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
It’s worse than we thought!
The PIK is a stain on Germany’s scientific reputation.
Is that 50 years or 50,000 years? The Europeans use a decimal for a comma.
“therefore it potentially affects the lives of many millions of people”
Lots of things affect people’s lives. Like the sun coming up every day.
50,000 years from now, we should be in the middle of the next ice age, with most humans living around the equator. Oh wait, CO2 is going to keep us all warm by the camp fires. Never mind.
The item says;
“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.””
So, we “MIGHT” be approaching the “critical threshold” that would induce a change over so long a time that few if any people would notice it.
But wait! The item also says;
“The scientists achieved their insights by using a novel computer simulation of the Greenland ice sheet and the regional climate.”
Oh! In that case “their insights” are merely their opinion which they programed into the computer.
This item is a poor attempt at justifying more research funding. The only polite and appropriate response is, ’Must do better’.
Richard
50,000
REPLY: Yeah I noticed that too. Its European – A
Ah, a “novel computer simulation”. That’s all right then, would hate for them to use an “old, disctrdited computer simulation”
“using a novel computer simulation”
Had to get all the way to the end of the article to get my guffaw !!
(I dunno . . . sometimes I just get tired of ya, honey . . . it’s – Ah – your hair spray . . . or something.)
Ever since I read this garbage this morning in the paper, I have been thinking of that line in ‘Plastic People’ by Frank Zappa. That said, the rest of the song also kind of matches my mood of annoyed boredom with the never ending torrent of intellectual diarrhea from the greenies and their alchemists: http://www.youtube.com/watch?v=AoOwQd-1Hrg
For extra fun, swap the word ‘people’ with science, and other adaptations also suggest themselves aplenty.
Yeah, right. A bunch of matrices punched itno a computer programme can prove Global Warming. When will these people learn! De ja vu. Pocket OED, 1925: “Novel, of new kind, strange, hitherto unknown, fictitious prose”. “Simulation, feign or pretend to have or show, wear the guise of or act the part, counterfeit, having the appearance of, shadowy likenes of, mere pretence, unreal thing”. Don’t shoot the messanger I didn’t choose the damned words, they did!
On another note, isn’t the Greenland icesheet actually in a trough due to its weight bearing down on the rock strata beneath, meaning you just get one hell of a big pond when it all melts? Then it will pour into the oceans as the rock gradually recovers, or will it? Water is heavier than ice! Ditto Antractica?
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.
Fiftythousand. I found a German article in Die Welt. Not a translation error.
“using a novel computer simulation”
From which work of fiction did they obtain it?
Writing 50,000 years in europe does not make sense unless you mean 50 years and even then it’s wrong. We write 50 000 years. The comma is redundant.
So I did read the whole article and feel like
I will never get those minutes of my life back. All of that just to find out it is a novel computer simulation.
Nonsense! The Greenland ice core data show that almost all of the past 10,000 years was warmer than present and the ice sheet didn’t disappear. The ice core data show periods of warming many times more intense as recent warming without melting the ice sheet. So much for computer modeling! Look at real data if you want to predict real events.
Greenland ice sheet may melt completely with 1.6 degrees global warming
What happened to the 2 C? Would it have anything to do with the fact that we have been cooling for the last decade and 2 C seems far out of reach?
I would settle for a decent prediction of tomorrow’s weather………….
“Therefore, we conclude that the current decadal mean temperature in Greenland has not exceeded the envelope of natural variability over the past 4000 years, a period that seems to include part of the Holocene Thermal Maximum. ”
Isn’t that pretty much all we need to hear?
“The scientists achieved their insights by using a novel computer simulation of the Greenland ice sheet and the regional climate.” Novel, indeed. File under fiction
Phew! Fifty…thousand! Almost had me going there…
And where do they get 8C from? Was someone playing ‘Doom’ instead of the ‘climate simulation’? (Oops, pretty much the same thing nowadays…).
Shouldn’t these computer models be called computer games? Must be fun to play around all day long, get impressive highscores, even paid for in a kind of scientific career … and being chief climate advisors to the German government. Would be funny if not that expensive and dangerous.
So, the U.N.’s Green Climate Fund proposed $100B USD per year to combat global warming – http://unfccc.int/cooperation_and_support/financial_mechanism/green_climate_fund/items/5869.php .
Multiply that value by the 50,000 years needed to melt the Greenland ice sheet, and… wow – that’s a lot of zeros ($5,000,000,000,000,000 USD) in unadjusted dollars, too!
think this is on topic, can someone explain this?
is the white ice or snow?
if snow seems the ice cover has increased, snow does not stay on water very well 🙂
http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=03&fd=06&fy=1979&sm=03&sd=06&sy=2012
@Adder V
“We write 50 000 years. The comma is redundant.”
Isn’t the space redundant as well?