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
Being an American, the value 50.000 corresponds to fifty, not fifty thousand. When I first read this post, I thought the scientists(?) had the time the Greenland ice would finish melting accurate to 0.001 years–roughly a third of a day or 8 hours. Like the PGA advertisement–these guys are good. However, real scientists would have had the end of the melt accurate to a few seconds. /sarc
When climate scientists admit they were wrong: when they admit that they couldn’t predict the climate, that they vastly over stated the likely effects and most importantly it was wrong to mix science with eco-politics.
When they have the honesty to admit they were wrong where it is bleeding obvious they were wrong, then we might just, …. just … believe them about the future, where we won’t know if they are wrong until like exaggerated global warming, it was all too obvious for anyone except a blind idiot.
But will they admit they were wrong? No!
So, why on earth should anyone pay any heed at all to their non-science?
Ah, yes, Serreze & his “death spiral”, Wadhams & his “In the end, it will just melt away quite suddenly.” It’s odd how there came to be ice up there at all, when it simply can’t form if there’s no ice up there already. Perhaps the Earth was created with ice-caps already in place. Isn’t that what they’re implying?
“Today, already 0.8 degrees global warming has been observed.”
Uh? The globe has warmed 0.8 degrees in a DAY. Hmmm. Yup, we’re [SNIP: language. C’min, we’re a family blog here. Think of the children! -REP] . It’s all over.
“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”
CAGW’s climate sensitivity is now 8 C? What happened to IPCC’s 3.0 ~4.5 C?
Why stop at 8.0 C? Why not input 18 C into this new “novel” computer model and really be cooking.
I see a Nobel Prize in the making here…..
You gotta love what passes for *sigh*ence these days…
According to this
http://www.real-science.com/tying-1974-arctic-fraud
we might as well throw out all the crap from ALL the ice extent sites including NSDC, even our friends DMI and NORSEX ice extent, CT of course. Even with their trick to hide the previous decline from 1974 onwards, they will be getting very very desperate now as NH ice has returned to normal levels even with their tricks. Watch out for adjustments to increase the melt, be very very wary…..You see a normal NH ice will really really hurt the whole AGW theme meme LOL
““using a novel computer simulation””
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!
“Novel” as in fiction.
If this interpretation of the Vostock ice-core is correct…..
http://en.wikipedia.org/wiki/File:Vostok_Petit_data.svg
…a 2C rise in temperature would appear to be the trigger which sends the Earth plunging headlong into its next glaciation.
dccowboy says (March 12, 2012 at 9:00 am)
“We write 50 000 years. The comma is redundant.”
Isn’t the space redundant as well?
———
In the UK we still use commas.
What should be made redundant: the nuts in the Potsdam Institute for Climate Impact Research (PIK) and the Universidad Complutense de Madrid.
Credit where credit is due, glass is half full etc. The article did manage to avoid describing the simulation as “state of the art”.
dmacleo its snow but look at the ice it appears much thicker now (but less extent than 1979). The AGW had been arguing that its gotten thinner thinner more junk…If you take a look at NORSEX ice extent you will see that currently NH ice extent is completely NORMAL. based on their own baseline which is an attempt to make sure all recent years look like melting more and more but refer to this
http://www.real-science.com/tying-1974-arctic-fraud for the real story
““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.” ”
Makes one wonder how it formed in the first place.
They also seem to think that heat has a residue that will prevent future growth ???????
Now they are just making s**t up wholesale, mysteriously suggesting that our (sniff) ice sheets will never form again, under any conditions. (yanking of hair)
I love the reference to tipping points, of which they know nothing. More “we do not really know anything, but what if” non-science, bogey,man in the closet fear-mongering.
Shameless. It’s amazing what scientists will write when they know a positive peer review is guaranteed in advance.
I hope to have the mortgage on the Hilton Head beach house paid off in just about 50,000 years.
High school journalism washouts.
“If you are going to write an article intended to motivate people into flapping their arms and run in circles crying about the sky falling on their heads, you never, ever, use the following words: likely, could, might, or maybe.” Horace Greeley inventor of yellow journalism.
My favorite quote from the article is the following” humanity might be aiming” this little, indefinite, wishy washy statement tries to put all the blame on mankind, and yet fails miserably, owing to author’s failure to believe in his own article, or his desire to cover himself if it all goes wrong. If you really believe, you never use that terminology. You would write “humanity is aiming” replace all the “coulds” with are, etc.
Stark Dickflüssig says (March 12, 2012 at 9:11 am)
Perhaps the Earth was created with ice-caps already in place. Isn’t that what they’re implying?
————————-
As per design specs?
If the ice sheet melts, the archaeologist’s will be dancing in the streets doing digs of the buried Viking settlements. This means that being ice free is not unprecidented.
RE: The scientists achieved their insights by using a novel computer simulation of the Greenland ice sheet and the regional climate.
(Light Humor) There may be a correlation between increased CO2 and bad computer simulations.
Chapter 1
Once upon a time there was a man…………..a big man, a great man who made a scary movie. The movie was so scary that it made everybody in the world empty their bank accounts, wallets and cookie-jars and give all their money to scientists with novel computer simulations.
Chapter 2
Uhmmmm……………………………….uhmmm……………its coming……………….
At what point does a computer program get promoted from model to simulator? Doesn’t the term simulator imply more street cred than deserved?
FONT FEEDBACK
This article has all comments in faint caps. Preceeding article was normal. The one before that was faint caps. No pattern.
Reading the faint caps causes eyestrain!!
I’m using IE8. But I’ve had other computer issues, so who knows where the problem lies.
IanM
And after I posted my comment that all comments to this posting were in faint caps I skimmed up and found the text is normal! But after making a comment one is put onto a new page, so that might be the cause for the “cure”…..
IanM
In other news from PIK, earth’s atmosphere would be liquified if the planet was catapulted into an orbit beyond Jupiter…
@Stark Dickflüssig says:
“… Perhaps the Earth was created with ice-caps already in place. Isn’t that what they’re implying?”
Could be. They’ve borrowed the methodology of Creationism, might as well borrow the dogma, too.
More computer simulations which bear no resemblance to what happens in the real world based on history of past events. They really haven’t a clue and are simply pushing the CAGW propaganda agenda. Fools…
http://desmond.imageshack.us/Himg716/scaled.php?server=716&filename=kobiashietal2011b.gif&res=medium
Graph courtesy T Kobashi et al – 2011. Geophysical Research Letters 38:
“High variability of Greenland surface temperature over the past 4000 years estimated from trapped air in an ice core.”