Loss Of Arctic Sea Ice

[Gray-Wolf]

Youth of Arctic sea ice revises predictions of ice-free pole

As a result of the dramatic declines in Arctic sea ice during the last few years, researchers are now focusing on the age and thickness of the remaining ice in order to refine predictions of when the Arctic may go ice-free.

By John Timmer | Last updated April 8, 2009 6:16 AM

Over the past several years, the amount of sea ice in the Arctic Ocean during the summer months took an unexpected plunge, dropping below the levels predicted by many models. As a result, the prospect of an ice-free summer in the Arctic, which would have consequences for everything from the local ecology to global trade, is something the research community is studying intensively. That work is leading to a new understanding of how the age of the ice combines with natural variability to produce sudden changes like the ones we've observed recently.

Two recent reports have focused attention on the state of the Arctic sea ice. On Monday, the National Snow and Ice Data Center announced that the annual summertime decline of Arctic sea ice had started, and issued its annual analysis of the recent dynamics in the Arctic. That analysis followed hot on the heels of a paper that predicts that the Arctic will be effectively ice-free in roughly 30 years. I'll combine those reports with information from a talk given by the Jean-Claude Gascard of the Université Pierre et Marie Curie, who spoke at this year's American Association for the Advancement of Science meeting.

First, the current state of the ice. According to the NSIDC, the end of last summer's melt season left Arctic ice cover near the historic lows of the previous year, but the open water froze quickly, leading to a peak level somewhat above that of recent years. The winter's peak ice coverage came earlier than usual, but levels have remained fairly stable so far this spring, leaving ice coverage below historic averages, but well above the amount that's been typical over the last several years.

The expectations for this summer, however, aren't significantly different from those of other recent years. To understand why, you have to consider the age of the ice. In the Arctic, ice that survives a single season puts on weight, growing thicker; that thickness makes it far less likely that the ice will melt over the course of the summer. As shown in the graph below, the amount of multi-year ice has plunged in recent years, having been replaced primarily by one-year old ice that's thinner and more prone to melting. Note that the graph represents the percent of total ice; since the total ice has dropped in recent years, the absolute numbers on this loss are a bit larger.

This past year saw a continuing decline in multi-year ice, but a rebound in ice that's survived two seasons. The reasons for this can be seen when the geographic distribution of the ice is examined. The older ice has largely been pushed against Greenland and the Canadian Arctic where, each year, a fraction is pushed out past the northern tip of Greenland, where it flows into the North Atlantic and melts. The better freezing conditions of the past year have meant that two-year-old ice has largely extended out towards the pole from Canada. These dynamics mean that it will take several years of similar conditions before multi-year ice can start recovering what's lost to the Atlantic.

The emphasis on the thickness of multi-year ice and seasonal variations feeds nicely into the modeling paper, which was published in Geophysical Research Letters. The authors of the paper evaluated a suite of 23 climate models for their ability to roughly match the measured behavior of the Arctic sea ice during the 20 years following 1980. They wound up with six models that seemed to be getting the sea ice right, and noted that half of these "include a multiple sea ice thickness distribution as part of a sophisticated sea ice physics and dynamics package," something that's only present in the most recent generation of climate models.

The authors ran these models forward from the present, using two different IPCC climate projections, and determined how long it took for the summer ice to drop to a million square kilometers, which is the margin they consider effectively ice-free. This point was reached when the remaining ice was anchored to the Canadian Arctic, the current site of the oldest and thickest ice; the rest of the Arctic ocean was open water. Overall, the mean interval for this to happen is 32 years.

The authors note a couple of things about their model runs. For starters, the decline in sea ice doesn't occur in the absence of anthropogenic forcings, which they term a "necessary condition." Indeed, at AAAS, Gascard indicated that, combined, anthropogenic forcings and changes in the albedo caused by the loss of reflective ice account for about 85 percent of the recent temperature change in the Arctic.

But, although anthropogenic forcings are a necessary precondition to cause the loss of ice, natural variability still plays an essential role in controlling the dynamics. The models indicate that it would have taken decades longer to reach the levels of sea ice seen in 2007 in the absence of specific weather conditions, such as a series of consecutive warm years and winds that drove some of the sea ice into the Atlantic. The authors also state that, once sea ice levels reach their current levels, they tended to decline rapidly in all of the models.

These results suggest that a confluence of factors, some stochastic, combined to cause the sudden decline of Arctic sea ice in recent years, so scientists could be forgiven for being surprised by its speed. Moving forward, however, the results suggest that keeping a careful eye on the age of the ice, as well as its extent, may help us stay on top of future developments.

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We seem to be having a few 'unrelated discussions' over on J1's Arctic sea ice thread so I thought I'd see if we needed another to discuss the broader topics the loss of sea ice brings to the fore.

[Gray-Wolf]

It would seem that we don't. If there's a mod in the house maybe we could lock and bin this?

[Admiral_Bobski]

Don't lock and bin it just yet - I'm trying not to get too involved in anything at the moment because I'm off on my holidays in a couple of days, but I might have something to say when I get back in a week (in fact I'm bound to have something to say - you know me: verbal diarrohea!).

CB

[Gray-Wolf]

I'd love to have some of the natter from both the Sea ice thread and General Climate change (relating to the Arctic ) over here!

To me it seems that the place to look for climate change evidence is across the poles (where it was supposed to manifest first) and then try and see if it can all be natural or whether we truely have impacted our planets climate system to the point where we are helping augment our natural cycles to a place beyond a point of no return (to the type of climate we evolved in).

[Admiral_Bobski]

I'd love to have some of the natter from both the Sea ice thread and General Climate change (relating to the Arctic ) over here!

To me it seems that the place to look for climate change evidence is across the poles (where it was supposed to manifest first) and then try and see if it can all be natural or whether we truely have impacted our planets climate system to the point where we are helping augment our natural cycles to a place beyond a point of no return (to the type of climate we evolved in).

I think that's a good idea, and it stops the Arctic Ice thread (which is more of a monitoring thread) from getting cluttered up with off-topic discussion.

I'd love to start right now, but I don't have time unfortunately Holidays always seem so far away until 2 days before when you suddenly realise you've not got anything ready and you have to rush round like a lunatic!

So I'd better get on with my lunacy :blink:

I'll be back in about a week!

CB

[Gray-Wolf]

"........I've been thinking along those lines for a while now.

As I understand things the Arctic Amplification only concerns itself with the top layers of the arctic Ocean (it doesn't need to loose the summers heat all the way down to the sea bed just enough to let the surface ice start to form).

In fact I'll take this over to the 'other place' (the arctic natter thread) ...."

The thing that had me wondering was that recent 'ICEsat' paper on ice thickness over the past few years.

Whist noting a thinning of the remaining 'Old perennial' it showed no thickening of the 'new' multiyear that has grow over the period of the study.

The only way I could figure this was that on re-freeze only the upper sections of the ocean were giving up their heat via the Arctic Amplification and deeper down temps are maintained (above the temp that used to occur in those areas). If ice thickens it pushes deeper into the water and is ablated by this lower horizon of warmer water, the perennial is already forced into this deeper 'warm zone' and so melts through winter and summer giving us the losses we see there.

In Antarctica we have seals with thermometer bath caps underneath the ice shelfs/sea ice but I don't know if we have any data on the temp horizons under the polar ice?

If we know we had a 'mini-melt' that was slowed by the globally dimmed period would the 'dimmed period' have been long enough to allow the arctic waters to chill back down to there post warming horizons or, as sub data suggest, did it maintain and continue to erode the old perennial ice through this period?With the renewal of the warming we would witness an acceleration of the melt across the Arctic as the bottom waters were still carrying some of the pre-1940 heat burden so allowing even greater impacts to present over a shorter time frame.

Time and again we hear that 'warm water' (wind driven or extensions of existing currents) being primarily responsible for ice sheet melt/glacial collapse/ice thickness loss. Have we ,above and beyond natural cyclical variation, allowed the oceans to warm and some of this 'extra warmth' been responsible for the ice erosion we see today?

[Methuselah]

I've been thinking too, so beware!

I'm thinking that the ice-melt process itself acts as a natural negative-feedback mechanism that serves to ameliorate warming. Assuming it does act this way, what'll happen when there's no more ice left to melt?

For the moment though, I'm not interested in WHY the ice was/has been/is in the process of melting.

[Gray-Wolf]

I've been thinking too, so beware!

I'm thinking that the ice-melt process itself acts as a natural negative-feedback mechanism that serves to ameliorate warming. Assuming it does act this way, what'll happen when there's no more ice left to melt?

Tis a worry that.

When the ice in my Malt melts then the Malt starts to warm faster than it did when the ice was there.With the loss of all that perennial and the thinning of the remainder you have to wonder at the potential for the worlds 'air conditioner' to perform at it's optimum for much longer.

I kinda think that once we've lost that then all other natural cycles will be impacted with the cooling phase being moderated and the \warming phases being augmented.

Alongside the sea ice we have the land and it's ice sheets and permafrost.Once the cooling influence of the sea ice is removed then what of these (the impacts are able to be measured over 1,500km inland once sea ice is removed)?

http://www.terradaily.com/reports/Global_Warming_Our_Best_Guess_Is_Likely_Wrong_999.html

In the past we can see that CO2 has it's role to play in warming the planet but the planet itself appears to do the majority of it's warming itself and probably (I feel) by the removal of the negative feedbacks which help keep temperatures stable.

[Solar Cycles]

Tis a worry that.

When the ice in my Malt melts then the Malt starts to warm faster than it did when the ice was there.With the loss of all that perennial and the thinning of the remainder you have to wonder at the potential for the worlds 'air conditioner' to perform at it's optimum for much longer.

I kinda think that once we've lost that then all other natural cycles will be impacted with the cooling phase being moderated and the \warming phases being augmented.

Alongside the sea ice we have the land and it's ice sheets and permafrost.Once the cooling influence of the sea ice is removed then what of these (the impacts are able to be measured over 1,500km inland once sea ice is removed)?

http://www.terradail..._Wrong_999.html

In the past we can see that CO2 has it's role to play in warming the planet but the planet itself appears to do the majority of it's warming itself and probably (I feel) by the removal of the negative feedbacks which help keep temperatures stable.

I wasn't going to venture into ths thread, but I did, and now I'm here I have to comment on this scaremongering nonsense. Gw as the arctic not been ice free before? Off course it as! All these assumptions are becoming tiresome. Please GW speculate all you want. But for the love of god, can we just state on your posts, that all your assumptions are just that!

[Methuselah]

I wasn't going to venture into ths thread, but I did, and now I'm here I have to comment on this scaremongering nonsense. Gw as the arctic not been ice free before? Off course it as! All these assumptions are becoming tiresome. Please GW speculate all you want. But for the love of god, can we just state on your posts, that all your assumptions are just that!

You don't seem to get the gist, Solar???

Most, if not all, of our 'assumptions' are qualified by such amazingly illuminative expressions as 'I think', 'IMO', 'I wonder', 'I'm assuming' etc. If they're not made quite so explicit, all you need do is to take note of the context.

Why don't you enter into the discussion yourself? I'm sure you have some useful knowledge of negative feedback that you'd like to share with us? It's not a closed shop!

[Iceberg]

The artic has not been free of ice whilst the continents and ocean currents have been in the position they are now.

I think my views on this are well known, A big dose of natural al la Polyakov and a sizeable dose of GHG warming to push the arctic, unfortunately into a spiral of decline,such that it will be ice free, absorbing alot more warmth into the arctic ocean in the summer.

The warming of Greenland in the summer will then accelerate with melt rates across Greenland inceasing by maybe 500 to 1000%

This is of course pure opinion.

[Gray-Wolf]

Australian study reveals ancient secrets to climate change www.chinaview.cn 2009-07-23 18:37:40

CANBERRA, July 23 (Xinhua) -- A groundbreaking study released in Australia on Thursday recorded sea temperatures over millions of years that could reveal the secrets to the climate change.

Australian scientist Sindia Sosdian and research partner Yair Rosenthal studied the shells of tiny sea creatures for more than three years to examine major climate shifts over the past 3.2 million years.

The research recorded two major cooling periods over that time -the first about 2.7 million years ago when a drop in greenhouse gases is believed to have caused the formation of giant ice sheets in the northern hemisphere.

Sosdian believed that the information could help climate change specialists better interpret ancient shifts in temperatures.

It could also hold the key to predicting future changes with more clarity.

"That's an interesting finding and that's something .. new to the scientific community," Sosdian said.

"Now they (climate change scientists) can ask what's caused it and why do we see these interesting changes."

Sosdian indicated the ice sheets had a much bigger impact on global temperatures than first thought. "Our finding suggests that the way ice grows and retreats - its physical dynamics - played a significant role in hastening climate transitions the second time around," she said.

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Just as an add on to my last post.

Once temps start to rise it must surely take energy and time to melt out the ice pack but then ,once it has gone (along with any stabilising effect it may have on global temps) what then?

I do not think we gain any insight by trying to blame the failure of current CO2 levels to impact temps like it has in the past whilst we still have our 'air conditioner' spluttering on.If, once it has failed completely (and the energy used to melt it by raising ocean temps/atmospheric temps) then what happens? Can anyone suggest any type of comparable negative feedback mechanism on the planet to rival the job of the pole (temperature and albedo wise)?

[Methuselah]

Australian study reveals ancient secrets to climate change www.chinaview.cn 2009-07-23 18:37:40

CANBERRA, July 23 (Xinhua) -- A groundbreaking study released in Australia on Thursday recorded sea temperatures over millions of years that could reveal the secrets to the climate change.

Australian scientist Sindia Sosdian and research partner Yair Rosenthal studied the shells of tiny sea creatures for more than three years to examine major climate shifts over the past 3.2 million years.

The research recorded two major cooling periods over that time -the first about 2.7 million years ago when a drop in greenhouse gases is believed to have caused the formation of giant ice sheets in the northern hemisphere.

Sosdian believed that the information could help climate change specialists better interpret ancient shifts in temperatures.

It could also hold the key to predicting future changes with more clarity.

"That's an interesting finding and that's something .. new to the scientific community," Sosdian said.

"Now they (climate change scientists) can ask what's caused it and why do we see these interesting changes."

Sosdian indicated the ice sheets had a much bigger impact on global temperatures than first thought. "Our finding suggests that the way ice grows and retreats - its physical dynamics - played a significant role in hastening climate transitions the second time around," she said.

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Just as an add on to my last post.

Once temps start to rise it must surely take energy and time to melt out the ice pack but then ,once it has gone (along with any stabilising effect it may have on global temps) what then?

I do not think we gain any insight by trying to blame the failure of current CO2 levels to impact temps like it has in the past whilst we still have our 'air conditioner' spluttering on.If, once it has failed completely (and the energy used to melt it by raising ocean temps/atmospheric temps) then what happens? Can anyone suggest any type of comparable negative feedback mechanism on the planet to rival the job of the pole (temperature and albedo wise)?

Ian, my previous attempt at an answer vanished into the ether, so here's a truncated version:

As you know, I am highly sceptical of doomsday scenarios; but this one needs thinking about, IMO: if all the ice were to melt, I can't see what will act as a natural 'refrigerator'?

I'm sorry, but my brain is addled with vodka...

[Iceberg]

I agree Pete and I've only had Beer.!

I can see global temps rising by as much as 2C with the disapperance of the the arctic ice. I think trying to model this though is very difficult, if not impossible with our current understanding of climate and rightly it's effects are ignored by the IPCC as there is just tou much uncertanity at present.

[Gray-Wolf]

All I know is that many of my bikes fell foul of a small component failure. Some I spotted others cost me an engine. No matter how small a part is it's role is as crucial as the biggest in the smooth running of the engine. Sea ice is no 'small' component of the climate 'engine'. Remove it and what?

[Gray-Wolf]

And today, without the help of a 'perfect storm', we find ourself with the second lowest ice levels on record........and after such a high level of ice to start with eh?

Maybe those who still hold onto the 'operating within normal variance' view of Arctic ice will now start to wonder whether the 'death spiral' scenario is actually unfolding before there eyes.

All the time we watch the extent drop away we are also watching the perennial bleed away. Those who now accept the fragility of young ice during a normal melt must also wonder about the next 'cyclical warm summer' in the arctic (as many of the experts are) and how this will impact ice extents.

[Methuselah]

So, we're (whether we like it or not) pretty much on course for the second-lowest summer ice-extent since records began. And, it concerns me!

We are (according to some) 11 years' past the peak in global temperatures, and 8 years' past the Solar maximum. But (whether AGW is real or not) still the Arctic ice is retreating. Why? Why should it be still retreating? Well it could be (as Fred on How used to say, all those years ago) 'Our old friend inertia,' only in this case, of the thermal variety.

We have (should all the above assumptions be valid) now entered a new episode of climatic variation: we have, IMO, moved from a long period of rapid temperature-rise with little ice-melt, to one of static temperaure but with rapid ice-melt? And, to me, this is suggestive of thermal inertia of some kind...

On the other hand, it could be a short-term transient -ive feedback relating to the latent heat required to melt the ice?

Who knows?

[Gray-Wolf]

The worry for me Pete are the positive feedbacks that the open water itself poses (when areas previously ice bound are no longer so).

If it (the new 'dark water') is enough to cause an extended period of heat shedding before the water is able to re-freeze in Autumn, taking the form of the new Arctic Amplification, then maybe it (the extent of the recent summer melt) is enough to over-ride some of the old -ve feedbacks that used to stabilise things when the melt was excessive?

Of course we would have to accept that the amount of 'new' open water that we see today is not just part of a regular 'natural cycle' and that it is ,as the science/evidence suggests, something that is novel to our epoch.

I'm quite 'Lovelockian' in the way I try and visualise change on the planet.The normal 'balance' is kept by the many +ve and -ve feedbacks that help trim climate. If the pressure is too great in any one direction then I feel climate undergoes a 'step change' to it's new higher/lower operating parameters.

I fear that the job arctic sea ice played on moderating our climate environment is something that, if lost, could hasten us to such a 'step change'.

[Methuselah]

Yes Ian, I think you're right: once the ice has gone, it's moderating powers necessarily will have gone with it; climate will settle at a new 'equilibrium'. But, whether the causes are entirely natural or, as I firmly believe, augmented by mankind, we will have to adapt. And, in this respect, I don't see how 'navel gazing' helps. Which is where I agree with Hansen et al.

However, I do wish the anti-carbon lobby would switch its emphasis towards sustainability rather than demonizing carbon? I really do believe that people will be less cynical (thus more cooperative) if shown the benefits we can all gain through sustainability, rather than being told what to give up?

IMO, too much negativity plays straight into the hands of those who'll gain most from a BAU scenario?

[noggin]

http://climaterealists.com/attachments/database/Royal%20Society%20Letter.pdf

I am not being flippant, I'm not like that. Just wanted to make that clear!

Have a read of the italicised part of the letter (towards the end) in this link re the state of Arctic ice in 1817!

[Iceberg]

A bit of science for a change I believe most of it speaks for itself.

But essentially Greenland hasn't been this warm for 100,000 years.

Arctic Ice has never been as low for at least 100 years and probably a lot more.

Temps are incredibly high there.

http://dust.ess.uci.edu/smn/smn_arc_mlt_olli_200610.pdf?bcsi_scan_8BE53757955D3085=0&bcsi_scan_filename=smn_arc_mlt_olli_200610.pdf

Edited July 28, 2009 by Iceberg

[Methuselah]

It's not pleasant viewing, is it? An awful lot of perennial has disappeared since 1976!

[Solar Cycles]

A bit of science for a change I believe most of it speaks for itself.

But essentially Greenland hasn't been this warm for 100,000 years.

Arctic Ice has never been as low for at least 100 years and probably a lot more.

Temps are incredibly high there.

http://dust.ess.uci....olli_200610.pdf

Don't agree with any of that Iceberg! Greenland hasn't been as warm for 100,000 years, poppycock! There is no evidence to back that up at all, and you know that!

Don't agree with any of that Iceberg! Greenland hasn't been as warm for 100,000 years, poppycock! There is no evidence to back that up at all, and you know that!

Sorry forgot about your link to arctic ice, Can't really argue with that Iceberg, don't really have much evidence to suggest otherwise!

[jethro]

It's not pleasant viewing, is it? An awful lot of perennial has disappeared since 1976!

Pete, I think you may find these interesting.

http://climate.gi.alaska.edu/ResearchProjects/Hartmann%20and%20Wendler%202005.pdf

http://www.appinsys.com/GlobalWarming/The1976-78ClimateShift.htm

[Thundery wintry showers]

The one straw to clutch is that Arctic ice has been absent in the past, and it didn't result in global catastrophe or runaway warming. On the other hand it could easily produce a positive feedback on global warming over the short term...