From the Potsdam Institute for Climate Impact Research (PIK) some “could be might be” research with a possible conclusion. I wonder why there doesn’t seem to be evidence for a complete melt long ago in this paper: New study shows temperature in Greenland significantly warmer than present several times in the last 4000 years. And I laughed out loud at this line: “In contrast, if global warming would be limited to 2 degrees Celsius, complete melting would happen on a timescale of 50.000 years.” Amazing how that 2°C lines up with with activist memes, doesn’t it? Oh, and Milankovitch cycles, natch.
The Greenland ice sheet is likely to be more vulnerable to global warming than previously thought. The temperature threshold for melting the ice sheet completely is in the range of 0.8 to 3.2 degrees Celsius global warming, with a best estimate of 1.6 degrees above pre-industrial levels, shows a new study by scientists from the Potsdam Institute for Climate Impact Research (PIK) and the Universidad Complutense de Madrid. Today, already 0.8 degrees global warming has been observed. Substantial melting of land ice could contribute to long-term sea-level rise of several meters and therefore it potentially affects the lives of many millions of people.
The time it takes before most of the ice in Greenland is lost strongly depends on the level of warming. “The more we exceed the threshold, the faster it melts,” says Alexander Robinson, lead-author of the study now published in Nature Climate Change. In a business-as-usual scenario of greenhouse-gas emissions, in the long run humanity might be aiming at 8 degrees Celsius of global warming. This would result in one fifth of the ice sheet melting within 500 years and a complete loss in 2000 years, according to the study. “This is not what one would call a rapid collapse,” says Robinson. “However, compared to what has happened in our planet’s history, it is fast. And we might already be approaching the critical threshold.”
In contrast, if global warming would be limited to 2 degrees Celsius, complete melting would happen on a timescale of 50.000 years. Still, even within this temperature range often considered a global guardrail, the Greenland ice sheet is not secure. Previous research suggested a threshold in global temperature increase for melting the Greenland ice sheet of a best estimate of 3.1 degrees, with a range of 1.9 to 5.1 degrees. The new study’s best estimate indicates about half as much.
“Our study shows that under certain conditions the melting of the Greenland ice sheet becomes irreversible. This supports the notion that the ice sheet is a tipping element in the Earth system,” says team-leader Andrey Ganopolski of PIK. “If the global temperature significantly overshoots the threshold for a long time, the ice will continue melting and not regrow – even if the climate would, after many thousand years, return to its preindustrial state.” This is related to feedbacks between the climate and the ice sheet: The ice sheet is over 3000 meters thick and thus elevated into cooler altitudes. When it melts its surface comes down to lower altitudes with higher temperatures, which accelerates the melting. Also, the ice reflects a large part of solar radiation back into space. When the area covered by ice decreases, more radiation is absorbed and this adds to regional warming.
The scientists achieved their insights by using a novel computer simulation of the Greenland ice sheet and the regional climate. This model performs calculations of these physical systems including the most important processes, for instance climate feedbacks associated with changes in snowfall and melt under global warming. The simulation proved able to correctly calculate both the observed ice-sheet of today and its evolution over previous glacial cycles, thus increasing the confidence that it can properly assess the future. All this makes the new estimate of Greenland temperature threshold more reliable than previous ones.
Article: Robinson, A., Calov, R., Ganopolski, A. (2012): Multistability and critical thresholds of the Greenland ice sheet. Nature Climate Change [doi:10.1038/NCLIMATE1449]
Weblink to the article once it is published: http://dx.doi.org/10.1038/NCLIMATE1449
For further information please contact:
PIK press office
Phone: +49 331 288 25 07
E-Mail: press@pik-potsdam.de
Assuming we don’t get another ice age during that time. 😉
(comma inserted for clarity).
So, are they (PIK) stating a steady temperature state of 2°C from pre-industrial (1800’s)? So according to the most noted temperature chart around, Mann’s Hockey Schtick Graph, we are already 0.4°C there. I don’t see in the article where they are looking for a 2°C (or 3°C per IPCC) change PER CENTURY. So are they abdicating the 2-3°C increase per century, in favor of another plateau (like the one we are currently experiencing) and a stable temp of 1.6°C from our current ‘norm’? Heck, with the expanded growing season and expanded agricultural acreage, I’ll take another 1.6°C and hold there.
pwl says:
March 12, 2012 at 8:29 am
Is that 50 years or 50,000 years? The Europeans use a decimal for a comma.
The British use a decimal point to denote decimal places. The Continental Europeans all seem to like using a comma, to denate all sorts. 50,000.00 would be 50, 000,00 on the mainland, the decimal just to 2 places as per usual. As a structural engineer we have recently upgraded, if that can be the correct term for it, to use the “Eurocodes” for structural design. The grave concern (literally) was that those of us in the UK, that is the regional satellite island state within the PDRofEU, would get rather confused adjusting to using a comma as opposed to a decimal point. So they actually relented & we silly old Brits can now carry on using a decimnal point, not a comma! I see the Euro is hanging on for grim life! Ho hum.
An interesting feedback mechanism…
Ok, I’m sold. /sarc According to that theory, once you lose the ice sheet on Greenland, it is impossible for it to grow back. The only problem with that conclusion is that Greenland at least once before, and probably many times, had forests. (Science Daily July 5, 2007.)
Could it be that the tipping point that could CREATE a 3000 meter high ice cap on Greenland is a climatic event worth worrying about?
Death by a thousand paper cuts!!
By the time all the ice melts we’d have already run out of fossil fuel 49.800 years before that anyway, apparently. (That’s 200 years from now)
Just a thought! What is the opposite of a textbook Green House Effect?
I don’t suppose they mentioned how clouds behave in their simulation, and how they know how they behave. Or maybe there aren’t any clouds around a big chunk of ice.
@More Soylent Green! says:
“At what point does a computer program get promoted from model to simulator? Doesn’t the term simulator imply more street cred than deserved?”
A “model” is a mathematical description of some entity. It may or may not have a temporal component. e.g. An atmosphere model might describe temperature and pressure as a function of altitude.
A “simulation” is built from interrelated models run over time. e.g. If you add a model of hourly insolation to the atmosphere model, you get simulation that gives you pressure and temperature at altitude as a function of sunlight.
If you want increased fidelity, you add optical properties of the atmosphere at altitude, how they change in response to insolation, humidity, water vapor transport, geographic location, etc.
Those are very simple examples, but you should get the idea.
A simulation gets (street cred” through the process called “Independent Verification and Validation” (IV&V). None of the climate “simulations” have been through this, which is why people like me consider them evidence of junk science.
Richard S Courtney says:
March 12, 2012 at 8:37 am
“This item is a poor attempt at justifying more research funding. The only polite and appropriate response is, ’Must do better’.”
Richard, I know you are a polite man, but I would prefer to just say “Thanks for your effort, but your services will no longer be needed”
I thought Ice started melting at 32º, is it now going to start melting at 30º?
Discover Channel had a program about a Save-The-Ice project that went to Greenland, at one of the dozen or so major choke points that export 85% of Greenland’s sea-ice. In March they covered ten hectares with white canvas. By September the ice under the canvas hadn’t melted and was three feet higher than the surrounding ice.
For about $100 billion we could keep all the checkpoints covered with enough canvas to halt entirely the glacial advance through them, by depriving them of lubrication by meltwater. That’s a lot cheaper than emission reductions, since it goes directly to the danger of sea-level rise. Good thing the sea level is actually going down!
Of course, there’s no accelerated mass loss and there will be no Greenland warming, but it’s nice to know that we could save Greenland if we had to.
“timescale of 50.000 years,” and according to the article, .8 of the 1.6 degree warming needed has already occured..
50,000 years makes no sense, and they should know it. In 50,000 years, the earth will be well into the next glacial period. They say the ice will melt “fast,” and we’re already 1/2 way the the 1.6 needed to melt the ice…I’d bet they really meant 50 years.
Message to self: Next time start at the bottom of article. 😉
Ken Hall says:
March 12, 2012 at 9:18 am
I wish that they would put that crap at the beginning of those articles so that we would not have to waste time reading the rest of it!
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Whenever I hear the “doom and gloom” stories about AGW, I always presume that “model” will be in there!!
thanks Stomata,
was noticing the thickness too.
as far as more snow, well it does not stick on unfrozen earth to well so I suspect (assume, maybe in error) its well frozen below it and it will solidify into ice at some point. does here (maine) often at least, suspect it acts the same up there 🙂
will check that link too, thanks.
Ian L. McQueen says:
March 12, 2012 at 9:50 am
“I’m using IE8. But I’ve had other computer issues, so who knows where the problem lies. ”
That’ll be with windoze then. Dual boot Linux Mint (uses Firefox as standard) & xfce desktop environment. My 3 yr old laptop with dual core T6500 now runs as fast as a 2nd gen i5. Enjoy!
Is there another climate conference happening? I have seen a bu***load of these silly studies hitting google news in the last week. Or is it just the fast response team pushing the BS out the door to help offset the negative press they have been getting.
I had a flash back from my school period (late 1980’s, 9th grade, final year at primary school, Sweden), where we are in a physics class calculated how much energy is required to transfer water from one state (melting, freezing …)to another (state). We calculated not larger volumes than one liter, due to complexity.
If they have performed their calculations after an improper linear calculation, I can understand their results (ie. to melt 1 m3 requires 1000 times more energy to melt than 1 liter – wrong!), But it is in reality something quite different, since the surrounding ice cools and the surrounding ice in turn cool the latter and the surrounding ice in turn cool the latter and …. With snow on top, we also need to take into account the insulating effect, correct?
And yes, Alan the Brit @ur momisugly 8:44 am, Greenland looks like a bowl beneath the ice.
dccowboy @ur momisugly 9:00 am: Usually yes, numbers are separated, however, in this way when there is an obvious risk of misreading (at least in Sweden).
dtbronzich @ur momisugly 9:38 pm, Yellow Journalism? Connection to the yellow snow? 😉
Don’t get hung up on the comma. A little thought before writing would avoid ruining the thread.
50,000 has to be 50.000 no matter which system otherwise it would be 50.000 english form.
Germans and Austrians write number almost the same way, as do Swiss and Lichtensteiner. In Germany it is DIN (Deutsche Industrie Norm), and after that Duden, who determine how. (DIN also defines the size of paper that practically everybody uses).
In Switzerland the “Bundeskanzlei” is the model, and the have to set French, Italien and Romantsch standards, too.
Swiss may write 50 000 or 50’000 and normally use the comma (except in banking).
In algebra the little cross for multiplication can be mixed up with the variable x, so a point is used instead..
Bob Diaz, it was some time ago that I came across the correlation between piracy and global warming http://www.seanbonner.com/blog/archives/001857.php.
Given the recent upturn in piracy in the Indian Ocean, is it any surprise that the planet is now cooling?
Ms X will take 2,8 years to finish her studies, and in this time she needs 12 sets of pill per year, which cost 9,00 $ each. By multiplying 2,8 by 12 and by 9 she gets 3’000 $ total:
2,8 . 12 . 9,00 = 3’000
In German this is called a “Kommafehler” (comma mistake).
“…using a novel computer simulation…”
They weren’t satisfied with getting a Nobel Peace Prize for their “science”, now they’re trying for the Nobel in literature (in the fiction category).
dmacleo says:March 12, 2012 at 8:58 am
think this is on topic, can someone explain this?
If you are referring to the snow, that was added intermittently in 2004, becoming a permanent feature by 2005.
Do these people ever get off their duffs and actually DO RESEARCH? Or are they only capable of thinking up more scare tactics and punching numbers into a computer to produce “validation” of their WAG?
The scientists achieved their insights by using a novel computer simulation of the Greenland ice sheet and the regional climate. … All this makes the new estimate of Greenland temperature threshold more reliable than previous ones.
Yawn…. More computer models claiming to be more reliable than the old models. Been there, done that, declined to buy the souvenir teeshirt and baseball hat.
When will they learn that we are not impressed with “data” from models? Anyone can create a model. Over the course of my career, I have coded dozens of models. The hard and expensive part is validating a model against real world empirical data. Please don’t even try to tell me that your new model was “validated” against the previous models. It’s a circular argument which carries little (i.e., no) weight with me.
BTW,
Q: Does anyone ever create a model *less* reliable than the previous ones?
A: Yes, it happens all the time! But no one ever admits to it!