 decades.I disagree. Even with storms, clouds, humidity, fog and whatever not - when the sun doesn't shine for 6 months, with the vagaries of weather there will come a calm clear day when temps fall below -10oC, and the surface will freeze somewhere in the central arctic basin. IMHO what could prevent such freezing is a major change of arctic ocean circulation, which could well happen at some point but not in a few decades.
The amount of heat that will be in the Arctic after it goes ice free is truly scary. All that energy that melts the ice.....once there is no more ice to melt it will make things hot, really hot, and that will make it hard for the ice to refreeze.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.The amount of heat that will be in the Arctic after it goes ice free is truly scary. All that energy that melts the ice.....once there is no more ice to melt it will make things hot, really hot, and that will make it hard for the ice to refreeze.This applies to every seasonal ice zone in the world, and yet (to give but one example) Hudson Bay refreezes every winter.
I think it would be very surprising if the Arctic wasn't ice free year round after another 2-4 decades.The main-stream view (a couple centuries+) has a 3 million KM3+ gorilla supporting it - The Greenland Ice Cap.
That mass of ice will dominate regional temperatures until it's gone. It will also dominate local circulation which along with the winter cold pool on the continents will create regional conditions sufficiently cold to permit enough heat to be dissipated in winter to permit local refreeze at the very least, if not a full refreeze of the ocean. The behavior of the system annually will come to resemble that currently in play in regions like Hudson Bay, the Bering, the Okhostk and Labrador seas.
Even after that local conditions will probably permit freezing in the CAA and along the continental margins for even longer after that.
We already have parts of the arctic ice-free all year round, reaching up to above 80 degrees north of Svalbard.
The ocean currents are well able to maintain an ice-free state through 6 months of darkness, but as Oren points out, this would require quite some reconfiguration of the current currents (!) for the whole Arctic to become ice-free through winter.
observations and citations support the conclusion that most global climate model results in the CMIP5 archive are too conservative in their sea ice projections. Recent data and expert opinion should be considered in addition to model results to advance the very likely timing for future sea ice loss to the first half of the 21st century, with a possibility of major loss within a decade or two.
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 1976–2005), under all plausible future climate scenarios
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.
We already have parts of the arctic ice-free all year round, reaching up to above 80 degrees north of Svalbard.
The ocean currents are well able to maintain an ice-free state through 6 months of darkness, but as Oren points out, this would require quite some reconfiguration of the current currents (!) for the whole Arctic to become ice-free through winter.
each warm current has it's counterpart which is why svalbard can be ice-free and st. lawrence can be frozen.
Gerontocrat -
If we trigger the release of the ~1,600 gigatons of carbon in the methane and carbon stores of the Arctic planes and the tundra, it is game over. The earth will go to the hot earth stable state. The Arctic will melt rapidly. The Antarctic will take substantially longer, but will also completely melt before CO2 levels can reduce.
Once that happens, the Earth reenters a climate state that we do not understand how to model - the equable climate. That isn't a bad place once we get there. The pressure is higher along with O2 percentage (30%) and temperature. Wet forests burn in the rain. Giant insects become common as O2 transport becomes easy.
The problem is in getting there. In the interim, the oceans go anoxic. O2 levels plummet to 14%. Large animals die from insufficient O2 unless they have extreme high altitude adaptations. Iron falls out of the oceans. Shelled creatures all but vanish as the oceanic pH falls. All of the biomes are disrupted and most species die off leading to an evolutionary explosion as the survivors move to fill all of the vacant evolutionary niches.
In the end it becomes a massively good thing as new life flourishes on the graves of the last failed attempt. New adaptations take over and dominate.
The problem there is that we only have about 500 million years left to leave the Earth before we begin the terminal slide to a lifeless Earth as the goldilocjs zone moves outward with an ever hotter aging sun. By 750 million years, large life cannot exist. By a billion, life is done as the thermal runaway begins.
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/):Quoteover 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
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.
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.
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.
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.
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.
QuoteEven 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.
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.
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.
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.
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.
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.
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)
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.
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.
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.
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):
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
A quick glance says that is a model study. Care to demonstrate any skill at all in the models?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 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.
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.
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?
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?
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.
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.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.
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.
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.
That "yet" word again 😉
That "yet" word again 😉
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.
No, you are confusing two different things: emissions and concentrations - which is really easy to do.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.
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.
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.
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 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!!!
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.
| 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 |
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.
(https://i.imgur.com/AWypBVq.png)
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.
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.
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.
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????
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.
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.
...I will quibble only with the parenthetical "the climate should be cooling rapidly" due to Milankovich forcing. Without AGW, I understand Earth's climate would be cooling slowly during my lifetime (that is, on a human scale), although I'll accept "rapidly" in the geological scheme of things.
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.
Yeah well that partly depends on how you look on the early anthropocene hypothesis, Holocene was exeptionally long for an interglacial so it could be a thousand year plunge to the next glacial would be on already. Agree that a thousand years is still quite slow for a human timescale, f.e. I don't even know any of my ancestors that far back :o 8) :P ::) . But some people know, so maybe this is rapid....I will quibble only with the parenthetical "the climate should be cooling rapidly" due to Milankovich forcing. Without AGW, I understand Earth's climate would be cooling slowly during my lifetime (that is, on a human scale), although I'll accept "rapidly" in the geological scheme of things.
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.
Let’s try to stay on topic
Let’s try to stay on topic
this is on topic IMO, or don't you think that looking into the past will help to understand mechanisms as well as the relevance of positive and negative feedbacks as well as seeing repeating patterns that help to come to better conclusions?
if we have an opinion about when the arctic will become ice-free it's good practice to underline our opinion with know facts from the past and weigh them in the process, else we can play the lottery.
Given the recent rapid melt in the Arctic despite having a season not overly conducive to melt, I think a summer BOE event could be just one disastrous melt season away. If we were to get 2007 conditions next year, we could see our first BOE event IMHO.
A BOE in the summer does not, however, guarantee another BOE in the following summer. As we saw in both 2007 and 2012, the melt season minimums bounced back the following seasons, although at a new lower level. I would expect the melt seasons after the 1st BOE to exhibit similar behaviors, bouncing back to another new, lower level.
The decrease in NSIDC minimum extent between 2007 and 2012 was 0.76 (million square km) from 4.15 to 3.39.
I would suggest, therefore, that we might be more than one super-melt summer away from a summer below 1 million square km.
Given the recent rapid melt in the Arctic despite having a season not overly conducive to melt, I think a summer BOE event could be just one disastrous melt season away. If we were to get 2007 conditions next year, we could see our first BOE event IMHO.
A BOE in the summer does not, however, guarantee another BOE in the following summer. As we saw in both 2007 and 2012, the melt season minimums bounced back the following seasons, although at a new lower level. I would expect the melt seasons after the 1st BOE to exhibit similar behaviors, bouncing back to another new, lower level.
I wouldn't be surprised to see a BOE in the next year or two, only to not see another for five years, then get them two years running, etc.
And I am pretty sure, that the Hudson Bay as well as the North Pole will always* freeze in winter. On the North Pole you have 180 days of no sunlight, that will always be much below zero, no matter what. Average temperature in Winter is around -30°C at the North Pole and -20°C over most of Hudson Bay. So even if temperaturs would raise globally by 15°C, it would still be well below freezing in many areas there and therefore ice would form.Shouldn't we be looking at the Hudson bay to go blue ocean year-long, long before the CAB does?!!Actually, counter intuitively, the greater probability is that it will continue to freeze after the CAB becomes "ice free" - less than 1 million KM2 of ice in winter.
I agree.
Even after a summer BOE, ice will still form in the Arctic during the dark, polar winter for many decades. This cover of FYI will look and behave differently, likely thinner due to warmer winters, more mobile even in the dead of winter and more susceptible to melt the following melt season. This is no different than what we are observing in the peripheral seas in the basin. The Beaufort and Chukchi froze late and the resulting ice was far thinner and, as can be seen this year, will melt out despite conditions not conducive to melt.
And I am pretty sure, that the Hudson Bay as well as the North Pole will always* freeze in winter. On the North Pole you have 180 days of no sunlight, that will always be much below zero, no matter what. Average temperature in Winter is around -30°C at the North Pole and -20°C over most of Hudson Bay. So even if temperaturs would raise globally by 15°C, it would still be well below freezing in many areas there and therefore ice would form.Shouldn't we be looking at the Hudson bay to go blue ocean year-long, long before the CAB does?!!Actually, counter intuitively, the greater probability is that it will continue to freeze after the CAB becomes "ice free" - less than 1 million KM2 of ice in winter.
I agree.
Even after a summer BOE, ice will still form in the Arctic during the dark, polar winter for many decades. This cover of FYI will look and behave differently, likely thinner due to warmer winters, more mobile even in the dead of winter and more susceptible to melt the following melt season. This is no different than what we are observing in the peripheral seas in the basin. The Beaufort and Chukchi froze late and the resulting ice was far thinner and, as can be seen this year, will melt out despite conditions not conducive to melt.
I'm quoting here from the Melt Season thread cuz it makes more sense to discuss here:
I idea that the north pole will freeze for over for at least the next new thousand years because it is dark for half the year doesn't hold up to scrutiny because there are already areas north of 80N that have gone the past year without any ice. Not only no ice, but very warm SSTs. The ocean will continue to warm. The atmosphere will continue to warm. The Atlantic will encroach and the ice will retreat.
Also, it is kinda a "humpty dumpty situation". Once the ice melts in the summer, there will be mixing. The salinity of the water nearest to the surface will increase and refreeze will be more difficult. The salinity around the entirety of greenland and west into the CAA has already started to show significant increase. Once the summer ice melts, its much more difficult for it to be put back together again.
This process will take several years, but there are so many forcing to hurt ice, and very few to help. A big one that is rarely discussed in the likely drastic increase of soot from increased wildfires north of 60N. Layer greenland and the remaining arctic ice with black particles and all the models and predictions go out the window. Thousands of years becomes decades.
If global temperature rise 15 degrees C, there WILL NOT be any sea ice in the northern hemisphere. And there WILL NOT be any humans in the northern hemisphere to pay attention.
EDIT: while i was posting this A Team posted something along the same lines in the Melt Thread, just 1000x more classy and science-like.
if we talk about the arctic being ice free i say that each warm current has it's cold counterpart and that in one part of the arctic (one side if you prefer) there will always be a lot of ice.
if we talk about the arctic being ice free i say that each warm current has it's cold counterpart and that in one part of the arctic (one side if you prefer) there will always be a lot of ice.
You've said it before, and I asked: Is that some sort of natural law? That each warm current has it's cold counterpart? How and why?
To me this indicates a lack of understanding of how the big warm surface currents and the big cold bottom currents are tied together: The real counterpart of any warm surface current is a cold bottom current.
The image shows warm and cold currents in the North-Atlantic, both surface and deep. The warm currents are all on the surface, while the cold currents (with the exception of the narrow one running down the east coast of Greenland) are deep currents.
i tell you that none of us shall see an ice-free arctic in winter (arctic not north pole) and
you have another opinion which to proof false would take years work of studies and combine them into an excerpt. this is just too much and won't change the future anyways, hence i propose to leave it at that for the moment, it simply doesn't matter who is right and the future will tell what is right/wil happen.
enjoy further
i tell you that none of us shall see an ice-free arctic in winter (arctic not north pole) and
you have another opinion which to proof false would take years work of studies and combine them into an excerpt. this is just too much and won't change the future anyways, hence i propose to leave it at that for the moment, it simply doesn't matter who is right and the future will tell what is right/wil happen.
enjoy further
If I were to exclude certain areas, most notably the Hudson, would you still make that claim?
Suppose I posit that everywhere that is not very close to a cold continent will melt out soon (5 years) and stay melted out in the winter? What would you say about that?
I agree that the Arctic won’t be completely ice free year round anytime soon, but it will eventually happen, we are taking the climate out of ice age to hothouse
The central arctic basin will not be ice-free in winter for at least some centuries, IMHO.
Take a look at the behavior of peripheral seas like the Chukchi and Bering, over time their ice-free season grows longer, but it's a very slow process and they still freeze over in winter. The Bering sea is very stormy, adjacent to the warm pacific, lies at only around 60 deg N, and still partially freezes over. So don't expect the north pole to stay ice-free year-round in your lifetime.
if we talk about the arctic being ice free i say that each warm current has it's cold counterpart and that in one part of the arctic (one side if you prefer) there will always be a lot of ice.
You've said it before, and I asked: Is that some sort of natural law? That each warm current has it's cold counterpart? How and why?
To me this indicates a lack of understanding of how the big warm surface currents and the big cold bottom currents are tied together: The real counterpart of any warm surface current is a cold bottom current.
The image shows warm and cold currents in the North-Atlantic, both surface and deep. The warm currents are all on the surface, while the cold currents (with the exception of the narrow one running down the east coast of Greenland) are deep currents.
now i'd have to post a book to counter your statements, we'd have to go into density, salinity, when warm currents start to drop to the sea-floor to return south etc. but there are cold currents on the surface for sure, humbolt and many others, so the "all" is not correct and more time i'm not willing to spend on this topic. we can agree that we disagree and see what happens.
i tell you that none of us shall see an ice-free arctic in winter (arctic not north pole) and
you have another opinion which to proof false would take years work of studies and combine them into an excerpt. this is just too much and won't change the future anyways, hence i propose to leave it at that for the moment, it simply doesn't matter who is right and the future will tell what is right/wil happen.
enjoy further
I agree that the Arctic won’t be completely ice free year round anytime soon, but it will eventually happen, we are taking the climate out of ice age to hothouse
I agree that the Arctic won’t be completely ice free year round anytime soon, but it will eventually happen, we are taking the climate out of ice age to hothouse
What is eventually? If its 200 years why is everyone fear-mongering on the subject ? The failed predictions of the past is one of the main reasons people are still debating AGW. Saying the arctic will be ice free in 50,30,20,10 years, sea level rise will disappear islands and roads on the coast will be under water and so many other predictions have failed.I agree that most are made by Politicians, celebrities and media (and some scientists looking for fame). Besides climate you can add in failed predictions on world famine,peak oil,population bomb and so many more. 200 years is a long time. Who knows what humanity can achieve in that time frame.
snip..
What is eventually? I..snip
Eventually is following trends.
90+ percent of additional heat trapped by increasing CO2 concentrations in the atmosphere is going into long-term storage in the oceans.
Does this not suggest that over time warm currents get warmer and cold currents less cold?
And that in turn is not good news for winter sea ice ?
as to currents (cold and warm) if the tone of that guy (not the quoted) get's slightly more condescending without reason i'll opt out, don't need to deal with things like that, one meeting in person would take care of that but it won't happen.
hat changes only if someone, who is not, thinks he can play extra smart just because this place is in his mother tongue and not in another language which many of those intolerant players don't even speak. now one can ask how do i know about the "he is not" that's very simple, a wise or at least fair person would never ever attack that way in a discussion that is case oriented, just because the reasoning and/or opinion does not fit his own and without being totally off.
So it's the personal attack now, along with a threat of bodily harm? How can you expect to make claims and not having to defend them, and instead start attacking and threatening people?
an see from your musings that you have essentially accepted this point.
snip..
What is eventually? I..snip
Eventually is following trends.
Too cryptic.
Everyone here follows trends- and are giving different answers to the poll.
So it's the personal attack now, along with a threat of bodily harm? How can you expect to make claims and not having to defend them, and instead start attacking and threatening people?
an see from your musings that you have essentially accepted this point.
wich bodily harm?
if you refer to the personal meeting ? where did i mention any physical exchange of energies ?
I agree that the Arctic won’t be completely ice free year round anytime soon, but it will eventually happen, we are taking the climate out of ice age to hothouse
What is eventually? If its 200 years why is everyone fear-mongering on the subject ?
The cold from land is no match for heat built up in water. Those -60C winds will quickly warm to around freezing if the heat is there in the water to support it. You simply won't see -30C in the CAB anymore if the water has a chance to soak up enough heat during the summer. It's not like the Hudson Bay, which is shallow, and can't build up much heat, and which will probably have ice in the winter until maybe after 2100. The ESS is shallow too, so I wouldn't be surprised to continue to see fast ice form there for many many decades in the winter. But I wouldn't expect this ice to go much farther than the continental shelf once the CAB gets a few ice-free summers from May onwards, and gets to warm up to 15C by each September. Heck, I wouldn't be surprised if it became possible to comfortably swim in the Arctic Ocean in some places in a few decades!
Heck, I wouldn't be surprised if it became possible to comfortably swim in the Arctic Ocean in some places in a few decades!Too bad Barentz is nowadays counted as Atlantic also in the north so my legs haven't again been soaked in the Arctic ocean.
I took this image from Nat Geographic edition Jan this year.
Ive seen many projections like this showing the likely last areas to retain summer ice. But given the recent lift off from Cape Morris-Jessup, the lack of ice off Eastern Greenland and northern advancement of warm salty Atlantic water, I wonder have the models got it all wrong and the last preserve of ice will be a lot further west than northern Greenland.
I guess in winter we will still see ice near the coast, but it will get smaller and smaller and float away a lot of times - of course depending on wind conditions etc
It is time for the monthly update of my extrapolation when the extent [Extent], volume [Volumen] and thickness [Dicke] will reach zero. The extrapolation occured linearly and by a logarithmic function; the latter one constantly resulting in earlier times. See attached table.
My answers to your questions and remarks:
1. Volume (and, in part, thickness) reduces faster than extent, therefore the non-linearity of the volume data is more expressed than the extent. This leads to extrapolation results with bigger differences between log and lin evaluation. For the winter and spring season the extent differences from year to year were slower in the 80s and 90s and have increased in the 00s but reduced in the 10s. This leads to the effect that the linear evaluation reaches zero a few years earlier than the log fit.
2. I used the log function in addition to the linear because the deviation is slightly smaller in the log function. A quadratic extrapolation delivers almost the same results than the log evaluation.
3. I have no expertise in Gompertz fits therefore I leave this to those who know how to deal with them correctly. But I confess that "Gompertz type fitted curves" look more closer to the volume data than linear, log or quadratic fits.
Generally: Extrapolations into the far future are scientifically nonsense. No-one knows which effect the first BOE in early autumn will have on the extent of the following months and years. With increasing GHG concentrations and changing ocean currents new mechanisms (at least new rates) in melting and re-freezing will be put into place.
I did this evaluation for myself just to know whether - on the basis of a continuation of the trend of the last 40 years - it will take decades, centuries or millenia to reach zero and I decided to share this information with you.
I believe (and correct me if I am wrong) that this exercise is just curve fitting to the best possible line. What we lack (me included) is an explanation as to why any particular fit should be chosen. Oftentimes, a linear fit can approximate a particular data curve over a specified range. As the data approaches zero, I would expect this to fail, although in which direction is debatable. In an unknown situation, oftentimes a moving average can best define the trend, as it incorporates recent data, without bias. Not that it is any more accurate, but it tends to smooth out the data, removing variations which may mislead the eye. Lastly, extrapolated beyond known parameters is always highly speculative, as we do not know how that affects the environment. In short, it is a guess. But we strive to make it the most educated best possible, and your guess may be different than mine, depending on which parameters we each feel might predominate in a future scenario.
The real value to look at is the volume. If you imagine a block of ice 1km*1km wide and 1 m thick, melting on its edges, say 1m/year, will almost not change its area and you need 500 years until it is gone. But if you melt 10 cm/year (only 10% of the edges' value) from below at the same time, it only needs 10 years to be completely gone. This is the "secret" behind the diverge of the data.
Well, ice conducts heat like any solids.The real value to look at is the volume. If you imagine a block of ice 1km*1km wide and 1 m thick, melting on its edges, say 1m/year, will almost not change its area and you need 500 years until it is gone. But if you melt 10 cm/year (only 10% of the edges' value) from below at the same time, it only needs 10 years to be completely gone. This is the "secret" behind the diverge of the data.
Not sure I agree with this logic. Melting is really only occurring in two dimensions; above from sunlight and below from sea water. Hence, extent seems to better reflect real world conditions.
My explanation was not to describe exactly what happens when an ice floe on sea water is melting but to illustrate the much more important volume decrease in comparison to an extent (or area) decrease, when it comes to define which one of the three measures (area/extent, volume or thickness) plays the major role in the time until the first BOE occurs.
Extent is deceptive. If the arctic has a typical thickness of 2.5m at max, and each year's melt is 2m, what does extent tell you? That all is well. When typical thickness drops to 2.3m at max, and annual melt increases to 2.1m, extent still looks almost fine. But when thickness at max drops to 2.2m and annual melt to 2.3m, you get a BOE all of a sudden.
Extent is showing a trend because at the edges the ice is thinner and annual melt larger than at the heart of the pack. But volume trend is much more indicative.
oren has just explained the possibility of a "surprising" BOE. His figures are completely valid, independent how thick the ice is and independent how high the melting rate is. It is just an example.Extent is deceptive. If the arctic has a typical thickness of 2.5m at max, and each year's melt is 2m, what does extent tell you? That all is well. When typical thickness drops to 2.3m at max, and annual melt increases to 2.1m, extent still looks almost fine. But when thickness at max drops to 2.2m and annual melt to 2.3m, you get a BOE all of a sudden.
Extent is showing a trend because at the edges the ice is thinner and annual melt larger than at the heart of the pack. But volume trend is much more indicative.
I thick you are misrepresenting the situation. The thickness varies across the Arctic, and does not melt uniformly. What you are describing is a small inland lake, which will freeze overnight in the winter, and then slowly melt in the spring, until one day it all disappears.
oren has just explained the possibility of a "surprising" BOE. His figures are completely valid, independent how thick the ice is and independent how high the melting rate is. It is just an example.Extent is deceptive. If the arctic has a typical thickness of 2.5m at max, and each year's melt is 2m, what does extent tell you? That all is well. When typical thickness drops to 2.3m at max, and annual melt increases to 2.1m, extent still looks almost fine. But when thickness at max drops to 2.2m and annual melt to 2.3m, you get a BOE all of a sudden.
Extent is showing a trend because at the edges the ice is thinner and annual melt larger than at the heart of the pack. But volume trend is much more indicative.
I thick you are misrepresenting the situation. The thickness varies across the Arctic, and does not melt uniformly. What you are describing is a small inland lake, which will freeze overnight in the winter, and then slowly melt in the spring, until one day it all disappears.
I am very convinced that volume is the measure that has to be looked at if you want to extrapolate to the first BOE. oren's example shows that the extrapolation of area or extent gives much too high values, because if the ice gets very thin, then the floes' area will reduce with an accelerating rate. This rate will once meet the volume reduction rate in the graph close before the BOE will take place.
You are convinced that a BOE will occur when the ice gets very thin, the perhaps you should choose thickness as the measure to be looked at if you want to extrapolate. The only reason that the two-dimensional measures give too high a value, is you think it should be lower. I think that is a rather biased reason. But, to each his own.That's an odd argument if you ask me. The thickness is estimated by dividing area or extent by volume. There is a lot of thin ice at the start of the season and a little bit of thick ice regardless of the overall extent. As volume and extent decline the average thickness doesn't vary much. Thickness is probably a worse indicator than extent or area. Volume seems a much more likely measure because it measures the amount of ice lost each year.
which proves the point: extrapolation does not work. It doesn't work, beacuse it is a nonlinear system, and melting the shelf is not the same as melting the central pack. Therefore extrapolations are rather a waste of time.
which proves the point: extrapolation does not work. It doesn't work, beacuse it is a nonlinear system, and melting the shelf is not the same as melting the central pack. Therefore extrapolations are rather a waste of time.
Seems a bit sweeping to me. ...
You pick out two reasons: non linear and central vs shelf. Certainly it is much easier to extrapolate with a linear system and I also agree re central vs shelf. But I would suggest that there are other reasons and maybe the two you picked alone wouldn't automatically mean that extrapolations will always fail.
Yay Archimid! That looks like if the system change of 2010-2014 is the real change, and all other measurements are in error ice will never go away! Nice example of real problems in selecting anything other than a linear function for an extrapolation.
The current three cell system acts as a block preventing that. With the loss of the three cell system, the circulation will likely look more like what we see on Venus.
Conditions there are so radically different from those on Earth, that we likely cannot learn too much from Venus as an exemplar. It does though give us a crude framework to consider.
Sam
Curve fitting can sometimes be an exercise in futility. It looks nice, but does it describe the true situation. Hard to imagine maximum ice volume approaching zero in an environment that is 20C below freezing.
Curve fitting can sometimes be an exercise in futility. It looks nice, but does it describe the true situation. Hard to imagine maximum ice volume approaching zero in an environment that is 20C below freezing.
You say this, yet the Arctic has been ice free multiple times before
Curve fitting can sometimes be an exercise in futility. It looks nice, but does it describe the true situation. Hard to imagine maximum ice volume approaching zero in an environment that is 20C below freezing.
You say this, yet the Arctic has been ice free multiple times before
Yes, during those times when the temperature was warming, preventing freezing. Simple physics.
...snip
Not at all. Should the Arctic temperature increase another 5C, then complete melting of the ice is certainly possible. That is the estimated temperature the last time the Arctic was ice-free.
Should the Arctic temperature increase another 5C, then complete melting of the ice is certainly possible. That is the estimated temperature the last time the Arctic was ice-free.
Volume is the key metric, as it is the primary expression of over-all heat exchange and total enthalpy in the system.You are convinced that a BOE will occur when the ice gets very thin, the perhaps you should choose thickness as the measure to be looked at if you want to extrapolate. The only reason that the two-dimensional measures give too high a value, is you think it should be lower. I think that is a rather biased reason. But, to each his own.That's an odd argument if you ask me. The thickness is estimated by dividing area or extent by volume. There is a lot of thin ice at the start of the season and a little bit of thick ice regardless of the overall extent. As volume and extent decline the average thickness doesn't vary much. Thickness is probably a worse indicator than extent or area. Volume seems a much more likely measure because it measures the amount of ice lost each year.
Volume declines based on the difference between the ice formed in the freezing season and the ice melting in the melting season. This has meant an average loss of about about 320 km^3 per year since 1988 but about 500 Km^3 per year since 2000 this appears to be increasing exponentially as warmer waters move into the Arctic. With only 5000 Km^3 at minimum this year it seems highly likely that within 10 years we will see a BOE in September. Extrapolating from extent, thickness or area gives a much later date.
You are convinced that a BOE will occur when the ice gets very thin, the perhaps you should choose thickness as the measure to be looked at if you want to extrapolate. The only reason that the two-dimensional measures give too high a value, is you think it should be lower. I think that is a rather biased reason. But, to each his own.That's an odd argument if you ask me. The thickness is estimated by dividing area or extent by volume. There is a lot of thin ice at the start of the season and a little bit of thick ice regardless of the overall extent. As volume and extent decline the average thickness doesn't vary much. Thickness is probably a worse indicator than extent or area. Volume seems a much more likely measure because it measures the amount of ice lost each year.
Volume declines based on the difference between the ice formed in the freezing season and the ice melting in the melting season. This has meant an average loss of about about 320 km^3 per year since 1988 but about 500 Km^3 per year since 2000 this appears to be increasing exponentially as warmer waters move into the Arctic. With only 5000 Km^3 at minimum this year it seems highly likely that within 10 years we will see a BOE in September. Extrapolating from extent, thickness or area gives a much later date.
volume will always show a faster rate of decline than either area or thickness, but will slow down as the other parameters catch up.I'm not sure this is always true, but I'm not a thermodynamics anything (not an expert nor even particularly knowledgeable). If a significant cause of ice melt is bottom melt (which will likely increase as thickness decreases, as solar input into this process increases with ice thinness), then declining thickness will accelerate as zero volume approaches, while area remains fairly unchanged. If area decreases 'at all', it might be a 'fact' that volume will decrease at a lower rate than does thickness (although faster than the area decline). But I think this doesn't require volume declines to actually "slow down".
Quotevolume will always show a faster rate of decline than either area or thickness, but will slow down as the other parameters catch up.I'm not sure this is always true, but I'm not a thermodynamics anything (not an expert nor even particularly knowledgeable). If a significant cause of ice melt is bottom melt (which will likely increase as thickness decreases, as solar input into this process increases with ice thinness), then declining thickness will accelerate as zero volume approaches, while area remains fairly unchanged. If area decreases 'at all', it might be a 'fact' that volume will decrease at a lower rate than does thickness (although faster than the area decline). But I think this doesn't require volume declines to actually "slow down".
I fully expect the ice melt rate to increase as the ice volume nears zero.
Except that doesn't seem to be what's happening:
snip...
So perhaps intuition, and analogizing the Arctic to ice cubes in a drinking glass, aren't all that helpful? Reality sure looks more like one of crandles's Gompertz curves.
The key point you are missing is that the thickness is an average measure over the entire ice cap. The area that is less than 20cm thick at maximum is 20 - 30 times greater than the are that is 2 m thick for the same volume. The simple formula V=A*T only works for a single cell.Quotevolume will always show a faster rate of decline than either area or thickness, but will slow down as the other parameters catch up.I'm not sure this is always true, but I'm not a thermodynamics anything (not an expert nor even particularly knowledgeable). If a significant cause of ice melt is bottom melt (which will likely increase as thickness decreases, as solar input into this process increases with ice thinness), then declining thickness will accelerate as zero volume approaches, while area remains fairly unchanged. If area decreases 'at all', it might be a 'fact' that volume will decrease at a lower rate than does thickness (although faster than the area decline). But I think this doesn't require volume declines to actually "slow down".
It is a case of simple mathematics. The current minimum sea ice extent is ~60% of the extent measured in 1980. The minimum volume is ~30% of 1980. The thickness is ~50% of 1980. Volume is just a product of these two; and since both are decreasing, the volume must decrease faster. As extent and thickness decrease, the volume loss will slow because there is less volume to lose.
This is different from the typical ice cube in a glass experiment, whereby all sides melt equally. The large disproportionate dimensions leads to a difference in the physical melting properties. The larger extent (or area) dominates the melting characteristic.
If one were to assume that volume is the key parameter, and volume continues to decrease at its current rate, then the decline in thickness would need to double and the decline in extent more than triple, so that all three parameters reach zero simultaneously. That is not what we are experiencing currently.
The key point you are missing is that the thickness is an average measure over the entire ice cap. The area that is less than 20cm thick at maximum is 20 - 30 times greater than the are that is 2 m thick for the same volume. The simple formula V=A*T only works for a single cell.Quotevolume will always show a faster rate of decline than either area or thickness, but will slow down as the other parameters catch up.I'm not sure this is always true, but I'm not a thermodynamics anything (not an expert nor even particularly knowledgeable). If a significant cause of ice melt is bottom melt (which will likely increase as thickness decreases, as solar input into this process increases with ice thinness), then declining thickness will accelerate as zero volume approaches, while area remains fairly unchanged. If area decreases 'at all', it might be a 'fact' that volume will decrease at a lower rate than does thickness (although faster than the area decline). But I think this doesn't require volume declines to actually "slow down".
It is a case of simple mathematics. The current minimum sea ice extent is ~60% of the extent measured in 1980. The minimum volume is ~30% of 1980. The thickness is ~50% of 1980. Volume is just a product of these two; and since both are decreasing, the volume must decrease faster. As extent and thickness decrease, the volume loss will slow because there is less volume to lose.
This is different from the typical ice cube in a glass experiment, whereby all sides melt equally. The large disproportionate dimensions leads to a difference in the physical melting properties. The larger extent (or area) dominates the melting characteristic.
If one were to assume that volume is the key parameter, and volume continues to decrease at its current rate, then the decline in thickness would need to double and the decline in extent more than triple, so that all three parameters reach zero simultaneously. That is not what we are experiencing currently.
Over the entire cap the AverageThickness = sum(( T * N ) / Total(N)) for all thicknesses where N is the number of cells of a given thickness. As the ice melts the ratios between the various N's doesn't change much so the average thickness doesn't change either.
Simple example; there are 100 cells at thickness 0.1m and 10 at thickness 1m; after massive melting the number of cells has reduced to 10 at 0.1m and 1 at 1m. The ratio hasn't changed and the average thickness hasn't changed despite area declining by 90%.
Just a question for us all.
We already have seas that melt out completely (like Hudson or Kara). Would these seas be an example for a BOE? And has anyone ever monitored the rates of volume, thickness and area decline close before the end and compared these rates with the rates at about 30, 50, 70 % of ice coverage? This analysis (also the relation of the rates) could help to answer the questions that arose in this thread.
Just a question for us all.
We already have seas that melt out completely (like Hudson or Kara). Would these seas be an example for a BOE? And has anyone ever monitored the rates of volume, thickness and area decline close before the end and compared these rates with the rates at about 30, 50, 70 % of ice coverage? This analysis (also the relation of the rates) could help to answer the questions that arose in this thread.
We already have seas that melt out completely (like Hudson or Kara). Would these seas be an example for a BOE?
Thanks Oren. Here at forum, it's easy to pick up some alarmistic views as people present their pet theories. It's easy to forget main stream science has some very good arguments too.
Thank you oren for this animation.Apologies for the delay in responding.
I am willing to investigate the area/extent, thickness and volume changes over the years and to look at "BOE" predictions derived from area/extent, thickness and volume. Can anyone send me the .xls or .csv files of area/extent, thickness and/or volume for Kara, Chukchi and Hudson Sea? Would be nice, thanks in advance.
ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/Sea_Ice_Index_Regional_Daily_Data_G02135_v3.0.xlsx
That 2070 timeframe looks about right.
impatient observers who want to witness ice-free
unfortunately some impatient observers who want to witness ice-free under all circumstances or seek headlines will come up with all kinds of arbitrary values that should serve as "ice-free"Heh, the Arctic Ocean is ~14,000,000 km² and the origin of that number is:
the most common of such numbers at the moment is < 1'000'000 km2 of extent which i find ridiculous
Towards a rain-dominated Arctic
Richard Bintanja and Olivier Andry
Royal Netherlands Meteorological Institute (KNMI), De Bilt, Netherlands (bintanja@knmi.nl)
Current climate models project a strong increase in Arctic precipitation over the coming century, which has been attributed primarily to enhanced surface evaporation associated with sea-ice retreat. Since the Arctic is still quite cold, especially in winter, it is often (implicitly) assumed that the additional precipitation will fall mostly as snow.
However, very little is known about future changes in rain/snow distribution in the Arctic, notwithstanding the importance for hydrology and biology. Here we use 37 state-of-the-art climate models in standardised twenty-firstcentury (2006–2100) simulations to show that 70◦ – 90◦N average annual Arctic snowfall will actually decrease, despite the strong increase in precipitation, and that most of the additional precipitation in the future (2091–2100) will fall as rain. In fact, rain is even projected to become the dominant form of precipitation in the Arctic
region. This is because Arctic atmospheric warming causes a greater fraction of snowfall to melt before it reaches the surface, in particular over the North Atlantic and the Barents Sea. The reduction in Arctic snowfall is most pronounced during summer and autumn when temperatures are close to the melting point, but also winter rainfall is found to intensify considerably. Projected (seasonal) trends in rain/snowfall will heavily impact Arctic hydrology (e.g. river discharge, permafrost melt), climatology (e.g. snow, sea ice albedo and melt) and ecology (e.g. water and food availability).
Extract from a post by AbruptSLR.
https://forum.arctic-sea-ice.net/index.php/topic,2205.msg182527.html#msg182527
Goodbye snow, hullo rain. That would tend to slow down winter sea ice formation?
(And not do bbr's hypothesis a lot of good).QuoteTowards a rain-dominated Arctic
Richard Bintanja and Olivier Andry
Royal Netherlands Meteorological Institute (KNMI), De Bilt, Netherlands (bintanja@knmi.nl)
Current climate models project a strong increase in Arctic precipitation over the coming century, which has been attributed primarily to enhanced surface evaporation associated with sea-ice retreat. Since the Arctic is still quite cold, especially in winter, it is often (implicitly) assumed that the additional precipitation will fall mostly as snow.
However, very little is known about future changes in rain/snow distribution in the Arctic, notwithstanding the importance for hydrology and biology. Here we use 37 state-of-the-art climate models in standardised twenty-firstcentury (2006–2100) simulations to show that 70◦ – 90◦N average annual Arctic snowfall will actually decrease, despite the strong increase in precipitation, and that most of the additional precipitation in the future (2091–2100) will fall as rain. In fact, rain is even projected to become the dominant form of precipitation in the Arctic
region. This is because Arctic atmospheric warming causes a greater fraction of snowfall to melt before it reaches the surface, in particular over the North Atlantic and the Barents Sea. The reduction in Arctic snowfall is most pronounced during summer and autumn when temperatures are close to the melting point, but also winter rainfall is found to intensify considerably. Projected (seasonal) trends in rain/snowfall will heavily impact Arctic hydrology (e.g. river discharge, permafrost melt), climatology (e.g. snow, sea ice albedo and melt) and ecology (e.g. water and food availability).
Stephan, can you extrapolate to 1M km2 of extent as well? The "nearly ice free" criterion.Here is the table (the right one with extrapolation to 1M).
By the way, I believe that the above is the explanation for the "stall" since 2007: the shallow parts have entered a new era (system change) but the Central Arctic has not. When it will do so, I do not know. It could be next year (I very much doubt it ) but it also might stay like that for another 30 yearsPlease check my 5 year averages I posted yesterday in the "latest PIOMAS" thread. There is no stall, only the volume has not further decreased in the years 2014-2018 compared to 2009-2013. (Re: Latest PIOMAS update (December)
There is no stall, only the volume has not further decreased
Maybe the "stall" is a statistical construct. Or maybe (a heresy to say on this site it seems) after the periphery melt out relatively quickly, the Central Arctic has different characteristics and will be a much harder nut to crack. In my opinion the "stall" is due to that the "easy" ice is gone and it is more difficult to melt the central parts. That is why you can not extrapolate from the past few years. The Central Arctic will be gone for (almost) sure but it is hard to model when in my view. Let me attach a picture how I see this whole process...
Abstract
Many climate models, including the the Community Earth System Model Large Ensemble (CESM‐LE), predict future rapid sea ice declines in the Arctic linked with anomalous northward Ocean Heat Transport (OHT). Using CESM‐LE, we find that the partitioning of the poleward OHT between the different Arctic gates (Barents Sea Opening (BSO), Bering Strait and Fram Strait) is key to this link with the rapid declines. 64 of the 79 rapid declines in CESM‐LE are correlated with the anomalous OHT through one of the gates. Rapid declines that happen earlier in the simulations when the sea ice covers the continental shelves are correlated with anomalous OHT. The interaction between OHT and sea ice happens mainly over continental shelves since most rapid declines are correlated with the BSO or Bering Strait OHTs and only a few with the Fram Strait OHT (often also correlated with BSO or Bering Strait OHTs). In most rapid rapid declines not correlated with OHT, the September Sea Ice Extent (SIE) prior to the decline is smaller than the area covered by the deep basins. Those are associated with surface heat flux since the ice‐atmosphere heat fluxes are more strongly correlated with the sea ice concentrations over the deep basins than the ice‐ocean heat fluxes. Our results suggest that OHTs are causing rapid sea ice declines when the SIE is large enough to cover the continental shelves and that the atmosphere is the main driver when the initial SIE is located only over the deep basins.
Plain Language Summary
A significant decrease in the minimum sea ice extent has been observed since the beginning of the satellite era in the late seventies. Several climate models simulate drastically different future evolution of the minimum sea ice extent. In this study, we use output diagnostics from the Community Earth System Model Large Ensemble to verify if the pathway of ocean heat transport entering the Arctic has an impact on the presence or absence of rapid sea ice declines. We find that the interaction between ocean heat transport and sea ice happens mainly over the shallow continental shelves. There, ocean heat transport can contribute to the melting of the sea ice. This melting is afterward enhance by positive feedbacks, such as the ice‐albedo feedback, and can lead to a rapid decline of the Arctic sea ice cover. In the central Arctic, the sea ice is more sensitive to atmospheric heat than to ocean heat.
Maybe the "stall" is a statistical construct. Or maybe (a heresy to say on this site it seems) after the periphery melt out relatively quickly, the Central Arctic has different characteristics and will be a much harder nut to crack. In my opinion the "stall" is due to that the "easy" ice is gone and it is more difficult to melt the central parts. That is why you can not extrapolate from the past few years. The Central Arctic will be gone for (almost) sure but it is hard to model when in my view. Let me attach a picture how I see this whole process...
...the point is that the seeming stall could last only a very few but even a good many years as well
[/quote]Maybe the "stall" is a statistical construct. Or maybe (a heresy to say on this site it seems) after the periphery melt out relatively quickly, the Central Arctic has different characteristics and will be a much harder nut to crack. In my opinion the "stall" is due to that the "easy" ice is gone and it is more difficult to melt the central parts.
There is a new paper that I think supports your contention. Basically it says that increased ocean heat transport (OHT) affects the Arctic seas over the continental shelves while it is the atmosphere that drives SIE in the central arctic (over the deep ocean). [/size]
Maybe the "stall" is a statistical construct. Or maybe (a heresy to say on this site it seems) after the periphery melt out relatively quickly, the Central Arctic has different characteristics and will be a much harder nut to crack. In my opinion the "stall" is due to that the "easy" ice is gone and it is more difficult to melt the central parts.
There is a new paper that I think supports your contention. Basically it says that increased ocean heat transport (OHT) affects the Arctic seas over the continental shelves while it is the atmosphere that drives SIE in the central arctic (over the deep ocean). [/size]
Great points everone! Much to think about. I have not much else to add. The trillion dollar question to me is: can and will mixing occur in the Central Arctic? If not, then export will probably be a slow way to get rid of all the ice and make the Central Arctic ice free.
Please note that this is not a forecast but a trend!Great table Stephan!
See attached table.
Please note that this is not a forecast but a trend!Great table Stephan!
See attached table.
Of course (as my signature says), I believe that volumen has the real trend, extent and thickness are just partial views of reality. Even so, I think that some negative feedbacks will start to slow down the volume melting trend. So I thinking that we will have a BOE on September until 2040+.
Maybe it is just a good wish, and positive feedbacks will rule the near future.
This is largely a two-dimensional system.
I would state that volume is the aberration here.
QuoteThis is largely a two-dimensional system.
Really?QuoteI would state that volume is the aberration here.
There is no aberration here. Area, volume and thickness are all valid variables, dependent on each other, and they all reveal different aspects of the ice. It would serve us well to completely understand how they change relative to each other and relative to the other thousand variables out there.
QuoteThis is largely a two-dimensional system.
Really?QuoteI would state that volume is the aberration here.
There is no aberration here. Area, volume and thickness are all valid variables, dependent on each other, and they all reveal different aspects of the ice. It would serve us well to completely understand how they change relative to each other and relative to the other thousand variables out there.
Considering that the area or extent varies from 4 to 15 square km annually, while the thickness varies from 2 to 3 meters, the thickness is no more than 0.1% of each of the other two dimension. The thickness is also an estimated value based on models, compared to the other measured values. Physically, changes in area have a dramatically greater effect on albedo than changes in thickness. Unless this small dimension can be shown to influence the sea ice to much greater degree than the others, I tend to ignore its effect.
I am still wondering how much of the recent strong extent gains and losses is from freezing / melting and how much from existing ice being spread out or pushed together due to winds and waves.Quote
I think one needs to consider area and volume to better understand this system. Though area/extent and volume are related they tell you different things.
QuoteThis is largely a two-dimensional system.
Really?QuoteI would state that volume is the aberration here.
There is no aberration here. Area, volume and thickness are all valid variables, dependent on each other, and they all reveal different aspects of the ice. It would serve us well to completely understand how they change relative to each other and relative to the other thousand variables out there.
Considering that the area or extent varies from 4 to 15 square km annually, while the thickness varies from 2 to 3 meters, the thickness is no more than 0.1% of each of the other two dimension. The thickness is also an estimated value based on models, compared to the other measured values. Physically, changes in area have a dramatically greater effect on albedo than changes in thickness. Unless this small dimension can be shown to influence the sea ice to much greater degree than the others, I tend to ignore its effect.
The energy required to melt ice doesn't differentiate between area and volume, however, area cannot decrease until all of the thickness below the surface has been melted, therefore volume is initially more responsive to increases in energy than area. As volume declines more energy is available to both melt area, and restrict its growth (ignoring potential short term negative feedbacks from melt water).
Seems pretty straight forward to me, though, geography does matter.
This is largely a two-dimensional system,
This is largely a two-dimensional system,
it's about energy and how much energy is needed to melt how much ice is mostly about volume.
of course area plays a role when it comes to insolation and air-flow but nevertheless it's about how much energy is needed to melt a given amount of ice and "amount" is equivalent to volume.
This is largely a two-dimensional system,
it's about energy and how much energy is needed to melt how much ice is mostly about volume.
of course area plays a role when it comes to insolation and air-flow but nevertheless it's about how much energy is needed to melt a given amount of ice and "amount" is equivalent to volume.
And greater surface area absorbs more energy.
If 1980 was 2.6 m thick, and 2017 1.5 m thick, then the linear thickness loss rate is about 0.3 m per year. With 1.5 m remaining, then extrapolating a linear trend we find zero thickness in about 2068. But nothing in the Arctic is linear.If I go back to my table and define June 1st just as a 1:1 "mixture" of May and June, we'll end up with a BOE at around 2103 (log evaluation) and 2112 (lin evaluation), which shows that there is no big difference between these two ways of evaluation, which implies an acceptable assumption of linearity. Noone of us will have the chance to prove that unless BOE happens much earlier than around the start of the next century.
If 1980 was 2.6 m thick, and 2017 1.5 m thick, then the linear thickness loss rate is about [edit: 0.03] m per year. With 1.5 m remaining, then extrapolating a linear trend we find zero thickness in about 2068. But nothing in the Arctic is linear.I have three comments about this simplistic projection.
Who would have thought that the summer minimum would cease to drop over the last decade?
Who would have thought that the summer minimum would cease to drop over the last decade? Many recent publications have sought to explain this. I tend to agree that I will not live long enough to witness a BOE.
On extent, the ASI has not even able to break the 2007 record, not to mention the 2012 record. So, there are some people saying that 2012 is an outlier and even 2007 will be difficult to break. But I don’t like extent! Yes, it is important to measure the effect of the Arctic Ocean albedo. But to measure the ASI drop, I am convinced that we should use volume, even if it is harder to measure than extent.
So, what do I see on volume?
First, volume on 2007 has been broken several times. On volume, [September] 2007 is the ninth lowest on record! And even that September 2012 is still the lowest, the difference between 2012 with 2010-2011 and 2016-17 is not that big.
…
The 39.5% ice that we have on 2010-18, versus the 1979-2000 baseline, is climate change, not just one year, not weather change.
If 1980 was 2.6 m thick, and 2017 1.5 m thick, then the linear thickness loss rate is about [edit: 0.03] m per year. With 1.5 m remaining, then extrapolating a linear trend we find zero thickness in about 2068. But nothing in the Arctic is linear.I have three comments about this simplistic projection.
- Much of the larger 1980's thickness was associated with thick multi-year ice that has drifted out The Fram (mostly) over 30+ years and has been replaced with younger ice, which in turn is replaced with about the same age of young ice, so the future decline rate is likely to be less ("Slow Transition (https://forum.arctic-sea-ice.net/index.php/topic,933.msg32299.html#msg32299)" thread).
- I expect Arctic ice to crumple to nothingness after it gets to 10 or 20 cm thick, due to waves (https://forum.arctic-sea-ice.net/index.php/topic,1222.msg49706.html#msg49706), etc., so the final decline may be fast.
- I used to have an opinion about when 'ice freedom' would occur; now I don't.
Speaking to point 2 I think volume will be the driver. I think the I think the tip over point will occur at somewhere around 2000KM3 volume. When the Arctic ice reaches that threshold I think the other mechanical forces we are thinking about will come into play and will overwhelm the remaining extent very quickly.If 1980 was 2.6 m thick, and 2017 1.5 m thick, then the linear thickness loss rate is about [edit: 0.03] m per year. With 1.5 m remaining, then extrapolating a linear trend we find zero thickness in about 2068. But nothing in the Arctic is linear.I have three comments about this simplistic projection.
- Much of the larger 1980's thickness was associated with thick multi-year ice that has drifted out The Fram (mostly) over 30+ years and has been replaced with younger ice, which in turn is replaced with about the same age of young ice, so the future decline rate is likely to be less ("Slow Transition (https://forum.arctic-sea-ice.net/index.php/topic,933.msg32299.html#msg32299)" thread).
- I expect Arctic ice to crumple to nothingness after it gets to 10 or 20 cm thick, due to waves (https://forum.arctic-sea-ice.net/index.php/topic,1222.msg49706.html#msg49706), etc., so the final decline may be fast.
- I used to have an opinion about when 'ice freedom' would occur; now I don't.
I've no idea on point 1, but I agree totally with points 2 and 3. It's very unclear when the BOE will happen, but when it does the end will come suddenly.
Why aren't people considering the ice to be more like a wedge as the minimum is approached with the thickest parts nearest Greenland/CAA? And there are, in any year, always some bits going below that critical thickness?
Is there any reason for thinking that a lot of area will suddenly go below some critical threshold whether between 10 and 20cm or some other particular thickness?
Is it just because that doesn't fit with personal beliefs that when the end comes it will happen suddenly?
Can you see how this sounds like, I want this fast end collapse conclusion and therefore I am going to believe in this sudden collapse once it goes under a certain threshold rather than working with what we would expect to ultimately arrive at a conclusion?
Is there any reason for thinking that a lot of area will suddenly go below some critical threshold whether between 10 and 20cm or some other particular thickness?I don't *want* a fast collapse conclusion, Crandles. My understanding of the system dynamics tends to support that kind of event.
Why aren't people considering the ice to be more like a wedge as the minimum is approached with the thickest parts nearest Greenland/CAA? And there are, in any year, always some bits going below that critical thickness?
Is it just because that doesn't fit with personal beliefs that when the end comes it will happen suddenly? Can you see how this sounds like, I want this fast end collapse conclusion and therefore I am going to believe in this sudden collapse once it goes under a certain threshold rather than working with what we would expect to ultimately arrive at a conclusion?
If you have worked it the other way, considered the wedge as explained above and have reasons for dismissing it, then that is fine, you will be able to explain your reasoning as to why you reached that conclusion and won't find this post annoying. If you just find this post annoying then ....
Discussions of fast crashes when thickness gets below a given threshold always strike me as conflating two UTTERLY different things.(summarized: melting behavior and distribution)
<snippage>
Attached is the volume for the CAB only. <snippage>Nice chart, are they piomas numbers?
Attached is the volume for the CAB only. <snippage>Nice chart, are they piomas numbers?
Nice chart indeed.
The fact that a new lower max was set in early 2017 hints that the process is not really over, so I am not sure this is a balance. But certainly the CAB will be more resilient, with its consistent winter freezing and short melting season.
Sorry, don't see it in the data at all.
Sorry, don't see it in the data at all.
I know we focus in on the Basin but there is a big old world beyond that and since the Pacific naturals flip in 2014 I believe we are seeing the rates of warming increase up and beyond that seen through the 80's/90's?
Based on minimums 1979-2018 and linear regression, I calculated probabilities to get minimum below 2012 in 2019-2035 (blue dots). Also cumulative probability (red dots) and probability to get minimum below 2012 first time that year (green dots).
Or under-estimated.Based on minimums 1979-2018 and linear regression, I calculated probabilities to get minimum below 2012 in 2019-2035 (blue dots). Also cumulative probability (red dots) and probability to get minimum below 2012 first time that year (green dots).
Using linear regression for predictions in a non-linear system may not be the best. Hence, I think you have over-estimated the probabilities.
Based on minimums 1979-2018 and linear regression, I calculated probabilities to get minimum below 2012 in 2019-2035 (blue dots). Also cumulative probability (red dots) and probability to get minimum below 2012 first time that year (green dots).From linear regression of the Sep averages an area of 3,50 M km² will be reached around 2030.
Some years before a BOE becomes anything like normal, will we have to change the maps vis a vis where the Atlantic ends and the Arctic begins?
I can see an International Conference looming by about 2030 (or before?) ?
It seems maximum volume was reached in day 110. I will update the model that belongs to me for when the Arctic will go ice free every tic. That is, for every minimum and maximum volume I will update the trendlines and averages and combine them into an animation.The bottom trendline bothers me, for a specific reason; it's a proxy for the annual heat entering the Arctic.
I will do one assuming the minimum hit a new state in 2007 and another one using the whole satellite data set. Let me know what you think.
The bottom trendline bothers me, for a specific reason; it's a proxy for the annual heat entering the Arctic.
That isn't decreasing, *can't* decrease past a hard limit described by that total insolation + other heat inflows.
I'd be highly surprised if it really could drop below 17,000km3/year. I doubt it can remain consistently below 18,000km3/year.
That's the value I'm actually watching to determine when we hit "ice free".
The bottom trendline bothers me, for a specific reason; it's a proxy for the annual heat entering the Arctic.
That isn't decreasing, *can't* decrease past a hard limit described by that total insolation + other heat inflows.
I'd be highly surprised if it really could drop below 17,000km3/year. I doubt it can remain consistently below 18,000km3/year.
That's the value I'm actually watching to determine when we hit "ice free".
Alternatively, you could (more correctly?) argue it *can't* be above max volume.
However, if the ice shrinks to a smaller area then isn't it logical that the heat energy that the ice can gather from "total insolation + other heat inflows" is also likely to go down?
Same area but thinner and the energy gathered by the ice is likely to go up not stay steady or go down. We have had a lot of this as thick MYI disappeared. (~2000-2012?) We have reached the end of this rapid thinning and now we are getting more of the area shrinkage with volume.
So is a horizontal or straight line extrapolation appropriate?
Fair point. The graph referred to is showing ice volume change.Alternatively, you could (more correctly?) argue it *can't* be above max volume.
It can't go above max volume in terms of water volume. In term of heat it can certainly go past max negative heat.
QuoteSame area but thinner and the energy gathered by the ice is likely to go up not stay steady or go down. We have had a lot of this as thick MYI disappeared. (~2000-2012?) We have reached the end of this rapid thinning and now we are getting more of the area shrinkage with volume.
The graph showing losses for 2007-2018 already takes that mechanical feature of Arctic melt somewhat into account as it doesn't include the years when ice was significantly thicker. Even so, losses are greater now that the ice is thin than when the ice was thick.
For the Maximum volume a linear extrapolation works very well. For the minimum it doesn't. That's why I include two versions. One takes the satellite data set as the Arctic system, the other assumes there was a state change in 2007 and data before that is meaningless. Hopefully, we get to see how they change over time.
A less technical answer would be that linear extrapolation is what it is. It assumes that exactly what happened in the past will happen in the future. It is naive because it is a fact of life that things change. But it is insightful because it is also a fact of life that things tend to repeat.
I wasn't particularly referring to mechanical strength.
Thinner ice converts to open water more easily and that has albedo consequences meaning much more of the insolation is captured. Then if ice is nearby, currents are likely to move the heat to the ice. But if the ice is a long way away then then likelihood of that heat being transferred to the ice is much reduced.
Straight line is sensible when you expect the same physics to be in play or has shown to work well and there is no reason to expect change ....
I find it interesting that three people voted for next century or later, while a dozen voted for a year or two.
Just shows the wide breadth of opinions. I am really more surprised that so many thought the Arctic would be ice-free by this year.
Maybe KK thought this meant the average of the whole year. Dipping to me is though crossing the point at any time.Just shows the wide breadth of opinions. I am really more surprised that so many thought the Arctic would be ice-free by this year.
You speak as this year is already done. 2019 is still in the game, IMO.
Just shows the wide breadth of opinions. I am really more surprised that so many thought the Arctic would be ice-free by this year.
You speak as this year is already done. 2019 is still in the game, IMO.
I don't know.Just shows the wide breadth of opinions. I am really more surprised that so many thought the Arctic would be ice-free by this year.
You speak as this year is already done. 2019 is still in the game, IMO.
Of course it is. However, after a fast start to the melt season, the ice loss has slowed dramatically this year. The 30-day melt is one of the lowest in the satellite data (only six years have shown less). At this point in 2012, the ice melt was already taking off, and the aforementioned 2016 (which was lower on this date) also experienced large losses. The multiple reports of greater thickness this year, is not indicative of an ice-free minimum this year. Over the past dozen years, the trend in sea ice minima has been relatively flat. It would take an extraordinary event (much more than observed in 2012) to cross the point at any time (No, miki I was not talking about average the whole year). Until we start seeing lower minima, I think that the later decades are more likely.
In this highly interesting interview published on May 08, 2019, Wieslaw Maslowski talks with Guy McPherson about Arctic Ice. You might recall In 2012 Maslowski published a paper projecting the arctic would be ice free in 2016 + or - 3 years.
Yes, for some scientists to learn>snip>I commented the previous poster, just like you did I guess? It also stands in general.
Yes, for some scientists to learn: avoid dissemination of catastrophic alarmist results if they don't have an extremely solid basis. 10-year linear trends? WTF?
Many deniers nowadays are using to discredit AGW claims from the 80's that were based on worst case scenarios and that did not come to happen.
I find alarmist scientists absolutely reckless. Fattening career and fame with +3sigma claims as baseline. As reckless as denier scientists paid with gold by the Cato Institute
Fortunately most of scientists take a more humble, more rigorous approach, something that is seen by some in forums like this as "coward" "staying in an ivory tower" "irresponsible" "slow science supports deniers" etc etc
Yes, for some scientists to learn: avoid dissemination of catastrophic alarmist results if they don't have an extremely solid basis. 10-year linear trends? WTF?
Many deniers nowadays are using to discredit AGW claims from the 80's that were based on worst case scenarios and that did not come to happen.
Fattening career and fame with +3sigma claims as baseline. As reckless as denier scientists paid with gold by the Cato Institute
I find alarmist scientists absolutely reckless.
Fortunately most of scientists take a more humble, more rigorous approach, something that is seen by some in forums like this as "coward" "staying in an ivory tower" "irresponsible" "slow science supports deniers" etc etc
remember after 2005, how some had claimed that this would be the “new normal” for hurricanes, only to be followed by a prolonged lull in activity.
I Droughts and starvation appear to be another common meme, that has failed to materialize.
Although in the U.S., it has been replaced by flooding, as drought is at an all time low.
Slow climate change proponents are giving the world the wrong risk assessment.
In this highly interesting interview published on May 08, 2019, Wieslaw Maslowski talks with Guy McPherson about Arctic Ice. You might recall In 2012 Maslowski published a paper projecting the arctic would be ice free in 2016 + or - 3 years.
If this doesn't happen, we might conclude Maslowski didn't have enough info of the future weather, though his projection was valid for exponential decrease of ice. We might try to add up the drops in Antarctic in the recent three years to the Arctic decrease and see how little there would be ice in Arctic if all the decrease had happened up there. SH was projected to be spared of the faster effects of CC due the higher ocean proportion and the protective function of ACC back then.
Yes, after a prolonged lull, hurricane activity returned to near average levels, neither high (alarmist), nor low (denialist).
Droughts ebb and flow. After every drought, some alarmist proclaims they are getting worse. Historically, droughts have been much worse.
Recent flooding is no worse either.
Obviously, you are encouraging alarmist and further food for the denialist machine. What is so wrong with accurate portrayal of the climate?
The good scientist admits when he is wrong, acknowledges those who are right, learns from them, and moves on.
I normally avoid watching videos of people talking, I prefer to better utilize my time reading, I find it to be much quicker and less biased. Stuff by Guy M I have read in the past led me to the conclusion that he is an unscientific alarmist, I actually prefer alarmists to lukewarmists but without science it's all just nonsense. But in any case, thanks for your summary of the video Tim. I did read it!
Any scientist who goes on the record that we are a decade away from human extinction will not be taken seriously by me. In fact, (adjusts tin foil cap) a purported scientist who goes on the record saying this does tremendous damage to real climate science, undermines the real threat that AGW presents to human civilization and causes me to suspect that he is actually being paid by the far right to do just this.
I’ll do, I’ll give you the rebuttal in 2030I normally avoid watching videos of people talking, I prefer to better utilize my time reading, I find it to be much quicker and less biased. Stuff by Guy M I have read in the past led me to the conclusion that he is an unscientific alarmist, I actually prefer alarmists to lukewarmists but without science it's all just nonsense. But in any case, thanks for your summary of the video Tim. I did read it!
Why don't you debunk Guy M scientifically - a lot of people would appreciate it.
I normally avoid watching videos of people talking, I prefer to better utilize my time reading, I find it to be much quicker and less biased. Stuff by Guy M I have read in the past led me to the conclusion that he is an unscientific alarmist, I actually prefer alarmists to lukewarmists but without science it's all just nonsense. But in any case, thanks for your summary of the video Tim. I did read it!
Consequently, he is hesitant to make any new ice-free projections.
I’ll do, I’ll give you the rebuttal in 2030I normally avoid watching videos of people talking, I prefer to better utilize my time reading, I find it to be much quicker and less biased. Stuff by Guy M I have read in the past led me to the conclusion that he is an unscientific alarmist, I actually prefer alarmists to lukewarmists but without science it's all just nonsense. But in any case, thanks for your summary of the video Tim. I did read it!
Why don't you debunk Guy M scientifically - a lot of people would appreciate it.
I’ll do, I’ll give you the rebuttal in 2030I normally avoid watching videos of people talking, I prefer to better utilize my time reading, I find it to be much quicker and less biased. Stuff by Guy M I have read in the past led me to the conclusion that he is an unscientific alarmist, I actually prefer alarmists to lukewarmists but without science it's all just nonsense. But in any case, thanks for your summary of the video Tim. I did read it!
Why don't you debunk Guy M scientifically - a lot of people would appreciate it.
I'll be dead by 2030.
Consequently, he is hesitant to make any new ice-free projections.
He's hesitant to make any specific ice-free projections, but he does think that it will be sooner than 2030.
Consequently, he is hesitant to make any new ice-free projections.
He's hesitant to make any specific ice-free projections, but he does think that it will be sooner than 2030.
No, he never said that. Only that it might.
Exactly! He said it might happen.
Exactly! He said it might happen.
Wow, srsly?
At the risk of beating a dead horse -
might1
/mīt/
3. used to express possibility or make a suggestion.
"this might be true"
I don't see why you contended with what I said initially. He does think it might happen before 2030 which also means sooner than 2030.
IMO, leaving the word 'might' out doesn't really change the meaning of the sentence. If 'might' was left out of what he said initially it would've been inferred anyway since he cannot absolutely know what will happen in the future.
[/
Initially, you said he thinks it will happen. Will indicates certainty. That is a big different from might, which [from your definition] indicates a possibility. Inferring from the video that he thinks it will happen is quite the stretch. Now, leave the horse alone.
I’ll do, I’ll give you the rebuttal in 2030I normally avoid watching videos of people talking, I prefer to better utilize my time reading, I find it to be much quicker and less biased. Stuff by Guy M I have read in the past led me to the conclusion that he is an unscientific alarmist, I actually prefer alarmists to lukewarmists but without science it's all just nonsense. But in any case, thanks for your summary of the video Tim. I did read it!
Why don't you debunk Guy M scientifically - a lot of people would appreciate it.
I'll be dead by 2030.
Why? Are you very elderly? Terminally ill? A uberdoomer?
Saying the arctic will go ice free before 2030 is just as valid as saying it won’t
In other words, you can be correct to say, "there's a 99% chance of rain tomorrow" even if it doesn't end up raining. The truth of your statement is based on past events (patterns) and not on what actually comes to pass.
This is what makes the IPCC, and for that matter, all model pathways, of limited value. Since our knowledge is extremely limited on these matters. It can be correct to consider something improbable even if it ends up happening. That is why ASLR is always talking about "fat tailed risk" and the precautionary principle.
...There is a danger that what you said conflates chaotic weather and fairly stable climate...
"Correct to say" is a fine term, and probabilities based on mathematics is accurate. If you flip a coin 10 times, there is a 99% probability that it will comes up heads at least once. However, there is a finite possibility that it will not. The outcome, in no way chances the odds, nor does it falsify them.
When talking about the weather or climate, the probabilities are a bit more nebulous. When a forecaster gives a percentage chance of rain, it is not based on strict mathematics, but on past data. The less data available (or factors omitted), the less reliable are the projections. Additionally, there are unknowns that may influence the system, before the time arrives, changing the potential outcome.
Sam,I thought IceSat2 was getting pretty close to that.
Thanks for the statistics tutorial.
Concerning the use of "extent", remote sensing can still not discern the difference between a melt pond and sea water, so even as extent gets progressively more inaccurate, there is not a lot of alternative. At some point in time, detection of the several centimeters difference in height may become possible...
Sam,I thought IceSat2 was getting pretty close to that.
Thanks for the statistics tutorial.
Concerning the use of "extent", remote sensing can still not discern the difference between a melt pond and sea water, so even as extent gets progressively more inaccurate, there is not a lot of alternative. At some point in time, detection of the several centimeters difference in height may become possible...
I still say, no matter what measure one uses, the chances of a BOE this year are vanishingly small.
My hunch is that there is plenty of energy available to melt the ice, but there is a barrier between the ice and the energy beneath.
If that energy can find it's way to the surface......
Quite often systems may behave similarly to random processes, yet not be such at all. In those cases, statistical tests and bounds may be useful, but also be wrong. They can mislead us greatly.
Chaotic systems may for a time exhibit quasi random statistical like behavior within certain bounds. Deviate slightly and the statistics may suddenly not work at all.
Some systems exhibit what appears to be statistical noise and random behavior only to exhibit wildly non-random behavior that far exceeds the statistical bounds. So-called "stiff" equations in chemical engineering behave this way. They appear stable for long periods before some small input accumulates in effects and drives wild changes in the results.
Systems with unrecognized, hidden, or ignored state changes may also exhibit either true or apparent random behavior about a mean, but with changes in the underlying conditions, or slight changes in the mean can walk across a system boundary and suddenly completely change behaviors completely outside any statistical analysis of the previous behavior to that point.
after all there remain the laws of physics and as long as we exclude extraordinary events like impacting asteroidsHow big should an asteroid be?
Can this year reach a BOE? Not totally impossible.
I will be highly surprised if a first BOE does not happen by 2030.
Can this year reach a BOE? Not totally impossible.
I will be highly surprised if a first BOE does not happen by 2030.
And even if we do not reach a true BOE before 2030, there will be little difference between a minimum of 1.8 M km2 vs. < 1.0 M km2 when we consider the impact it will have on climate.
Are people underappreciating the consequences of a BOE?
These are two important positive feedback effects associated with declining ice, no?
Wdmn,
I believe you have it exactly correct.
The IPCC has begun hedging all of its analyses by using probabilities of success, and accepting lower probabilities precisely to avoid the most draconian actions required to avoid calamity. In doing so they forget or neglect several things, including:
1) how much we do not know
2) the time lags in the system
3) how humans react to directly sensed impacts and very poorly to delayed impacts
4) the chaotic nature of the systems
5) the severe consequences of step changes in physical behavior, points of no return, ...
6) how horrible people are at understanding probability and consequences, and reacting to those
7) just how hard it is to take large actions, how slow they are to start, and how slow they are to cause meaningful change
8 ) how resistant people are to sacrifice (no one wants to give up their toys)
9) how dependent society is on growth (even brief periods of stagnation, let alone negative growth, lead to problems, and negative growth of any significance leads to societal collapse)
10) the practical impossibility of achieving and sustaining the negative growth rates required to meet targets of less than 4 degrees C increase in temperature
11) people’s unwillingness to shrink population size, and in fact the in built bias reinforced in all societies and religions to expand population to out populate the “others” thereby winning by head count, and having the bodies needed to do war on the “others” to win in the battles of belief.
11) etc...
Number 10 is particularly troubling. If we consider what flat or negative growth has done to previous societies and civilizations, and use that as a guide to what we can do, it is hard to escape the conclusion that we have already lost the war in its entirety.
It is certainly possible to use renewables to do this. The Netherlands is a case example of success. That is a slow process. And it has serious limits and problems that must be overcome. Many of these problems require societal changes to succeed, e.g. distributed power, high energetic efficiency in design, low waste, working near home, minimal travel, growing our food near where we each live, undoing much of the industrial revolution, ... These are things people are highly resistant to surrendering.
Much of our population has little to no grasp on the importance of the wild world in maintaining the stability of the earths systems. They view population growth as an inherent good, and the wilds as just something to consume. Until we stand shoulder to shoulder unable to move, they cannot see a problem.
And all of these combined take us to an ice free earth in short order, with an ice free arctic being the first and most immediate hallmark.
The denial built into our societal and belief structures, our desire for a better life in the near term, with little or no understanding of the long term consequences, and almost no willingness to fight against the short sighted myopic financial interests that drive us to ruin in the near term, let alone the long term, lead us inexorably to a hothouse earth and to a very early ice free arctic.
Sam
NSIDC Data
A couple of graphs looking at the Arctic Central Seas only, about what melt is required for a BOE of < 1 million km2 extent. The peripheral seas are ignored as they always melt out completely to the extent as makes no difference.
Currently a BOE requires an extent loss from now of circa 7.5 million km2 compared with an average of circa 4.5 million, i.e. circa 65% above average. The most that happened was in 2012, when extent loss from now was circa 20% above average.
So a BOE currently requires a series of circumstances (tipping points?) completely outside and beyond previous experience.
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Area data gives similar results. Note that at minimum area is usually about 65% of extent. So a BOE of 1 million km2 extent might be about 0.65 million km2 area.
Are people underappreciating the consequences of a BOE?
My understanding is that it takes 70-80x as much energy to convert a g of water from me ice to liquid as it does to raise the temp of water 1C. When the ice is melted, we lose a buffer for more rapid heating. We also lose albedo. These are two important positive feedback effects associated with declining ice, no?
I would like to comment on the precautionary principle, because it has been used quite often when discussing climate changes. While this pathway is based on sound reasoning, it may not be the best approach. This principle would actually prevent more action, than it would encourage. While many view this as a positive step (preventing negative outcomes), it can also be viewed negatively (preventing positive outcomes). The precautionary principle would block risky ventures, because they are not proven to be safe...
dnem makes an extremely important point.
The first BOE very likely happens in September. At that point, the power of the Sun over the Arctic is minimal. Let's start there.
...
If the year after the first BOE the Arctic creates the maximum volume on record, then max volume in April will be 19.66 of thin, one year ice. The average Melt from 2006 to 2018 was 17.89, but included thick ice. The maximum let on record was 19.69, more than the Maximum gain.
If everything stayed the same, it is very likely that the year following the first BOE is followed by another
I would like to comment on the precautionary principle, because it has been used quite often when discussing climate changes. While this pathway is based on sound reasoning, it may not be the best approach. This principle would actually prevent more action, than it would encourage. While many view this as a positive step (preventing negative outcomes), it can also be viewed negatively (preventing positive outcomes). The precautionary principle would block risky ventures, because they are not proven to be safe...
A thoughtful post, for which I'd offer a moderately contrasting perspective.
There may be some benefit in presenting a definition and discussion of what the Precautionary Principle entails:
The precautionary principle in environmental science.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1240435/ (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1240435/)
" The precautionary principle, proposed as a new guideline in environmental decision making, has four central components: taking preventive action in the face of uncertainty; shifting the burden of proof to the proponents of an activity; exploring a wide range of alternatives to possibly harmful actions; and increasing public participation in decision making..."
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The difficulty may be less in the Precautionary Principle than how to apply it to societal decision-making. I'd emphasize "taking preventive action in the face of uncertainty." That is, if continuing BAU carries even a small risk of catastrophic consequences, such preventive action is necessary. This wouldn't imply avoiding actions that might be beneficial, rather the opposite.
There's also the matter of what constitutes "action" or "activity." Continuing the status quo must be considered an action. The proposal to, say, burn another gigaton of fossil fuels should be weighed against whether to build a megawatt of solar power. The solar power array shouldn't be viewed as the only "action" or "activity" in this choice.
A BOE leaves the arctic with vast open expanses of bare water going into the arctic night. Open ocean radiates far more heat out into space during the night than ocean covered with ice and snow as an insulator. I really would expect above-record refreezing after a BOE. Enough to preclude a subsequent repeat BOE? I don't know.
A reasonable interpretation. However, we shouldn't ignore a major negative feedback (against all the worrisome positive feedbacks).
A BOE leaves the arctic with vast open expanses of bare water going into the arctic night.
Open ocean radiates far more heat out into space during the night than ocean covered with ice and snow as an insulator.
I really would expect above-record refreezing after a BOE. Enough to preclude a subsequent repeat BOE? I don't know.
Of course, the important date is not first BOE, but when it becomes inevitable. That is almost certainly past.
Of course, the important date is not first BOE, but when it becomes inevitable. That is almost certainly past.
Nothing is inevitable, except death and taxes - Ben Franklin.
Nothing is inevitable, except death and taxes - Ben Franklin.
totally not true, there are point of no returns even for things that have once been avoidable but are not anymore after a certain momentum in relation to the inertia of a given system has been reached.
Nothing is inevitable, except death and taxes - Ben Franklin.
totally not true, there are point of no returns even for things that have once been avoidable but are not anymore after a certain momentum in relation to the inertia of a given system has been reached.
If you are referring to the Arctic, there is no point of no return. Even if we attain a BOE condition, the Arctic will re-freeze (and glaciers expand), if temperatures dictate such. This is simple physics.
Nothing is inevitable, except death and taxes - Ben Franklin.
totally not true, there are point of no returns even for things that have once been avoidable but are not anymore after a certain momentum in relation to the inertia of a given system has been reached.
If you are referring to the Arctic, there is no point of no return. Even if we attain a BOE condition, the Arctic will re-freeze (and glaciers expand), if temperatures dictate such. This is simple physics.
Nothing is inevitable, except death and taxes - Ben Franklin.
totally not true, there are point of no returns even for things that have once been avoidable but are not anymore after a certain momentum in relation to the inertia of a given system has been reached.
I am one of the two that chose 2041-60.
If you are referring to the Arctic, there is no point of no return. Even if we attain a BOE condition, the Arctic will re-freeze (and glaciers expand), if temperatures dictate such. This is simple physics.
I think it"s pretty clear that this thread is about predicting the next BOE. No one is suggesting that the next BOE will be the last one the earth will ever experience.
What's your prediction regarding the next BOE?
This will be a disaster for polar bears. They will not be able to escape in Canada and Greenland, and all will drown near the North pole.
:D
That's not going to happen. But there is no way that Arctic sea ice loss will be good for polar bears.
Why do you think this is unlikely? You wrote last year how the Northern shores of Greenland were cleared of ice at the end of August. It is obvious that there is a high probability that polar bears will fall into the ice trap in the Central Arctic and die.
google how far and how long polar bears can and do swim, even when they don't necessarily have to, you'll be surprised and know why this won't happen the way you describe.
neven's take on this is as spot on as it can get. bad for the bears but they won't drown in numbers.
When a bear swims, its head protrudes only 10 cm.
(https://secure.i.telegraph.co.uk/multimedia/archive/01810/Polarbear_1810939c.jpg)
In a strong storm, it is corny to choke.
Can we please stay on topic?No, everyone needs to have the last word first. ::)
For clarification, the header of the sea ice area chart indicates it's a 5 day moving average.
Since the loss reported for the day is 69k, up from the previous day of 60k, I'm inferring that the latest day total added to the 5 days average is 45k greater loss than the day that dropped out.
69*5 = 345
60*5 = 300
When comparing today's extent loss of 97k to today's area loss of 69k, I'd guess we need to factor in different techniques for measuring as well as a 5 day vs. 1 day measurement period.
(It was his stupebdous work on Alebo Warming Potential that was the trigger).
Nice graphs. However, I question your trend lines. Both the max and min were decreasing fairly constantly for the first decade. However, both max and min have been flat over the past decade.
Nice graphs. However, I question your trend lines. Both the max and min were decreasing fairly constantly for the first decade. However, both max and min have been flat over the past decade.
Is it straight or curved?
Is it straight or curved?
For how i see this, a straight line would be magical.
We are at the beginning of a massive conversion event. Why would the sea ice find a new equilibrium this early in the process? Doesn't sound logical to me.
This question was about shape of trendline not of the extrapolation. Which is better fit straight diagonal line though data or curve I have drawn? (obviously curve but that is of course capable of fitting data better with more parameters/degrees of freedom. Sorry if this wasn't clear.
Oh, sorry, my fault Crandles. I think your trendline is fitting.
I think it is better to show data from beginning than selecting 2000 as starting point.
Note: I don't believe the completely flat trendline at the end, I think it will continue downwards but at a fairly slow rate.
Is it straight or curved? Perhaps not clear enough to be statistically significant, particularly with April.
While residuals are uncorrelated, I think there is still good reason to think shape of trendlines will be somewhat similar between April and Sept: Less volume means more area becomes thin ice and open water so albedo drops and more energy is absorbed ....
If curved then the way this shows seems to be the way it is going.
Nice graphs. However, I question your trend lines. Both the max and min were decreasing fairly constantly for the first decade. However, both max and min have been flat over the past decade.
As the volume goes down losses must go down. There is simply less ice to melt, and certainly less easy peripheral ice to melt.
With the disappearance of multi-year ice, volume loss must go down as well.
As the volume goes down losses must go down. There is simply less ice to melt, and certainly less easy peripheral ice to melt.
With the disappearance of multi-year ice, volume loss must go down as well.
But all this doesn't mean that volume is expected to reach equilibrium. The curve will surely go down, only question is how quickly or slowly.
Nice graphs. However, I question your trend lines. Both the max and min were decreasing fairly constantly for the first decade. However, both max and min have been flat over the past decade.
However, both max and min have been flat over the past decade.
Neither max nor min have been flat for a decade. Min has been slightly flat but above the old average, and climbing for 6 years, likely waiting for volume to catch up before it resumes the march down.
Either acknowledge your "error" or substantiate your claim. That's what good scientist do, right?
However the pattern seems to be that there was increase in volume loss but perhaps it is now going down.
The maximum is -0.14 / yr, and neither is significantly different than zero.
I would say confidently that the recent trends are flat compared to the most recent declines.
QuoteThe maximum is -0.14 / yr, and neither is significantly different than zero.
Your characterization of the maximum is plain wrong. The maximum has kept a steady decline , significantly higher than zero, even when there is much less thick and easy ice to melt.
QuoteThe maximum is -0.14 / yr, and neither is significantly different than zero.
Your characterization of the maximum is plain wrong. The maximum has kept a steady decline , significantly higher than zero, even when there is much less thick and easy ice to melt.QuoteI would say confidently that the recent trends are flat compared to the most recent declines.
You can say it confidently with words, but not with numbers.
Max has been steadily going down even if we pick a very high starting point for the graph, like 2010. See attachment for lines, slopes and R2 of 2010 to present and 2001 to 2010. While it is true that if we pick 2010 the slope improved, it is marching steadily down, even in the absence of easy ice.
Max has been steadily going down even if we pick a very high starting point for the graph, like 2010. See attachment for lines, slopes and R2 of 2010 to present and 2001 to 2010. While it is true that if we pick 2010 the slope improved, it is marching steadily down, even in the absence of easy ice.
I think we all see the same thing here: The loss flatlines and even seems to drop. Which may very well be indicative of a real state change and not a statistical fluke. I think it may very well be the former, but the datapoints are too few to statistically validate any change in trends.
Well, here is a scientist who votes for 2022:
https://www.forbes.com/sites/jeffmcmahon/2018/01/15/carbon-pollution-has-shoved-the-climate-backward-at-least-12-million-years-harvard-scientist-says/#6bd5743b963e
Its worth reminding ourselves that "from the comparison with in situ observations it appears that PIOMAS tends to overestimate thin ice and underestimates thick ice. As the ice thins such systematic errors can affect the overall trend."I think we all see the same thing here: The loss flatlines and even seems to drop. Which may very well be indicative of a real state change and not a statistical fluke. I think it may very well be the former, but the datapoints are too few to statistically validate any change in trends.
I think the loss flatlines (in the case of the Arctic) because total winter extent vs loss is reaching a hard limit - zero - as to how much ice is left over at the end of the melting season.
We have seen a decline in melt season total loss of extent and volume, but that remaining volume is (1) harder to reach and increasingly (2) isn't replaced during the refreeze.
The sun reaches the 80N at the same time, and has the same effect, but there is less ice at lower latitudes.
My instinct now is to watch the winter numbers more closely than summer's, as that's were I think the real harbingers to our first BoE will show up.
Its worth reminding ourselves that "from the comparison with in situ observations it appears that PIOMAS tends to overestimate thin ice and underestimates thick ice. ...
PIOMAS is calibrated to NSIDC sea ice concentration, which has coarse resolution (25x25km). Perhaps NSIDC shows this area with some ice?
I am not trying to discredit PIOMAS, but it's important to understand it's limitations and I'm not there yet.
At the beginning of the month I posted some thickness graphs (PIOMAS volume divided by NSIDC Area) of some individual seas. It showed clearly that in at least some of the smaller seas as summer advanced, the data started to look somewhat dodgy. But that when that starts to happen at least it does tell you that the sea is nearly kaput of ice.I am not trying to discredit PIOMAS, but it's important to understand it's limitations and I'm not there yet.
PIOMAS is known to be:
1. Not very accurate,
and
2. Better than anything else we've got.
Thanks, but I am only seeing one graph.Look again...
I look forward to the other three.
Cheers
Thanks, but I am only seeing one graph.Look again...
I look forward to the other three.
Cheers
Baffin Bay Note the 2000 Average line. That I do NOT understandThe problem is with the PIOMAS data itself. While the volume in the 2000s was modeled as higher than the 2010s, the minimum NSIDC area was almost the same in both decades. In addition, the volume in the 2000s barely reduces for weeks around the minimum, while area continues shrinking. It seems that either PIOMAS did not calibrate itself properly by the NSIDC area data in Baffin Bay as it is supposed to do, or that PIOMAS modeled extremely thick ice in the bay, perhaps due to export from Nares or the CAA, and that ice was the only thing left in September according to the model. I really doubt the second explanation, as PIOMAS lacks the resolution to achieve that kind of result.
the volume in the 2000s barely reduces for weeks around the minimum, while area continues shrinking.Just as CAB ice continues to thicken long after 'fringe' sea ice melts out (causing volume max to follow [and not follow closely] area/extent max), CAB ice will start thickening before the remaining pack stops melting at the edges. The North Pole summer is shorter than the 80ºN summer - it starts later and ends sooner.
Thought I would have another look at thickness at minimum and maximum.
Graphs of volume, area & thickness at min and max attached.
Just says to me two things
- it will be volume loss wot does it,
- back in the early years average thickness at maximum was less than at minimum by about 1 metre. That's a lot. This gradually declined until reversed in 2010, i.e. average thickness at maximum more than at minimum (by about 0.1 to 0.2 metres). Pourquoi ? All to do with the amount and location of area and volume loss, methinks, but it made me blink.
Still say BOE sometime in the 2020's, but imagine (using the 1 million km2 rule)..
Paris Agreement Does Not Rule Out Ice-Free Arctic
https://phys.org/news/2019-07-paris-agreement-ice-free-arctic.html
Research published in this week's issue of Nature Communications reveals a considerable chance for an ice-free Arctic Ocean at global warming limits stipulated in the Paris Agreement. Scientists from South Korea, Australia and the U.S. used results from climate models and a new statistical approach to calculate the likelihood for Arctic sea ice to disappear at different warming levels.
Using 31 different climate models, which exhibit considerable inter-dependence, the authors find that there is at least a 6% probability that summer sea ice in the Arctic Ocean will disappear at 1.5 °C warming above preindustrial levels—a lower limit recommended by the Paris Agreement of the United Nations Framework Convention on Climate Change. For a 2°C warming, the probability for losing the ice rises to at least 28%. Most likely we will see a sea ice-free summer Arctic Ocean for the first time at 2 to 2.5°C warming.
Open Access: R. Olson, S.-I. An, Y. Fan, W. Chang, J. P. Evans. A novel method to test non-exclusive hypotheses applied to Arctic ice projections from dependent models (https://www.nature.com/articles/s41467-019-10561-x). Nature Communications, 2019
I don't think many regulars on this forum think there is much chance for a BOE to wait until global temps have risen over 2C. Personally, I expect it to happen before we reach 1.5C.
I can get that up to 84.5% for 2017:
https://forum.arctic-sea-ice.net/index.php/topic,2031.0.html
When will be break PIOMAS 2012 September record?
2017 (In General) 60 (51.7%)
2018-2019 7 (6%)
2020-2023 5 (4.3%)
2022-2025 2 (1.7%)
2024-2027 70 (0%)
2026-2029 0 (0%)
2028-2030 0 (0%)
After 2030 1 (0.9%)
Never 3 (2.6%)
2017 by month: July 1 (0.9%)
2017 by month: August 16 (13.8%)
2017 by month: September 21 (18.1%)
So just 15.5% thought it wouldn't be 2017, but to be fair the volume was at a clear record low for the time of year and had been for some time when the poll closed 30 May 2017.
Agree there is some self selection bias: alarmists more likely to be active on this forum, therefore no surprise if the poll results tend towards alarmism. OTOH with 2017 data available at the time, perhaps it is not too surprising if high proportion of people were predicting new minimums to occur.
>Last year was rather subdued
Perhaps people are learning from their errors? Maybe I posted my infamous 4 parameter gompertz fit graphs frequently enough. ;)
many of the regulars are realists . Also .. as a wake-up call a BOE would be better sooner than later .
many of the regulars are realists . Also .. as a wake-up call a BOE would be better sooner than later .
Sorry bro, no such luck. Noone will give a s**t about BOE even when it happens especially that by definition (the 1 M sq km threshold) it will still include some remnants of the arctic ice. There's going to be no wake up call, no more than 2007 or 2012. Extreme, previously unimaginable (and unforeseen by models) things happened in 07 and 12 and yet no one gave a s**t either.
A BOE could happen even this year but it might not come until the 30s. BOE is not the wake up call. Global crop-failures or millions (in developed countries) losing their homes would be. I hope (and think) that these will not happen in my lifetime. If they do, then MAYBE, just maybe, humanity will try to change
many of the regulars are realists . Also .. as a wake-up call a BOE would be better sooner than later .
Sorry bro, no such luck. Noone will give a s**t about BOE even when it happens especially that by definition (the 1 M sq km threshold) it will still include some remnants of the arctic ice. There's going to be no wake up call, no more than 2007 or 2012. Extreme, previously unimaginable (and unforeseen by models) things happened in 07 and 12 and yet no one gave a s**t either.
A BOE could happen even this year but it might not come until the 30s. BOE is not the wake up call. Global crop-failures or millions (in developed countries) losing their homes would be. I hope (and think) that these will not happen in my lifetime. If they do, then MAYBE, just maybe, humanity will try to change
sorry but i disagree here, i dunno where you live but in europe the movements for sustainability is getting stronger by the month and i'm totally convinced that an extreme event would again increase the percentage of awareness and once the critical mass is reached we could even end in an environmental dictatorship. i mean kind of widely spread prohibition that will not solve the problem because it's too late but destroy what still working.
i do not expect any followership on such thoughts. only thing i say is that: study how communism evolved and played out and who knows whether it could repeat in the green spectrum after the red spectrum didn't succeed. too complicated and OT to take it further here.
A Disney film about a polar bear cub that lost its mother while the ice was melting and was adopted by a beluga whale will have more impact than a BOE.
Unless there are serious immediate consequences in the lives of several millions of people, the BOE will be just an extra degree in the boiling pan with frog at the bottom.
The BOE is a psychological milestone mostly for people that follow the arctic. Even for people that are concerned with climate change, it's just another piece of terrible news, that are becoming more and more common.
After a BOE there won't be debates about climate change, it will be quite clear. What happens in the Arctic does not stay in the Arctic.
After a BOE, anthropogenic climate change won't even matter anymore. Human emissions will drop significantly the year after the first BOE. Plastic pollution will pretty much stop a few years after. About the only impact humans will have on the planet at that point will be that of war, and it won't be for long, we'll be fighting with stones and sticks after a while.
After a BOE there won't be debates about climate change, it will be quite clear. What happens in the Arctic does not stay in the Arctic.
After a BOE, anthropogenic climate change won't even matter anymore. Human emissions will drop significantly the year after the first BOE. Plastic pollution will pretty much stop a few years after. About the only impact humans will have on the planet at that point will be that of war, and it won't be for long, we'll be fighting with stones and sticks after a while.
This is hyperbole. If extent slips below 1,000,000 km2 for a day and then heads into a relatively normal (for these abnormal times) freeze season, it will not result in chaos and collapse. It will be a just another ratchet step down that road. When we have a few summers in a row with no ice, then you might be right.
Find me a paper that describes what happens after the first BOE...That seems to be very uncertain. The IPCC states "with high confidence" that there will be no hysteresis (but that is because they excluded feedback from all of their models) and that the Arctic will just refreeze like normal. I doubt that, because there should be more mixing caused by stronger wave action due to the longer wind fetch.
The IPCC states "with high confidence" that there will be no hysteresis (because they excluded feedback from all of their models) and that the Arctic will just refreeze like normal.
As to linkages and the effects on temperate weather patterns, effects are uncertain. Some results indicate that weather will remain variable. Jennifer Francis etc do not agree.
What seems obvious is that there will be a lot more evaporation from the open ocean in the autumn. But the relative increase of humidity and latent heat in the atmosphere won't be large, not in Western Europe.
The abrupt changes in planetary climate that a BOE will bring are not magic. They are simple physics. The Earth has had a planetary refrigerator for likely millions of years.
QuoteThe IPCC states "with high confidence" that there will be no hysteresis (because they excluded feedback from all of their models) and that the Arctic will just refreeze like normal.
I'm convinced that after the first BOE the Arctic will refreeze like normal, if by normal you mean later than ever and by the end of the freezing season there is a record low amount of first year ice. No instant hysteresis. Hysteresis happens in the years after the BOE as consecutive BOE's happen at earlier dates.
With 1.5°C of global warming, one sea ice-free Arctic summer is projected per century.
This likelihood is increased to at least one per decade with 2°C global warming.
Effects of a temperature overshoot are reversible for Arctic sea ice cover on decadal time scales (high confidence).
And in all those threads I’ve made clear the existence of massive ice sheets that offset the warming. Ice sheets that do not exist today except for Greenland. I also made clear that the time frame of these events of the past happen over centuries and millennia, not decades.
It’s all right there in the same literature you now allude to. You just don’t want to see it.
Yes, it would refreeze later than usual, and the ice would be thinner next year with very little multi-year ice. Which would give a much higher probability of another BOE. Probably earlier in the melting season.
Yes, you made clear that YOU THINK that BOE will bring disaster and pretty much and end of all life.
You never supported your claims with any literature and disregarded any literature I cited (many times!) even from pretty reliable journals,
These show that the changes in the past happened in decades not centuries or millenia and the changes were huge and widespread (Greenland temp change at the end of the last ice age of 8-15 C in a mere decades or years!).
What happened to the hippie generation?
The abrupt changes in planetary climate that a BOE will bring are not magic. They are simple physics. The Earth has had a planetary refrigerator for likely millions of years. After a BOE that refrigerator fails and the NH will know true climate change. There won't be any denying because we'll be busy surviving.
I'm not arguing against logic here. It is frustrating to see how intelligent people who are aware of the role of arctic sea ice on atmospheric and oceanic patterns can't see the destruction that will ensue as the arctic disappears. The destruction has already started and the Arctic has barely begun to change.
But I may be wrong, so let's get to the science. Find me a paper that describes what happens after the first BOE, that doesn't ignore the ASI teleconections to the rest of the world and predicts a BOE much sooner than 2070.
Good luck with it.
The impacts of a BOE is simply a continuum of what we are already seeing
The abrupt changes in planetary climate that a BOE will bring are not magic. They are simple physics. The Earth has had a planetary refrigerator for likely millions of years. After a BOE that refrigerator fails and the NH will know true climate change. There won't be any denying because we'll be busy surviving.
I'm not arguing against logic here. It is frustrating to see how intelligent people who are aware of the role of arctic sea ice on atmospheric and oceanic patterns can't see the destruction that will ensue as the arctic disappears. The destruction has already started and the Arctic has barely begun to change.
But I may be wrong, so let's get to the science. Find me a paper that describes what happens after the first BOE, that doesn't ignore the ASI teleconections to the rest of the world and predicts a BOE much sooner than 2070.
Good luck with it.
The impacts of a BOE is simply a continuum of what we are already seeing. The very low SIE and SIA we are reaching now are already impacting the weather across the NH. While we define a BOE as less than 1 million square kilometers, NH weather will see no real diffirence between 1.4 and 0.8 million square kilometers.
Mankind (and nature) is more resilient than many people think.
Look at what is happening in Central America, Mexico and the US / Mexico border.The abrupt changes in planetary climate that a BOE will bring are not magic. They are simple physics. The Earth has had a planetary refrigerator for likely millions of years. After a BOE that refrigerator fails and the NH will know true climate change. There won't be any denying because we'll be busy surviving.
I'm not arguing against logic here. It is frustrating to see how intelligent people who are aware of the role of arctic sea ice on atmospheric and oceanic patterns can't see the destruction that will ensue as the arctic disappears. The destruction has already started and the Arctic has barely begun to change.
But I may be wrong, so let's get to the science. Find me a paper that describes what happens after the first BOE, that doesn't ignore the ASI teleconections to the rest of the world and predicts a BOE much sooner than 2070.
Good luck with it.
The impacts of a BOE is simply a continuum of what we are already seeing. The very low SIE and SIA we are reaching now are already impacting the weather across the NH. While we define a BOE as less than 1 million square kilometers, NH weather will see no real diffirence between 1.4 and 0.8 million square kilometers.
Agreed. It will impact the weather, but as far as a collapse of civilization as we know it, hardly. Mankind (and nature) is more resilient than many people think.
Mankind (and nature) is more resilient than many people think.
Yes, you and magnamentis may be right but I think that it is just wishful thinking on your part. What happened to the hippie generation? The same thing will happen to these young green voters...unfortunately for all of us. But we will most likely see which of us is right soon enough
I know it is OT (sry) but I attach this chart for gerontocrat regarding drowning in the Mediterranean and the number of migrants.The OT continues.
Truth is migrants arrive mostly (exception: Syrian war refugees) looking for a job and once they are not welcome anymore, they get the message and don't come anymore
To add to the discussion about the begining of the end, June 2019 was the warmest month of June regarding SST in Bering sea and Bering strait according to reanalysis.
Aans as an illustration, Kotzebue is near or above record Tn and Td since 4 days : http://ogimet.com/cgi-bin/gsynres?ind=70133&ano=2019&mes=7&day=11&hora=12&min=0&ndays=30
The transport is strong this year trough the strait, and so the SST are more asymetric than usual, but despite this all the Bering sea and Chuckchi sea are at or above record level, and strong currents are burring this heat to great depth. The chart from the DMI is now saturated with red, after reaching a "low" the 4th. An incredible amount of heat is building into Arctic Ocean, and is now wanting to ease.
BOE-year: "aaaah, blue ocean" "oh, nothing happens, it just refreezes"
BOE-year+1: "oh, again blue ocean" and we will have some weird weather, but those are just 'incidents'
BOE-year+2: "that's weird, 3rd BOE in a row and too early" and weather patterns become unpredictable in northern hemisphere with lots of extreme weather and reality finally sinks in
In recent interview Peter Wadhams threw out a concept I hadn't heard before. With continued loss of ASI there could be a tipping point where polar jet stream doesn't just weaken and wobble, but just goes away completely.I suppose that would be the single large Hadley cell extending from equator to pole? As in hothouse paleoclimates.
I think we're already seeing hysteresis with changes in feedback and increased uptake of heat, not to mention the extermination of ice more than 4 years old. It would take generations of pre-1980's weather to restore the pack to the state it was in before 2010, much less earlier.Find me a paper that describes what happens after the first BOE...That seems to be very uncertain. The IPCC states "with high confidence" that there will be no hysteresis ...
<snippage>
The research like Tietsche et al and Schroeder and Connolley
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007GL030253
suggests that the lack of ice from BOE means little snow can be supported by ice during time when there are reasonable amounts of snow. The ice gets thicker than usual (not thinner) during the freeze season due to lack of insulating snow.
After two years it gets back to pretty near normal. This research is covering situation where unusual weather causes a BOE when the climate is not really ready for a BOE yet.
I think arguing that one BOE causes next year to have longer BOE is like arguing that a record low ice volume means the next year will definitely beat that record.
The impacts of a BOE is simply a continuum of what we are already seeing. The very low SIE and SIA we are reaching now are already impacting the weather across the NH. While we define a BOE as less than 1 million square kilometers, NH weather will see no real diffirence between 1.4 and 0.8 million square kilometers.
A BOE will most certainly not cause the end of all life on earth, not by a long shot. Only the end of modern civilization and, overtime, a huge chunk of the human population. Most of nature will be just fine after a few hundred years of climate stability. A scientist 50k years from now will
Archimid, your prediction cut off in mid-sentence. What was it?
<snippage>Hi Glen, I'd like to read/listen to this interview. Do you perhaps have a link?
In recent interview Peter Wadhams threw out a concept I hadn't heard before. With continued loss of ASI there could be a tipping point where polar jet stream doesn't just weaken and wobble, but just goes away completely. I don't know if that is at all realistic, but if it did happen it would seem to be like Jennifer Francis thesis on steroids, with potential drastic changes in weather patterns, or just weather chaos until new patterns emerged. I guess there's always a pattern, but if there was a complete loss of polar jet stream steering of weather systems that just seems like crazy town.
I asked for a resource with a BOE before 2070 for a good reason. If the model that you use says the arctic will have ice in the summer 50 years from now, that model is missing something huge, a BOE will happen much sooner than that. Thus a model that has the ice going by 2070 is very likely to assume the ice will return, because it is already underestimating the changes happening in the Arctic.
The paper you posted uses HadCM3. From a quick search HadCM3 predicts ice free during summer somewhere around 2080. That ain't happening. Please try a newer source, with a model that makes a prediction for the first BOE that more closely matches the observations.
Quotesuggests that the lack of ice from BOE means little snow can be supported by ice during time when there are reasonable amounts of snow. The ice gets thicker than usual (not thinner) during the freeze season due to lack of insulating snow.
I don't understand. Can you explain to me how can there be conditions for sea ice formation but no condition for snow? It seems the opposite will happen. There will be more snow than ever before. By your own argument that should result in warming. The data clearly indicates that snow fall during fall is increasing.
QuoteAfter two years it gets back to pretty near normal. This research is covering situation where unusual weather causes a BOE when the climate is not really ready for a BOE yet.
Actually, this research is covering an imaginary situation where the first BOE happens close to 2080.
QuoteI think arguing that one BOE causes next year to have longer BOE is like arguing that a record low ice volume means the next year will definitely beat that record.
All things being equal, a record low volume increases the chances of a lower volume next year for the mere fact of having a lower starting point. But the argument of why the first BOE highly increases the chances of a BOE the year after is much more nuanced than that and with better fundamentals.
But they are better than nothing, you have to work with the tools you have got not the ones you would like, and the models show the same thing for 2020 2040 and 2060.
You might want a newer source and better model, but basically tough: If it doesn't exist, then you are not going to get it. If there are two papers saying the same thing, then another paper is unlikely to be published unless it is saying something markedly different.
You don't think missing the first BOE by 4 decades (possibly more) is something markedly different?
The abrupt changes in planetary climate that a BOE will bring are not magic. They are simple physics. The Earth has had a planetary refrigerator for likely millions of years. After a BOE that refrigerator fails and the NH will know true climate change. There won't be any denying because we'll be busy surviving.
I'm not arguing against logic here. It is frustrating to see how intelligent people who are aware of the role of arctic sea ice on atmospheric and oceanic patterns can't see the destruction that will ensue as the arctic disappears. The destruction has already started and the Arctic has barely begun to change.
But I may be wrong, so let's get to the science. Find me a paper that describes what happens after the first BOE, that doesn't ignore the ASI teleconections to the rest of the world and predicts a BOE much sooner than 2070.
Good luck with it.
The impacts of a BOE is simply a continuum of what we are already seeing. The very low SIE and SIA we are reaching now are already impacting the weather across the NH. While we define a BOE as less than 1 million square kilometers, NH weather will see no real diffirence between 1.4 and 0.8 million square kilometers.
I found this analysis of a BOE event to be rather informative.
https://climatetippingpoints.info/2019/04/02/fact-check-will-an-ice-free-arctic-trigger-a-climate-catastrophe/
11 3.3.8 Sea ice
12
13 Summer sea ice in the Arctic has been retreating rapidly in recent decades. During the period 1997 to 2014
14 for example, the monthly mean sea-ice extent during September decreased on average by 130,000 km² per
15 year (Serreze and Stroeve, 2015). This is about four times as fast as the September sea-ice loss during the
16 period 1979 to 1996. Also sea-ice thickness has decreased substantially, with an estimated decrease in ice
17 thickness of more than 50% in the central Arctic (Lindsay and Schweiger, 2015). Sea-ice coverage and
18 thickness also decrease in CMIP5-model simulations of the recent past, and are projected to decrease in the
19 future (Collins et al., 2013). However, the modeled sea-ice loss in most CMIP5 models is much weaker
20 than observed. Compared to observations, the simulations are weak in terms of their sensitivity to both
21 global mean temperature rise (Rosenblum and Eisenman, 2017) and to anthropogenic CO2 emissions (Notz
22 and Stroeve, 2016). This mismatch between the observed and modeled sensitivity of Arctic sea ice implies
23 that the multi-model-mean response of future sea-ice evolution probably underestimates the sea-ice loss for
24 a given amount of global warming. To address this issue, studies estimating the future evolution of Arctic
25 sea ice tend to bias correct the model simulations based on the observed evolution of Arctic sea ice in
26 response to global warming. Often based on such bias correction, pre-AR5 and post-AR5 studies agree that
27 for 1.5 °C global warming relative to pre-industrial levels, the Arctic Ocean will maintain a sea-ice cover
28 throughout summer for most years (Collins et al., 2013; Notz and Stroeve, 2016; Screen and Williamson,
29 2017; Jahn, 2018; Niederdrenk and Notz, 2018; Sigmond et al., 2018). For 2°C global warming relative to
30 pre-industrial levels, chances of an ice-free Arctic during summer are substantially higher (Screen and
31 Williamson, 2017; Jahn, 2018; Niederdrenk and Notz, 2018; Screen et al., 2018; Sigmond et al., 2018). The
32 Arctic is very likely to have experienced at least one ice-free Arctic summer after about 10 years of
33 stabilized warming at 2°C compared to after about 100 years of stabilized warming at 1.5°C (Jahn, 2018;
34 Screen et al., 2018; Sigmond et al., 2018). For a specific given year under stabilized warming of 2°C,
35 studies based on large ensembles of simulations with a single model estimate the likelihood for ice-free
36 conditions as 35% without a bias correction of the underlying model (Sanderson et al., 2017; Jahn, 2018);
37 as between 10% and >99% depending on the observational record used to correct the sensitivity of sea ice
38 decline to global warming in the underlying model (Niederdrenk and Notz, 2018); and as 19% based on a
39 procedure to correct for biases in the climatological sea ice coverage in the underlying model (Sigmond et
40 al., 2018). The uncertainty of the first year of the occurrence of an ice-free Arctic Ocean arising from
41 internal variability is estimated to be about 20 years (Notz, 2015; Jahn et al., 2016).
42
43 The more recent estimates of the warming necessary to achieve an ice-free Arctic Ocean during summer are
44 lower than the ones given in AR5 (about 2.6C-3.1C relative to preindustrial or 1.6C-2.1C global
45 warming relative to the present day), which was similar to the estimate of 3C relative to preindustrial
46 levels (or 2C global warming relative to the present day) by Mahlstein and Knutti (2012) based on bias47 corrected CMIP3 models. Rosenblum and Eisenman (2016) explain why the sensitivity estimated by
1 Mahlstein and Knutti (2012) might be too low, estimating instead that September sea ice in the Arctic
2 disappears for 2°C relative to preindustrial (or about 1°C global warming relative to the present day), in line
3 with the other recent estimates. Notz and Stroeve (2016) use the observed correlation between September
4 sea-ice extent and cumulative CO2 emissions to estimate that the Arctic Ocean would become nearly sea5 ice-free during September with a further 1000 Gt of emissions, which also implies a sea-ice loss at about
6 2°C global warming. Some of the uncertainty in these numbers derives from the possible impact of aerosols
7 (Gagne et al., 2017) and of volcanic forcing (Rosenblum and Eisenman, 2016). During winter, little Arctic
8 sea ice is projected to be lost for either 1.5°C or 2ºC global warming (Niederdrenk and Notz, 2018).
9
10 Regarding the behavior of Arctic sea ice under decreasing temperatures following a possible overshoot of a
11 long-term temperature target, a substantial number of pre-AR5 studies have found that there is no indication
12 of hysteresis behavior of Arctic sea ice (Holland et al., 2006; Schroeder and Connolley, 2007; Armour et
13 al., 2011; Sedláček et al., 2011; Tietsche et al., 2011; Boucher et al., 2012; Ridley et al., 2012). In
14 particular, the relationship between Arctic sea-ice coverage and GMST is found to be indistinguishable
15 between a warming scenario and a cooling scenario. These results have been confirmed by post-AR5
16 studies (Li et al., 2013; Jahn, 2018), which implies high confidence that an intermediate temperature
17 overshoot has no long-term consequences for Arctic sea-ice coverage.
33 Loss of sea ice
34 Sea ice has been a persistent feature of the planet’s polar regions (Polyak et al., 2010) and is central to
35 marine ecosystems, people (e.g. food, culture and livelihoods) and industries (e.g. fishing, tourism, oil and
36 gas, and shipping). Summer sea ice in these regions (e.g. Arctic, Antarctic and Southern Ocean), however,
37 has been retreating rapidly in recent decades (Section 3.3.8) with an assessment of the literature revealing
38 that a fundamental transformation is occurring in polar organisms and ecosystems driven by climate change
39 (high agreement, robust evidence) (Larsen et al., 2014). These changes are strongly affecting people in the
40 Arctic who have close relationships with sea ice and associated ecosystems, and are facing major adaptation
41 challenges as a result of sea level rise, coastal erosion, the accelerated thawing of permafrost, changing
42 ecosystems and resources, and many other issues (Ford, 2012; Ford et al., 2015).
43
44 There is considerable and compelling evidence that a further increase of 0.5°C from today in average global
45 surface temperature will lead to multiple levels of impact on a variety of organisms - from phytoplankton to
46 marine mammals some of the most dramatic changes occurring in the Arctic Ocean and Western Antarctic
47 Peninsula (Turner et al., 2014, 2017b; Steinberg et al., 2015; Piñones and Fedorov, 2016).
1
2 The impacts of climate change on sea ice is part of the focus of the IPCC Special Report on the Ocean and
3 Cryosphere in a Changing Climate (SROCC), due to be released in 2019. Therefore, without intending to be
4 comprehensive, there are a range of responses to the loss of sea ice that are occurring and are likely to
5 increase at 1.5°C and 2°C of global warming. Photosynthetic communities such macroalgae, phytoplankton,
6 and microalgae dwelling on the underside of floating sea ice are changing due to increased temperatures,
7 light, and nutrient levels. As sea ice retreats, mixing of the water column increases, and phototrophs have
8 increased access to seasonally high levels of solar radiation (Dalpadado et al., 2014; W.N. Meier et al., 2014)
9 (medium agreement, medium evidence). These changes are very likely to stimulate fisheries productivity in
10 high latitude regions by mid-century (Cheung et al., 2009, 2010, 2016b; Lam et al., 2014), with evidence of
11 this is already happening for several fisheries species in high latitude regions in the northern hemisphere
12 such as the Bering Sea, although these ‘positive’ impacts may be relatively short-lived (Hollowed and
13 Sundby, 2014; Sundby et al., 2016). In addition to the impact of climate change on fisheries via impacts on
14 NPP, there are also direct effects of temperature on fish, which may have a range of impacts (Pörtner et al.,
15 2014). Sea ice in Antarctica is undergoing changes that exceed those seen in the Arctic (Maksym et al.,
16 2011; Reid et al., 2015) with increases in sea ice coverage in the western Ross Sea being accompanied by
17 strong decreases in the Bellingshausen and Amundsen seas (Hobbs et al., 2016). While Antarctica is not
18 permanently populated, the ramifications of changes to the productivity of vaste regions such as the Southern
19 Ocean has substantial implications as far as ocean foodwebs and fisheries are concerned.
Global warming of 1.5C IPCC draft report, sorry if this has been quoted and discussed before. Probably not supposed to quote it yet but at this level and if it is available....In other words, it seems likely that IPCC will accept that a temperature overshoot will occur, but no matter, "We have the technology, we can rebuild the climate". A bit of BECCS here, a bit of Direct Carbon Capture there, and everything will be fixed.QuoteIn particular, the relationship between Arctic sea-ice coverage and GMST is found to be indistinguishable between a warming scenario and a cooling scenario. These results have been confirmed by post-AR5 studies (Li et al., 2013; Jahn, 2018), which implies high confidence that an intermediate temperature overshoot has no long-term consequences for Arctic sea-ice coverage.
Global warming of 1.5C IPCC draft report, sorry if this has been quoted and discussed before. Probably not supposed to quote it yet but at this level and if it is available....And we are not at global 1.5 °C global warming now. Is it truthful to say that the Arctic Ocean is "maintaining a sea ice cover"?QuoteOften based on such bias correction, pre-AR5 and post-AR5 studies agree that for 1.5 °C global warming relative to pre-industrial levels, the Arctic Ocean will maintain a sea-ice cover throughout summer for most years.
And we are not at global 1.5 °C global warming now. Is it truthful to say that the Arctic Ocean is "maintaining a sea ice cover"?
Hmm. I am thinking you have a point and the language needs to be tightened up: Does Arctic Ocean include the surrounding seas?
Also is "will maintain a sea-ice cover throughout summer for most years" being used as just the opposite of "an ice-free Arctic during summer" and hence former includes partial coverage during summer or is partial coverage a separate category that isn't discussed and hence excluded from 'maintaining cover throughout summer for most years' category?
If a 3 category interpretation, then what is written seems wrong, or if seas are excluded, highly likely to be wrong before 1.5C is reached.
<snippage>Hi Glen, I'd like to read/listen to this interview. Do you perhaps have a link?
In recent interview Peter Wadhams threw out a concept I hadn't heard before. With continued loss of ASI there could be a tipping point where polar jet stream doesn't just weaken and wobble, but just goes away completely. I don't know if that is at all realistic, but if it did happen it would seem to be like Jennifer Francis thesis on steroids, with potential drastic changes in weather patterns, or just weather chaos until new patterns emerged. I guess there's always a pattern, but if there was a complete loss of polar jet stream steering of weather systems that just seems like crazy town.
Hmm. I am thinking you have a point and the language needs to be tightened up: Does Arctic Ocean include the surrounding seas?
Also is "will maintain a sea-ice cover throughout summer for most years" being used as just the opposite of "an ice-free Arctic during summer" and hence former includes partial coverage during summer or is partial coverage a separate category that isn't discussed and hence excluded from 'maintaining cover throughout summer for most years' category?
If a 3 category interpretation, then what is written seems wrong, or if seas are excluded, highly likely to be wrong before 1.5C is reached.
Just like caveats about the limitations of various measurement methods, we need to remind ourselves of the fact that IPPC documents are essentially political statements.
After the scientists have had their say, the politicians, bureaucrats and diplomats take over and nothing gets put into the final report unless there is consensus.
When you couple this with the fact that most reports are at least five years old, they are out of touch with reality, and I would say for some, intentionally so.
The result is an anodyne word salad that should be taken with a large grain of salt.
It will be, however, a good document for whatever generations come after us, about how we said a great deal and accomplished little.
However, the modeled sea-ice loss in most CMIP5 models is much weaker than observed. Compared to observations, the simulations are weak in terms of their sensitivity to both global mean temperature rise (Rosenblum and Eisenman, 2017) and to anthropogenic CO2 emissions (Notz and Stroeve, 2016).
This mismatch between the observed and modeled sensitivity of Arctic sea ice implies that the multi-model-mean response of future sea-ice evolution probably underestimates the sea-ice loss for a given amount of global warming.
To address this issue, studies estimating the future evolution of Arctic Sea Ice tend to bias correct the model simulations based on the observed evolution of Arctic sea ice in response to global warming.
Often based on such bias correction, pre-AR5 and post-AR5 studies agree that for 1.5 °C global warming relative to pre-industrial levels, the Arctic Ocean will maintain a sea-ice cover throughout summer for most years
In particular, the relationship between Arctic sea-ice coverage and GMST is found to be indistinguishable between a warming scenario and a cooling scenario. These results have been confirmed by post-AR5 studies (Li et al., 2013; Jahn, 2018), which implies high confidence that an intermediate temperature overshoot has no long-term consequences for Arctic sea-ice coverage.
For warming above 2 °C, frequent ice-free conditions can be expected, potentially for several months per year. Although sea-ice loss is generally reversible for decreasing temperatures, sea ice will only recover to current conditions if atmospheric CO2 is reduced below present-day concentrations.
These changes are very likely to stimulate fisheries productivity in high latitude regions by mid-century
On the consequences of a BOE according to Crandles post:"I totally believe that fish population may increase in the arctic because of warmer water and better light."QuoteThese changes are very likely to stimulate fisheries productivity in high latitude regions by mid-century
Absolute madness. I totally believe that fish population may increase in the arctic because of warmer water and better light. However that is almost an irrelevant fact, relative with the myriad of changes that are happening as the Arctic melts.
This mentions nothing about changes in atmospheric currents that are already beginning, nor oceanic currents, nor acceleration of Greenland melt, nor forest fires, nor methane release...
Really, this part of the document is a work of fiction. It mentions possible positive feedbacks but it ignores possible negative impacts. This document misleads the proper risk assessment of the Arctic.
Krill are a key part of the delicate Antarctic food chain. They feed on marine algae and are a key source of food for whales, penguins and seals. ... ...the ice that is home to the algae and plankton on which krill feed is retreating
The water beneath a snow-covered expanse of ice 1 metre thick hardly seems like a good home for light-loving creatures. But microscopic phytoplankton, which rely on the sun for their nutrients and form the base of Arctic food webs, have managed to thrive under ice sheets that are thinning as the poles become warmer.
The buried “bloom” of phytoplankton – the largest ever found underneath an ice shelf – was four times more concentrated than blooms found in the open ocean. Some say its discovery could mark the first major change in the Arctic ecosystem as a result of climate change.
“We had no clue [they existed],” says Kevin Arrigo of Stanford University in Stanford, California, although he says researchers had found hints of blooms under the ice in the past.
Remote sensing technology, which monitors ocean life from space, cannot detect blooms through the ice. Arrigo and other researchers came across the bloom by accident on a cruise in Alaska’s Chukchi Sea. Their icebreaker was cutting through ice that was only 1 metre thick – compared to the 3-metre thickness in the past – and was pockmarked with pools of melted ice, which allow light through.
What is most amazing, Arrigo says, is that the column of phytoplankton extended downwards for 70 metres and was extremely dense. “It was like pea soup,” he says, “and not a lot of light gets through pea soup.”
Although rarely seen, under-ice blooms such as this one are almost certainly widespread. Arrigo says that most of the Arctic has the right conditions of shallow waters and nutrients. But finding out just how prevalent they are and when they bloom may prove difficult. “A ship is a needle in the haystack,” says Jean-Éric Tremblay of Université Laval in Quebec, Canada. He suggests that researchers might need to use multiple methods, such as sampling buoys, to detect them in the future.
It’s important we try, though. Although no one knows for sure how often blooms occurred under ice sheets in the past, they will probably bloom earlier in the year as the ice sheet thins and completes its summer cycle earlier and earlier, Arrigo says.
This could throw off the timing of the entire Arctic food web. When the ice sheet melts in the spring, zooplankton move into areas of open water to feed on phytoplankton, and in turn become food for fish. If they follow the seasons rather than the phytoplankton blooms, they may arrive too late.
Larger animals that feed directly on phytoplankton might be even more affected. “A whale in Baja California has no way of knowing the bloom will happen a month earlier this year and can’t get there any faster,” says Arrigo.
“These blooms could perhaps be one of the first major responses we can see with climate change,” says C.J. Mundy of the University of Manitoba in Winnipeg, Canada.
The first mistake is to associate Arctic Sea Ice with global temperatures. If Antarctica cooled 10C and the Arctic warmed 10C the Arctic would melt with zero degrees of global warming.
Bias correct... I honestly don't know exactly what that means, but that never stopped me from speculating before, so here we go.
I assume bias correction involves tinkering with parameters and functions until the model produces a better match for the observations. Then the future results are expected to produce better result. If that's the case, I understand the scientific validity and necessity of bias correction. It is a process of perpetual improvement.
Bias correcting a model that has the wrong shape (strait line vs exponential) will still produce the wrong result. How do we know if the model has the wrong shape? We don't, unless a model with a different shape shows better skill.
This paper says that the ice will be gone 2 months during summer, so from mid July to mid September, but there will be no hysteresis. That is quite simply unbelievable and it doesn't even pass a sanity check.
Even more unbelievable is "sea ice will only recover to current conditions if atmospheric CO2 is reduced below present-day concentrations."
The sea ice disappearance might have started because of CO2, but the acceleration of sea ice loss is not because of CO2, as the failure of the models prove. The loss of sea ice is now mostly do to albedo feedback, jetstream destabilization and local Arctic GHG, not CO2. Reducing CO2 back to historic levels will eventually restore the ice, but that will take decades or centuries.
it ignores possible negative impacts.
a fundamental transformation is occurring in polar organisms and ecosystems driven by climate change (high agreement, robust evidence) (Larsen et al., 2014). These changes are strongly affecting people in the Arctic who have close relationships with sea ice and associated ecosystems, and are facing major adaptation challenges as a result of sea level rise, coastal erosion, the accelerated thawing of permafrost, changing ecosystems and resources, and many other issues (Ford, 2012; Ford et al., 2015).
There is considerable and compelling evidence that a further increase ....
1. Yes, certainly true if there is a redistribution of temperatures, but is this likely?
Warming in the Arctic has been much faster than the rest of the world in both observations and model simulations, a phenomenon known as the Arctic amplification (AA) whose cause is still under debate. By analyzing data and model simulations, here we show that large AA occurs only from October to April and only over areas with significant sea-ice loss. AA largely disappears when Arctic sea ice is fixed or melts away. Periods with larger AA are associated with larger sea-ice loss, and models with bigger sea-ice loss produce larger AA. Increased outgoing longwave radiation and heat fluxes from the newly opened waters cause AA, whereas all other processes can only indirectly contribute to AA by melting sea-ice. We conclude that sea-ice loss is necessary for the existence of large AA and that models need to simulate Arctic sea ice realistically in order to correctly simulate Arctic warming under increasing CO2.
We found that large AA occurs only from October to April and only over areas with significant sea-ice loss in both observations and model simulations. AA largely disappears when Arctic sea ice melts away or is held fixed for calculating surface fluxes. Periods with large AA are associated with large sea-ice loss in model simulations, and models with bigger sea-ice loss produce larger AA. Increased LW radiation and latent and sensible heat fluxes from the newly exposed Arctic waters enhance surface and low-tropospheric warming and cause AA, whereas water vapor feedback, increased downward LW radiation, and other processes can only modulate the AA induced by sea-ice loss or indirectly contribute to AA by melting sea ice. Our results highlight the essential role of sea-ice loss in producing AA under GHG-induced global warming.
2. Given the report is tasked with reporting on a 1.5C warmer world (and perhaps whether much different from a 2C warmer world), they didn't really have much choice.
3. Is it a mistake? If they think it is a long way off (which unlikely with less than 1.5C warming implies), is it better to link it to some measure of global change rather than some specific years? Not sure on this, there is not much scope for 1.5C to arrive at noticeably different years but perhaps there is scope for 2C to arrive at different years depending what happens with future emissions.
Perpetual improvement goes on but I don't think this is what is being referred to here. I don't think the models are rerun just the output adjusted.
Fair point but what if essentially all the models show the same shape? Do you still think that is co-incidence or do you start to ponder if this shape is a reliable result from the models
What is this? Seems like you are trusting your gut instead of the result of modelling.
Should I put my trust in a projection based on a 4 parameter Gompertz equation?
Seems like you are trusting your gut instead of the result of modelling.
Quote1. Yes, certainly true if there is a redistribution of temperatures, but is this likely?There IS a redistribution of temperatures and it is mostly caused by Arctic sea ice loss.
If Antarctica cooled 10C and the Arctic warmed 10C the Arctic would melt with zero degrees of global warming.which is somewhat extreme and I fell into giving extreme response to this extreme.
10 and -10 nicely average to 0 and 10C guarantees an arctic sea ice melt down. I thought they were useful numbers to illustrate my point.Sure. But (if a serious reaction is allowed), the areas beyond to polar circle are much smaller than the rest of the world.
Should I put my trust in a projection based on a 4 parameter Gompertz equation?
Seems like you are trusting your gut instead of the result of modelling.
Any more than I should put my trust in the attached?
NASA seem to think soQuote1. Yes, certainly true if there is a redistribution of temperatures, but is this likely?
There IS a redistribution of temperatures
Should I put my trust in a projection based on a 4 parameter Gompertz equation?
Seems like you are trusting your gut instead of the result of modelling.
Any more than I should put my trust in the attached?
Probably not. However the Gompertz does a better job of fitting the observation data. Is that just coincidence? On the other hand, is there any reason to suspect a straight line decline? In any case, the largest rate of decline occurred over a roughly 10-year period, from 1998 - 2007. The decades both before and after have shown much less melt. Perhaps we are trying to apply a mathematical fit, where none exists. I think the ice will continue to decline, but in method between the two fits; less than the straight line, but more than the Gompertz. However, I could be just as wrong as the many others before who tried to predict the Arctic sea ice.
A 4 parameter gompertz is a far more complicated equation than the 2 parameter straight line. When allowed complexity rises the pool of possible functions that fit the observed data also rises, but the chance of such a fit being genuine and not a coincidence also falls, because of overfitting. Thus, when several equations fit the observed data reasonably, the least complex of them is more likely to be more correct, that's Occam's razor.
The outcome is certain catastrophe on an unprecedented scale.
Or maybe it is just me seeing this because I want to believe it as reinforcing my beliefs?
My difficulty with the IPCC report(s) comes from a different place. I cannot challenge the science and methodologies the scientists use. So on what basis can I criticise.
Simply put, because so far in each cycle they have been wrong, and each new IPCC cycle has built into it an unrealistic view of what the world is doing and will do.
Why,
- because the action taken by the world has not reduced CO2 emissions. They have increased.
- because the majority of new papers with new and improved data say things are worse.
- because the IPCC mandate is to look towards 2100.
- because ......
The proof is that the UN felt it necessary to issue the report to say to the world - you've got 12 years left or you/we are well are truly done for. And look at the reality, CO2 emissions are rising, carbon sinks are being degraded. We don't have 12 years. 2019 is not just a year wasted, it is a year that stole 2 years from that 12 years (if it exists at all).
So when will the Arctic go ice free? Sooner than when the IPCC says.
On the science, if the observations are not clear enough on an effect then there may still be an effect and it will almost certainly get worse with a +1.5C world rather than a +1C world. But if it is barely measurable is it really going to grow to be anywhere near of the order of civilisation collapsing effects?
I agree with most of what you have said but why would you choose to draw a distinction between 1C and 1.5C. We are going to blow past 1.5C as BAU is still the rule of the day. Would be shocked if we do not find ourselves in a 3C warmer world, minimum, by the end of this century.
I think that some of our most pessimistic commenters here on this forum have this as the context from which they make their comments. Having said this, I think we are probably 2 decades from having perennial BOE's.
the conclusion seems to repeatedly be that it isn't as bad as we feared.
Suddenly, the 2012 minimum does not look such an outlier.
QuoteBut they are better than nothing, you have to work with the tools you have got not the ones you would like, and the models show the same thing for 2020 2040 and 2060.
Let me be very clear about this. In the model that predicts a BOE by 2080, if you instantly remove the ice in 2020, 2040, or 2060 the ice immediately comes back. Well of course it does. The model is underestimating melt and/or overestimating freeze.
A wrong model is worse than nothing, if you make decisions according to the wrong model.
However, as the arctic keeps changing and showing scientist new secrets, I'm sure that better models will emerge.QuoteYou might want a newer source and better model, but basically tough: If it doesn't exist, then you are not going to get it. If there are two papers saying the same thing, then another paper is unlikely to be published unless it is saying something markedly different.
You don't think missing the first BOE by 4 decades (possibly more) is something markedly different?
Changing state of Arctic sea ice across all seasons
Julienne Stroeve and Dirk Notz 2018 Environ. Res. Lett. 13 103001
Abstract
The decline in the floating sea ice cover in the Arctic is one of the most striking manifestations of climate change. In this review, we examine this ongoing loss of Arctic sea ice across all seasons. Our analysis is based on satellite retrievals, atmospheric reanalysis, climate-model simulations and a literature review. We find that relative to the 1981–2010 reference period, recent anomalies in spring and winter sea ice coverage have been more significant than any observed drop in summer sea ice extent (SIE) throughout the satellite period. For example, the SIE in May and November 2016 was almost four standard deviations below the reference SIE in these months. Decadal ice loss during winter months has accelerated from −2.4 %/decade from 1979 to 1999 to −3.4%/decade from 2000 onwards. We also examine regional ice loss and find that for any given region, the seasonal ice loss is larger the closer that region is to the seasonal outer edge of the ice cover. Finally, across all months, we identify a robust linear relationship between pan-Arctic SIE and total anthropogenic CO2 emissions. The annual cycle of Arctic sea ice loss per ton of CO2 emissions ranges from slightly above 1 m2 throughout winter to more than 3 m2 throughout summer. Based on a linear extrapolation of these trends, we find the Arctic Ocean will become sea-ice free throughout August and September for an additional 800 ± 300 Gt of CO2 emissions, while it becomes ice free from July to October for an additional 1400 ± 300 Gt of CO2 emissions.
4.2. Stability of the ice cover
In addition to changes in the external forcing and internal variability, a self-amplification of the ongoing ice-loss could in principle have contributed to the rapid ice loss in recent years. Such self-amplification is usually discussed in the context of so-called tipping points or nonlinear threshold, which are often defined as processes in the climate system that show substantial hysteresis in response to changed forcing.
The best known example for such possible hysteresis behavior is related to the ice-albedo feedback mechanism: a reduced ice cover in a given summer will cause increased absorption of solar radiation by the ocean, contributing to further reductions in the ice cover. Such positive feedback loop can cause the irreversible loss of Arctic sea ice in idealized studies based for example on energy-balance models (see review by North 1984), and have hence been suggested to possibly be relevant also for the real world.
However, an analysis of the existing observational record and a substantial number of respective modeling studies with complex ESMs all agree that such a 'tipping point' does not exist for the loss of Arctic summer sea ice. For example, Notz and Marotzke (2012) found a negative auto-correlation of the year-to-year changes in observed September SIE. Hence, whenever SIE was substantially reduced in a given summer, the next summer usually showed some recovery of the ice cover. This was further supported by Serreze and Stroeve (2015). Such behavior suggests that the sea-ice cover is at least currently in a stable region of the phase space, as otherwise one would then expect that any year with a really low ice coverage should be followed by a year with an even lower ice coverage, driven by the ice-albedo feedback mechanism. As shown by Tietsche et al (2011), the contrasting behavior of the real ice cover can be explained by compensating negative feedbacks that stabilize the ice cover despite the amplifying ice-albedo feedback. The most important of these stabilizing feedbacks relates to the fact that during winter the ocean very effectively releases heat from those areas that became ice free during summer, thus over-compensating for any extreme ice loss in a preceding summer. Ice that is formed later in the season also carries a thinner snow cover and can hence grow more effectively during winter (e.g., Notz 2009). Stroeve et al (2018) suggest, however, that this stabilizing feedback mechanism is becoming weaker and weaker as Arctic winters become warmer and warmer. Increased winter cloud cover after summer sea ice loss as found by Liu et al 2012 also weakens the stabilizing feedback, as it reduces the loss of heat from the ocean surface.
The apparent mismatch of observations and complex model studies on the one hand, which both show no emergent tipping-point behavior of the ice loss, and studies with idealized models, which show tipping-point behavior, was resolved in a dedicated study by Wagner and Eisenman (2015). They were able to extend simplified models until their behavior agreed with more complex models. In doing so, they found that both spatial communication through meridional heat transport and the annual cycle in solar radiation are important for stabilizing the ice cover's response to changes in the external forcing.
Someone posted on this thread, and totally correctly, that there has been only one year where extent was less than 4 million km2, and that was 2012. Not only that, but 2012 extent minimum was, at 3.2 million km2, more than 800,000 km2 less than 2nd place 2016 (JAXA data).
That triggered my memory of a post I think by Tealight, in which he mentioned how when looking at area, we are much closer to a BOE. Time to have a look.
2012 NSIDC Area minimum was 2.25 million km2.
Not only that, 2016 area minimum was not 800,000 km2 greater than that, it was just 200,000 km2 greater at 2.45 million km2.
Not only that, if 2019 remaining area loss is average, minimum will come in at or a bit below the 2016 figure.
Suddenly, the 2012 minimum does not look such an outlier. The reason for the difference between extent and area comparisons? Dispersion. In 2016 the not so much greater area was spread out over a far larger extent.
My (joke?) prediction for the BOE on 23rd August 2027 suddenly looks more possible, or even conservative.
5. Accelerated sea ice loss during all months of the year is additionally driven by a lengthening of the melt season. As assessed for the Arctic as a whole through April 2018, melt onset is occurring 3 days earlier per decade, and freeze-up is happening 7 days later per decade (figure 3). Over the 40 year long satellite record, this amounts to a 12 day earlier melt onset and a 28 day later freeze-up.Not a conclusion, but the paper includes:
while the amount of ice exported through Fram Strait has increased over the satellite data, the increased ice export might instead be linked to the fact that that a thinner ice pack is more mobile (e.g. Rampal et al 2009, Olason and Notz 2014).A graph suggests a BOE about 2050, based on the final conclusion:
7. The primary cause of the ongoing changes in all months are anthropogenic CO2 emissions, with a clear linear relationship between sea ice loss and cumulative anthropogenic CO2 emissions in all months (figure 7). ...
Here's a good explanation of why there isn't expected to be a "tipping point" in the event of a BOE from a 2018 paper by Julienne Stroeve and Dirk Notz.
https://iopscience.iop.org/article/10.1088/1748-9326/aade56/meta (https://iopscience.iop.org/article/10.1088/1748-9326/aade56/meta)QuoteChanging state of Arctic sea ice across all seasons
Julienne Stroeve and Dirk Notz 2018 Environ. Res. Lett. 13 103001
... The annual cycle of Arctic sea ice loss per ton of CO2 emissions ranges from slightly above 1 m2 throughout winter to more than 3 m2 throughout summer. Based on a linear extrapolation of these trends, we find the Arctic Ocean will become sea-ice free throughout August and September for an additional 800 ± 300 Gt of CO2 emissions, while it becomes ice free from July to October for an additional 1400 ± 300 Gt of CO2 emissions.
I've been ruminating on this a bit...
For all of a BoE marking some sort of milestone in the Arctic, the impact of reduced summer (and Winter...) ice coverage is already making itself felt. In short, the difference between 2 million km2 extent and 1 million km2 extent won't be that significant from the standpoint of its effect on climate.
We're already seeing dire changes to the ecosystem and major impacts to year-round atmospheric circulation. I'm not seeing that changing much with a BoE, except on ramp up, in the manner of degree.
I've been ruminating on this a bit...
For all of a BoE marking some sort of milestone in the Arctic, the impact of reduced summer (and Winter...) ice coverage is already making itself felt. In short, the difference between 2 million km2 extent and 1 million km2 extent won't be that significant from the standpoint of its effect on climate.
We're already seeing dire changes to the ecosystem and major impacts to year-round atmospheric circulation. I'm not seeing that changing much with a BoE, except on ramp up, in the manner of degree.
You may be right, but there is another possibility and that is a flipping cold pole. Arctic-centred for now summer and winter, but starting to flicker to a Greenland centre in summer. That could be a whole lot flipping worse than a gradual ramp up.
Why agree with that methodology and not agree with this methodology?Here's a good explanation of why there isn't expected to be a "tipping point" in the event of a BOE from a 2018 paper by Julienne Stroeve and Dirk Notz.
https://iopscience.iop.org/article/10.1088/1748-9326/aade56/meta (https://iopscience.iop.org/article/10.1088/1748-9326/aade56/meta)QuoteChanging state of Arctic sea ice across all seasons
Julienne Stroeve and Dirk Notz 2018 Environ. Res. Lett. 13 103001
... The annual cycle of Arctic sea ice loss per ton of CO2 emissions ranges from slightly above 1 m2 throughout winter to more than 3 m2 throughout summer. Based on a linear extrapolation of these trends, we find the Arctic Ocean will become sea-ice free throughout August and September for an additional 800 ± 300 Gt of CO2 emissions, while it becomes ice free from July to October for an additional 1400 ± 300 Gt of CO2 emissions.
With current CO2 release, an additional 800 Gt takes 50 years (36 Gt annual release, 44% of which is retained in the atmosphere).
A good article though, and I would tend to agree with the conclusions.
Looking that far in the future is a mug's game.
So I think the methodology I used is junk, and so is the one by Stroeve / Notz. I am amazed they came up with that. Linear extrapolations to 2050? C'mon.
The abrupt changes in planetary climate that a BOE will bring are not magic. They are simple physics. The Earth has had a planetary refrigerator for likely millions of years. After a BOE that refrigerator fails and the NH will know true climate change. There won't be any denying because we'll be busy surviving.
I'm not arguing against logic here. It is frustrating to see how intelligent people who are aware of the role of arctic sea ice on atmospheric and oceanic patterns can't see the destruction that will ensue as the arctic disappears. The destruction has already started and the Arctic has barely begun to change.
But I may be wrong, so let's get to the science. Find me a paper that describes what happens after the first BOE, that doesn't ignore the ASI teleconections to the rest of the world and predicts a BOE much sooner than 2070.
Good luck with it.
While it is understood that changes happening within the Arctic do not stay there, it is less certain whether current Arctic warming is already driving an increase in storm frequency and extreme weather events across the mid-latitudes, including extreme heat and rainfall events, and more severe winters. The possibility of a link has driven an increased number of studies to examine linkages in more detail. A host of mechanisms and processes have been proposed and some consensus has emerged; namely that amplified Arctic warming, regardless of its driver, has increased geopotential height thickness (Francis and Vavrus 2012, Cvijanovic et al 2017), which in turn has weakened the thermal wind (Francis and Vavrus 2012, Walsh 2014, Pedersen et al 2016). It is not clear, however, how much these atmospheric changes have influenced the jet stream (Barnes 2013) or the influence on storm tracks and occurrence of blocking events (Zhang et al 2012, Barnes et al 2014, Barnes and Screen 2015). It is entirely possible that such a link exists, yet its manifestation in the real world is likely only of minor importance given the substantial year-to-year variability arising from internal variability of the climate system.
Looking that far in the future is a mug's game.
So I think the methodology I used is junk, and so is the one by Stroeve / Notz. I am amazed they came up with that. Linear extrapolations to 2050? C'mon.
I have to agree to some extent, but:
Shouldn't use such a linear trend for such a long way into future, unless it looks reliable?
Looks quite good for a longish period: 1953 to 2017. (Or have they used scale to minimise look of y axis variation?)
My issues with it are:
Last 10 years doesn't look as good and prior to that we were losing MYI which doesn't grow back each winter, from 2012ish onward or so the ice melted is largely growing back each winter. So could be much later than the relationship suggests.
OTOH if we stop coal mining rapidly, aerosol might decline while CO2 emissions keep rising changing previous relationship. Even without such a change, the aerosol effect is short term while CO2 cumulative emissions keep rising. This may cause more rapid drop than the relationship suggests.
Maybe these have cancelling effects and the linear relationship continues. More likely there are more such effects and they are unlikely to cancel so linear relationship does not continue, but if you believe that, why so linear over 1953 to 2017 period?
I do not think a linear trend extrapolated that far into the future is reliable. The slope appears to have changed several times over the decades. A Gompertz fit, as posted by others, appears to be a better fit, but it looks to flatten the curve too much.I was taught that the gompertz or S curve is used to represent the way an event happens. A classic example is expenditure on a construction project. Costs are low at the beginning, (design, approvals etc,) accelerate in the middle as main construction takes off and slows down with fiddly finishing work at the end. We used it in doing budgets for capital expenditure programmes.
Linear extrapolations to 2050? C'mon.
While natural variability may instead stabilize the ice cover for the next few years, the long-term outlook is disturbing. All models evaluated in the Intergovernmental Panel on Climate Change Fourth Assessment Report show declining September sea ice from 1953 to 2006.
While these models point to a role of GHG forcing, as a group they significantly underrepresent the observed trend [Stroeve et al., 2007]. The reasons for this underrepresentation remain to be fully resolved, but overly thick ice in several of the models provides a partial explanation. Given these conservative model results, along with the remarkable events of 2007, our view is that a seasonally ice-free Arctic Ocean might be realized as early as 2030.
Quote, our view is that a seasonally ice-free Arctic Ocean might be realized as early as 2030.
Quote, our view is that a seasonally ice-free Arctic Ocean might be realized as early as 2030.
New information causes new predictions to vary. What you are posting appear to show very little knee jerk reaction to new data and seems to me like a sign of good skill compared to wildly varying predictions on this forum. (Not sure if this is the message you are trying to convey.)
Trends over the past decade tell a different story.
New information causes new predictions to vary. What you are posting appear to show very little knee jerk reaction to new data and seems to me like a sign of good skill compared to wildly varying predictions on this forum. (Not sure if this is the message you are trying to convey.)
The trends over the last decades???
Anyone browsing the forum knows that things in the Arctic are getting progressively worse. The data says so itself ( unless you hide your head deep in the sand of denial and cherry pick data).
BZZT - ambiguous pronoun referents detected!
"It is worse than we thought" = the "we" refers to the climate science community.
"It isn't as bad as we feared" = the "we" refers to members of this board.
Both statements are thus true, because this board is much more alarmist that the community in general.
BZZT - ambiguous pronoun referents detected!
"It is worse than we thought" = the "we" refers to the climate science community.
"It isn't as bad as we feared" = the "we" refers to members of this board.
Both statements are thus true, because this board is much more alarmist that the community in general.
If you are not alarmed, you are in denial. The normal natural response of a person of science in the face of such monumental changes and uncertainty should be alarm.
If you are not alarmed you either don't really understand what is going on or fear psychology has taken over.
Members of this forum who peddle climate risk denial do not have the excuse of ignorance.
I have little tolerance for either alarmists or deniers, as both seem to be arguing from emotion rather than objective science. Both will cherrypick the data to show exactly what their psyche wants, instead of looking at the bigger view. The real kicker is that both of these extremists think that only they know the answers, and everyone else is of the opposite extreme.
Hey KK, you get my standard offer: Let's meet for lunch in 2030. If you're not fully alarmed, lunch is on me.
QuoteI have little tolerance for either alarmists or deniers, as both seem to be arguing from emotion rather than objective science. Both will cherrypick the data to show exactly what their psyche wants, instead of looking at the bigger view. The real kicker is that both of these extremists think that only they know the answers, and everyone else is of the opposite extreme.
Pssst. You are a denier and you just perfectly described yourself. You are in denial even about your denial. How do I know?
We should be alarmed BECAUSE of the uncertainties. The uncertainty surrounding climate change is already enough to bring the world to a screeching halt. If it wasn't for deniers like you speaking deliciously convenient poison it would've happened already.
It doesn't matter tho. It is a simple matter of time that you will be scared about climate change. It will only get worse and hit closer and closer to home.
Monuments should be erected for people like you, so that when SHTF and people are looking for scapegoats they know who to blame.
Sadly, people like you will likely just change tune and pretend you've been warning us about the dangers of climate change for years. People like you will turn to the scientists quoted by crandles and blame them for not crying wolf with wolves right in their faces.
Tough to be a climate scientist these days.
Climate change is deepening and the risks political leaders are taking is illogical from the perspective of the continuity of human civilization.
It's easy to demonstrate the deniers like Klondike are being disingenuous, but you have to choose the correct issues.
The timing of an ice free Arctic could very well be deferred until the latter half of this century.
We can not extrapolate the experience of the shallow Arctic perimeter to the deep Central Basin.
If we treat the Central Basin as a separate entity as we should, there is no trend line supporting a likely BOE before 2030.
It may very well happen sooner than 2030, but it will be a function of weather variation.
The uncertainty that Archimid speaks to is indeed justification for rational fear. We would never get on a plane that had a 5% chance of crashing and killing us. There is no logic to support pushing the system to a point which has a meaningful possibility of causing global catastrophe.
We know enough to understand that the possibility of global catastrophe is real and too high.
If we treat the Central Basin as a separate entity as we should, there is no trend line supporting a likely BOE before 2030.
The trends over the last decades???
Anyone browsing the forum knows that things in the Arctic are getting progressively worse. The data says so itself ( unless you hide your head deep in the sand of denial and cherry pick data).
I'll show you what anyone looking at what the data say can see.
I attach a chart which shows average volume (piomas) for the first 6 months of the given year. I use this because we already have this for 2019.
I also put in a polynomial forecast. I also attach (second chart) the 10 year rate of change which peaked 2007-12 and has been around the average of 1995-2005 in the past few years.
I also attach (third chart) the average volume for july-aug-sept-oct. As you can see, there has been really not much change since 2010.
Yes, volume is shrinking during winter. Yes, eventually we will lose all Arctic ice - no reason to argue with that. But looking at these pictures you could understand that the Center still holds and it is impossible to know how long it will, it might vanish in 2020 or hold out until 2050 - since summer volume hasn't changed for a decade, and there is a reason why: bathymetry. Our long-term models for forecasting ice clearly suck, so no surprise scientists also try to use various statistical projections (linear or any other they seem fit).
What we can see is that during the past 10 years winter volume and extent are shrinking and the surrounding oceans are warming, but still, the Center holds. Eventually the seas around the CAB will be strong(warm) enough to destroy it, but based on the data I believe it is impossible to say when it will happen.
It is touch to be a climate scientists. The deniers roast them for spreading false information, while the alarmists deride them for being soft on scaremongering. Yes, there is much uncertainty. But that is no reason to cower in fear. Not everyone is a metathesiophobiac.
This can be clearly seen in your graph. From 1979 to 2006 CAB melting was steady. Then in 2007 a state change occur where annual volume loses increased significantly. During this time multiyear ice was destroyed. Such volume loses peaked in 2012 and since then have been climbing steadily again, towards the next step change.
But this is not all, the shape of the maximum trend line also has consequences for the losses line. When there was a fast rate of max volume decline, this translates into more/faster open water formation and more albedo feedback so the losses increase at a faster rate. However, now that the fast rate of max volume decline has gone away, this effect also goes away and the rate of increase in losses should also be expected to be slower. (That isn't even considering whether losses decline as the ice shrinks to areas that are harder to melt)
The choice and arrangement of facts (or, alternatively, 'facts') are part of rhetoric, as the ancient Greek already knew.
Archimid, will you calling Rich a denier also, as he thinks a BOE is unlikely by 2030 also?
But this is not all, the shape of the maximum trend line also has consequences for the losses line.
....
I think the opposite is true. Near record low minima, year after year, has meant more open water at the beginning of the arctic night, with vastly increased outgoing radiation to space in the arctic night. Yet, the minimum has been trending down, despite this strong negative feedback.
By end of winter, there's still a (thinner) snow+ice cover over most of the traditionally ice-covered arctic, presenting a fairly typically low albedo for the spring high-insolation period. And yet, losses have been trending to greater values, despite this negative feedback.
There's good reason to believe the observed trends will continue, as GHG levels continue to increase and sub-surface ocean warmth continues to increase.
First the maximum volume line. So instead of one straight line we should have shallow decline, steep decline then shallow decline again. Fast rate being thick MYI disappearing and not coming back. Now this has gone there is more FYI which mainly reforms each winter so a shallower decline line for the maximum. This pushes the date of the intersection to later dates.
However, now that the fast rate of max volume decline has gone away
this effect also goes away and the rate of increase in losses should also be expected to be slower. (That isn't even considering whether losses decline as the ice shrinks to areas that are harder to melt)
Actually, the regional PIOMAS data that Wipneus posts starts on the year 2000. I merely used the whole data set. Where did you get regional PIOMAS from 1979?
Actually, the regional PIOMAS data that Wipneus posts starts on the year 2000. I merely used the whole data set. Where did you get regional PIOMAS from 1979?
It's on the piomas site, I just downloaded it
For the sake of identifying trends, the peripheral seas very much need to be left out, as even before the current decline, they tended to melt out entirely over the melt season and buffer the numbers in ways that mask the actual shift in system behavior.Actually, the regional PIOMAS data that Wipneus posts starts on the year 2000. I merely used the whole data set. Where did you get regional PIOMAS from 1979?
It's on the piomas site, I just downloaded it
Archmid's CAB excludes the peripheral seas. Your PIOMAS data includes them.
Umm, I don't really believe this graph as the green and purple trend lines don't cross in future and with continues GHG emissions I believe they will. Also sorry about the trendlind being extended outside the range they are meant to apply to which makes graph horribly messy.I think the problem lies in the fact we are trying to collapse probability in a 3 dimensional system over time down to 1 absolute scalar value.
<snippage>
These need more data to verify, but so far the data suggests what?
I try to capture what you are talking about
I think that starting the purple line in 2013 is a better choice than 2011,
Actually, the regional PIOMAS data that Wipneus posts starts on the year 2000. I merely used the whole data set. Where did you get regional PIOMAS from 1979?
It's on the piomas site, I just downloaded it
Archmid's CAB excludes the peripheral seas. Your PIOMAS data includes them.
The CAB has about 20% of the area of the Arctic Ocean and
- about 50% of the volume at maximum,
- about 90% of the volume at minimum.
and....
What story do you want ?
Choose your trend line and any future is yours.
No. I only used CAB volume (they have it on their site in the monthly file broken down by seas),
How long this state lasts is impossible to say.
Given that you are risking all our lives ...
QuoteHow long this state lasts is impossible to say.This is an update on this year losses for the CAB.
What El Cid and Crandles are doing is a version of "no warming since 1998". Their arguments are not a product of science or logic. Their arguments are a product of freezing fear that stops them from seeing evidence that confirms their fears.
If they are advocating no action against climate change and no alarm, they better have a damn good case, because the evidence is reason for great alarm.
Denying the risk of climate change,I'm not seeing anybody denying the risk of climate change?
particularly, denying the risk to all our lives that A BOE presentsWhat risk does a BOE present to me above and beyond the general risk of continued AGW to my life? None in my opinion.
is placing our lives at risk.So I'm putting my (and your) life at risk by denying that BOE presents a risk above and beyond continued AGW?
This is not hyperbole, although it sounds like it.Sounds like it, looks like it.
It is the simple fact.When your hyberbolista starts claiming to know "the simple fact" about something then I think it's time to reach for the 'brellas.
I'm not seeing anybody denying the risk of climate change?
What risk does a BOE present to me above and beyond the general risk of continued AGW to my life? None in my opinion.
So I'm putting my (and your) life at risk by denying that BOE presents a risk above and beyond continued AGW?
Sounds like it, looks like it.
When your hyberbolista starts claiming to know "the simple fact" about something then I think it's time to reach for the 'brellas.
Denying the risk of climate change, particularly, denying the risk to all our lives that A BOE presents is placing our lives at risk. This is not hyperbole, although it sounds like it. It is the simple fact.
I'm not sure if you are reading what I wrote? I do not think that BOE causes any risk to me or mankind above and beyond the general risk of continued AGW.QuoteI'm not seeing anybody denying the risk of climate change?
You can't see anyone denying risk of climate change? Here. Read your own words.QuoteWhat risk does a BOE present to me above and beyond the general risk of continued AGW to my life? None in my opinion.
I mean, you say that you don't see anyone denying risk in the same post that you deny the risk. If you can't see it when you deny it, how do you expect to see it when others deny it? See, this is not science or logic. These types of contradictions are products of fear psychology.
Where I disagree with you is strictly regarding the focus on imminent BOE.
Where I disagree with you is strictly regarding the focus on imminent BOE. The point that El Cid is making regarding the fundamental difference between CAB and rest of Arctic is salient. Focusing on CAB trends alone, we do not get a BOE by 2030 or 2040.
We give ammo to the deniers like KK by advancing claims such as BOE before 2030 which aren't empirically supported.
There are many better arguments in support of impending catastrophe than BOE.
I'm not sure if you are reading what I wrote? I do not think that BOE causes any risk to me or mankind above and beyond the general risk of continued AGW.QuoteI'm not seeing anybody denying the risk of climate change?
You can't see anyone denying risk of climate change? Here. Read your own words.QuoteWhat risk does a BOE present to me above and beyond the general risk of continued AGW to my life? None in my opinion.
I mean, you say that you don't see anyone denying risk in the same post that you deny the risk. If you can't see it when you deny it, how do you expect to see it when others deny it? See, this is not science or logic. These types of contradictions are products of fear psychology.
I've seen nothing that indicates that the huge risk involved in continued AGW is in any significant way increased (or decreased) by a BOE.
Does that mean that I deny that there is a risk involved in continued AGW? Of course not. Stop spouting nonsense my dear man!
I'm not sure if you are reading what I wrote? I do not think that BOE causes any risk to me or mankind above and beyond the general risk of continued AGW.
I've seen nothing that indicates that the huge risk involved in continued AGW is in any significant way increased (or decreased) by a BOE.
Does that mean that I deny that there is a risk involved in continued AGW? Of course not. Stop spouting nonsense my dear man!
What total nonsense.
I'm not sure if you are reading what I wrote? I do not think that BOE causes any risk to me or mankind above and beyond the general risk of continued AGW.
You are not reading what you wrote. A BOE presents a much greater risk than the generalized risk of AGW. you are denying it does, yet you think you are not.
What total nonsense.
A BOE is at most something that gets in the news. AGW is already killing people and has the potential to totally wreck our civilization.
And don't think that I think that losing Arctic Sea Ice is not a huge danger to us all. It has consequences that are already visible, and will only get worse.
I did not say that a BOE is a huge danger. On the contrary, I think I made it abundantly clear that I think a BOE is a non-event.QuoteWhat total nonsense.
Sigh. how does this:QuoteA BOE is at most something that gets in the news. AGW is already killing people and has the potential to totally wreck our civilization.
does not contradict this:QuoteAnd don't think that I think that losing Arctic Sea Ice is not a huge danger to us all. It has consequences that are already visible, and will only get worse.
A BOE is a huge danger for us all but at most, it is something that gets in the news.
Please explain.
As it pertains to BOE, you are not a denier KK. I actually agree with you here.
The denier label speaks to your general contribution at ASIF.
If you check the polls taken here, the expectation of the voting members of ASIF is BOE in the near future. Much sooner than CAB trend lines would suggest.
In a sense, I think the ASIF community hands the deniers an easy win by engaging in so much speculation about imminent BOE. If I were a denier with an agenda of maintaining BAU, this is where I would want the conversation to be. This is where I would show up and amplify the denier message of uncertainty.
I generally consider it a waste of time to argue with deniers. The consequences of our climate crisis generally doesn't apply to them, and so the only risk they are concerned with is monetary, and not risk to human life.
More importantly, what is the greatest risk to human life as a consequence of climate change?
Changes in rainfall patterns, of course.
Humans need water for consumption, for food, for cleaning, etc.
We are already seeing drastic changes in our rainfall patterns, and you cannot pretend a BOE won't be a major factor, as the hastily melting Arctic Sea Ice already has.
We're already seeing how its effecting political stability in regions that have gone very dry, with migration gradually increasing. We're also seeing the consequences of too much rain in North America this year, with terrible consequences to farmers' growing season.
Are you, Archimid, denying that ongoing AGW is causing, and will cause, major disruptions and loss of life?
Got it Archimid. You've said your piece.
If the arctic ice collapses and the climate breaks down over the next few years, you'll be on record.
I don't think there is any reason to keep saying it.
Got it Archimid. You've said your piece. If the arctic ice collapses and the climate breaks down over the next few years, you'll be on record. I don't think there is any reason to keep saying it.
It can't possibly be that bad... right? Wrong. It is that bad, and if it isn't, we should assume it is because it is going to be very damned bad.
A BOE of a day won’t severely disrupt climate. A BOE of a month might. A BOE of a season certainly will.I agree that GW (which is all AGW) is bad and is getting worse, and deserves our shouting from the rooftops. I'm not certain about what drives what (systems are interconnected and complicated), so a one-day BOE will, I believe, be associated with a noticeably more disrupted climate then we have now, and a month-long BOE will be associated with noticeably more disrupted climate than when we had the first one-day BOE.
I agree with your post, until you mention uncertainty. I disagree that the denier message is uncertainty.
<various snippages>On this, I have to say I'm in concord with binntho. For all of our wrangling over what is an entirely symbolic metric threshold (1000km3 of ice), it is an effect, rather than a cause.
I did not say that a BOE is a huge danger. On the contrary, I think I made it abundantly clear that I think a BOE is a non-event.
The ongoing loss of Arctic Ice is not a BOE, and it is the ongoing and continuing loss of Arctic Ice that is already having dangerous effects and will only get worse as more ice is loss. Irregardless of an eventual BOE.
For all of our wrangling over what is an entirely symbolic metric threshold (1000km3 of ice), it is an effect, rather than a cause.
That cause - general heating of the Arctic climate - is already generating cascading failures in the biome and through teleconnections wreaking havoc all across the northern hemisphere.
This will no doubt scale with time, but reaching the specific above mentioned threshold will not mark nor prompt any abrupt transition that isn't already well underway, nor already having pronounced effects on the world.
Gentle sentients, can we please return to the discussion of science rather than tearing at each other?
Sorry JD, but in this you are wrong. A BOE is not symbolic. It used to be just effect, but it is now both cause and effect.I'm not arguing that a lack of ice won't change the Arctic. Ice loss will and has been doing that.
CO2 alone is not causing this. Not anymore. The system is now feeding of itself.
Neither I nor binntho suggest otherwise and agree. Mostly I think we're saying that the harm currently being done, has been done, is greater than a single BoE event would be. Our conclusion is, a BoE event won't be a trigger on its own. It will be adding to momentum already in place. In short, more a result, than a specific cause.
In argument to support that, you need go only as far as the current state of the northern hemisphere jet stream. It will continue to degrade as the Ferrel, Hadley and Arctic cells collapse, as a direct result of heating already in place and continuing at high latitude.
Sorry JD, but it is completely and absolutely wrong that a BOE will not be a significant event. I have no clue how you even arrive to that conclusion as it is nonsensical to me. If there is no ice to melt, then the Arctic will warm, significantly, the oceans will mix, humidity parameters will go out of whack.<SMH> This, my friend, is hubris, flavored with a touch of conceit.
I'm sorry that I have to resort to emotional appeals but you all are ridiculously wrong about this. It feels as If I'm debating flat earthers, not rational intelligent people.
I think maybe Archimid has the mental image in his head of a kettle of water on the stove with a lump of ice in the middle. Not much will happen to the water untill the ice is gone.
I don't know how far you can extend this metafore to the arctic. Is the heat that's entering via the Chuckchi dissipating towards the cab ? Would the Chuckchi be 20 degrees allready if there were no ice in the cab ?
I'm sorry that I have to resort to emotional appeals but you all are ridiculously wrong about this. It feels as If I'm debating flat earthers, not rational intelligent people.
What I (and I expect binntho) are suggesting is, (1) we don't think it will happen all at once.
(2) the cumulative losses we have seen since around 2007 have contributed at least as much to upsetting the system as a BoE would and
What I hear is, you are so caught up in your conclusion, you are failing to hear or understand the arguments being made contrary to it, and by extension making rather extreme assignations against people who've been fighting to save exactly this ecosystem for a very long time.
Strange this hyperdenialism that seems to have gripped some people.
Global warming is already killing people and changing whole countries, being a significant factor in the ongoing war in Syria and the biggest risk to national security worldwide as has been comfirmed by, amongst others, the US Army.
The danger to global food production that global warming poses is huge, massive, scarily gigantic.
Denying this very real and present danger by clamoring about a purely hypothetical BOE Harmageddon is - denialism.
Perhaps we could try and put numbers on them a bit like the Richter logarythmic scale for earthquakes. As in "Trump elected president" is a 2 but "Trump goes to war with Iran" is a 3 (effectively a 10 times bigger catastrophy......
You are confusing the energy in each whole number (31.4x) and the wave amplitude (10x).
Perhaps we could try and put numbers on them a bit like the Richter logarythmic scale for earthquakes. As in "Trump elected president" is a 2 but "Trump goes to war with Iran" is a 3 (effectively a 10 times bigger catastrophy......
FYI - Each point of the Richter Scale is not a 10X increase. It is logarithmic, but 2 points on the scale is 1000x. One point on the scale is the square root of that or roughly 31 4x.
Weird scale.
Exactly. We seem to be in total agreement. Strange that you find that obnoxious.Strange this hyperdenialism that seems to have gripped some people.
Global warming is already killing people and changing whole countries, being a significant factor in the ongoing war in Syria and the biggest risk to national security worldwide as has been comfirmed by, amongst others, the US Army.
The danger to global food production that global warming poses is huge, massive, scarily gigantic.
Denying this very real and present danger by clamoring about a purely hypothetical BOE Harmageddon is - denialism.
This is obnoxious. The current gradual loss of Arctic Sea Ice is linked to the significant changes in weather and rainfall patterns. It is precisely one of the mechanisms by which Climate Change is effecting us soonest.
Looking at Arctic Sea Ice volume charts, we are not far off from a mostly ice-free Arctic. Not sure why you are so eager to argue semantics and technicalities. You have no argument if you're trying to say this isn't happening to the Arctic Sea Ice, or that the consequences won't get worse as we lose more ice.
Again more simply... A nearly ice-free Arctic is likely to make the current changes to rainfall patterns even worse, and our technical definition of a BOE may be overly-conservative a measure. This is going to destabilize entire countries, and bring much human suffering.
Perhaps it would help if Archimid laid out his reasoning, preferably supported by facts and figures and even (one hopes) a peer-reviewed paper or two.
Archimid, please explain: Why do you think that a BOE will be such a cataclysmic catastrophe?
How can anybody claim that a single event, albeit important, that does not really change anything can be a bigger catastrophe than what has been happening all the time leading up to that event?
Perhaps it would help if Archimid laid out his reasoning, preferably supported by facts and figures and even (one hopes) a peer-reviwed paper or two.
Archimid, please explain: Why do you think that a BOE will be such a cataclysmic catastrophe?
You are arguing that the climate conditions are bad, partly because the missing ice, but then you argue that if you remove all the ice it doesn't get worse. It doesn't even make sense.
Ok so who has the burden of proof? The one that's making an extraordinary claim.Yours is obviously the bigger claim.