Study: ‘ Greenland ice sheet is not as sensitive to temperature increases and to ice melting and running out to sea in warm climate periods ‘.
From the University of Copenhagen
Greenland ice cores reveal warm climate of the past
In the period between 130,000 and 115,000 years ago, Earth’s climate was warmer than today. But how much warmer was it and what did the warming do to global sea levels? – as we face global warming in the future, the answer to these questions is becoming very important. New research from the NEEM ice core drilling project in Greenland shows that the period was warmer than previously thought. The international research project is led by researchers from the Niels Bohr Institute and the very important results are published in the prestigious scientific journal, Nature.
In the last millions years the Earth’s climate has alternated between ice ages lasting about 100,000 years and interglacial periods of 10,000 to 15,000 years. The new results from the NEEM ice core drilling project in northwest Greenland, led by the Niels Bohr Institute at the University of Copenhagen show that the climate in Greenland was around 8 degrees C warmer than today during the last interglacial period, the Eemian period, 130,000 to 115,000 thousand years ago.
“Even though the warm Eemian period was a period when the oceans were four to eight meters higher than today, the ice sheet in northwest Greenland was only a few hundred meters lower than the current level, which indicates that the contribution from the Greenland ice sheet was less than half the total sea-level rise during that period,” says Dorthe Dahl-Jensen, Professor at the Niels Bohr Institute, University of Copenhagen, and leader of the NEEM-project.
Past reveals knowledge about the climate
The North Greenland Eemian Ice Drilling project or NEEM, led by the Niels Bohr Institute, is an international project with participants from 14 countries. After four years of deep drilling, the team has drilled ice cores through the more than 2.5 kilometer thick ice sheet. The ice is a stack of layer upon layer of annual snow fall which never melts away, and as the layers gradually sink, the snow is compresses into ice. This gives thousands of annual ice layers that, like tree rings, can tell us about variations in past climate from year to year.
The ice cores are examined in laboratories with a series of analyses that reveal past climate. The content of the heavy oxygen isotope O18 in the ice cores tells us about the temperature in clouds when the snow fell, and thus of the climate of the past. The air bubbles in the ice are also examined. The air bubbles are samples of the ancient atmosphere encased in the ice and they provide knowledge about the air composition of the atmosphere during past climates.
Past global warming
The researchers have obtained the first complete ice core record from the entire previous interglacial period, the Eemian, and with the detailed studies have been able to recreate the annual temperatures – almost 130,000 years back in time.
“It is a great achievement for science to collect and combine so many measurements on the ice core and reconstruct past climate history. The new findings show higher temperatures in northern Greenland during the Eemian than current climate models have estimated,” says Professor Dorthe Dahl-Jensen, Niels Bohr Institute.
Intense melting on the surface
During the warm Eemian period, there was intense surface melting that can be seen in the ice core as layers of refrozen meltwater. Meltwater from the surface had penetrated down into the underlying snow, where it once again froze into ice. Such surface melting has occurred very rarely in the last 5,000 years, but the team observed such a melting during the summer of 2012 when they were in Greenland.
“We were completely shocked by the warm surface temperatures at the NEEM camp in July 2012,” says Professor Dorthe Dahl-Jensen. “It was even raining and just like in the Eemian, the meltwater formed refrozen layers of ice under the surface. Although it was an extreme event the current warming over Greenland makes surface melting more likely and the warming that is predicted to occur over the next 50-100 years will potentially have Eemian-like climatic conditions,” she believes.
Good news and bad news
During the warm Eemian period there was increased melting at the edge of the ice sheet and the dynamic flow of the entire ice mass caused the ice sheet to lose mass and it was reduced in height. The ice mass was shrinking at a very high rate of 6 cm per year. But despite the warm temperatures, the ice sheet did not disappear and the research team estimates that the volume of the ice sheet was not reduced by more than 25 percent during the warmest 6,000 years of the Eemian.
“The good news from this study is that the Greenland ice sheet is not as sensitive to temperature increases and to ice melting and running out to sea in warm climate periods like the Eemian, as we thought” explains Dorthe Dahl-Jensen and adds that the bad news is that if Greenland’s ice did not disappear during the Eemian then Antarctica must be responsible for a significant portion of the 4-8 meter rise in sea levels that we know occurred during the Eemian.
This new knowledge about past warm climates may help to clarify what is in store for us now that we are facing a global warming.
Niels Bohr Institute: http://www.nbi.ku.dk/english/
Documentary films: http://www.nbi.ku.dk/english/sciencexplorer/earth_and_climate/
“This new knowledge about past warm climates may help to clarify what is in store for us now that we are facing a global warming.”
AND the lie continues to fill with stinky methane…. Are they just waiting for us to pull a finger?
This record by itself deconstructs the Hockey stick and all related “warmest evah” and “dramatic rate of change” BS. There was a study last year showing, that both by thermometers and by ice core, Greenland was as “warm” in 1940s as today, all related to AMO cycle.
This is ”me too” science. Every deep ice core that has ever been drilled in Greenland (Camp Century, Dye 3, GISP, GRIP, NGRIP, Renland) has contained Eemian (last interglacial) ice that has indicated temperatures higher than the present, usually on the order of 3-5 degrees.
What none of them has contained is an undisturbed section spanning the whole interglacial, probably because the icecap did melt to some extent during the Eemian which moved the ice divide and changed the flow pattern of the ice.
The NEEM core was supposed to have such an undisturbed section, but it didn’t. The lowest part of the core was badly sheared and the Eemian section was fragmented. The Eemian curve for NEEM shown in this post has been cobbled together by aligning the bits and pieces by comparing them with sections of similar age from Antarctica. So, while there is no doubt that the Eemian was appreciably warmer in Greenland, and that the icecap certainly did not disappear, this particular temperature curve is definitely shaky.
Please explain if I’m wrong, but from the graph, the best I can get is 3 degrees warmer not 8.
Obviously inconvenient for Mann’s few remaining Hockey Stick fans, who will undoubtedly argue one site is not the same as the whole world. I think there is a Yamal tree which is exempt from this argument.
I am not sure where the 8 degree number came from, it looks like more 3 to me. You might expect a few brickbats from your friend Gavin for this.
published in the prestigious scientific journal, Nature.
Since when ???
Do they mean to say we had SUV’s 150,000 years ago?
“…if Greenland’s ice did not disappear during the Eemian then Antarctica must be responsible for a significant portion of the 4-8 meter rise in sea levels that we know occurred during the Eemian.”
Maybe that explains this: The Piri Reis map shows the western coast of Africa, the eastern coast of South America, and the northern coast of Antarctica.
http://www.world-mysteries.com/sar_1.htm
Will this seriously damage the AGW fear campaign? If so, EU carbon will sinks to even new record lows.
How they write it:
How my brain sees it:
Also known as: 100 points from Gryffindor.
Meltwater from the surface had penetrated down into the underlying snow, where it once again froze into ice. Such surface melting has occurred very rarely in the last 5,000 years, but the team observed such a melting during the summer of 2012 when they were in Greenland.
So when cold water is buried under tons of ice it freezes,who knew? And there were all the experts saying that meltwater was disappearing down sink holes and running out to sea.
I just look at this story on the Nature web site and I’m confused by the graphic:
http://www.nature.com/polopoly_fs/7.8609.1358875603!/image/Greenland_graphic.jpg_gen/derivatives/fullsize/Greenland_graphic.jpg
Could someone explain to me why the error bars cover about 10C during the warmest period about 125,000 years ago but only about 1C around 116,000 years ago when the temperature dropped? How can the error range be 10 times greater just because it was warmer? It doesn’t seem plausible that the error range is so much greater just because it was 10,000 years earlier when they’re already talking about over 100,000 years.
Methinks that if they hadn’t put in that last bit, the paper wouldn’t have been published in the ever-less-prestigious Nature.
It’s all interesting up to the last bit, but then it blows it. Early on they say “The new results from the NEEM ice core drilling project in northwest Greenland, led by the Niels Bohr Institute at the University of Copenhagen show that the climate in Greenland was around 8 degrees C warmer than today during the last interglacial period, the Eemian period, 130,000 to 115,000 thousand years ago.“. That means quite simply that today’s temperatures are very far from unprecedented, that Earth survived them, etc etc. Instead, they end up feeding us the crap that somehow it can still be interpreted as a disaster – “Antarctica must be responsible for a significant portion of the 4-8 meter rise in sea levels that we know occurred during the Eemian.
This new knowledge about past warm climates may help to clarify what is in store for us now that we are facing a global warming.“.
Will no one rid us of this turbulent humbug.
This means a variation/uncertainty of aprox. 5000 years.
The last ice age ended aprox. 10,000 years ago, so …
and …
This is always true, just as Michael E. Mann’s* prophecies/warnings in the 1970s that we are approaching a new ice age. It depends solely on what part of the glacial cycle we are studying, but with the immediate future in mind, M.E. Mann’s* (previous) claim is more relevant.
Regarding “climate investments”, focus should be placed on how the next (and at worst current) generations living far north, will need to migrate south. Overpopulation is no real problem today, but will be the day it becomes obvious that we have entered into the next ice age.
An Orwellian/green/brown/any shade of red (“freely” chosen color) socialist solution?
* Michael E. Mann, not to be confused with Michael Mann, the film director. It is like comparing Alfred Neumann, the composer, with Alfred E. Neumann …
Well, that’s all right then – panic over.
About the 3-versus-8 degree difference. You are comparing the peak temperatures of the present and previous interglacials. The current temperature is several degrees below the early Holocene peak. You can see the recent decline as a thin grey line at the far right of the diagram. Remember that the whole diagram spans 130,000 years, so the last several cold centuries are barely visible.
Mike, ‘show that the climate in Greenland was around 8 degrees C warmer than today during the last interglacial period,’ Doesn’t describe the Earth’s temperature. It only talks about Greenland’s temperature.
Quite agree the Earth will survive these temperatures. After all the Earth was once a molten ball of rock at another time was completely covered in ice and it has survived and is still here. The question should be ‘can humans survive at these temperature?’
Because modern humans were not around 115,000 years ago, we cannot make any conclusion as to whether we would survive in a world where Greenland’s temperature is 8 (or three) degrees hotter than today.
Bill Jamison wrote:
” Could someone explain to me why the error bars cover about 10C during the warmest period about 125,000 years ago but only about 1C around 116,000 years ago when the temperature dropped? How can the error range be 10 times greater just because it was warmer? It doesn’t seem plausible that the error range is so much greater just because it was 10,000 years earlier when they’re already talking about over 100,000 years.”
See my post of 12:23 AM. The whole Eemian part of the curve is shaky. At least they admit that the results are uncertain.
Moe says:
“Because modern humans were not around 115,000 years ago, we cannot make any conclusion as to whether we would survive in a world where Greenland’s temperature is 8 (or three) degrees hotter than today.”
They were around, but only in the warmer parts (Africa and the Middle East). Apparently they somehow managed, since H. sapiens is still present.
As a matter of fact it was very likely the wetter and more hospitable conditions in Sahara and the Middle East during the interglacial that made it possible for modern humans to disperse out of Africa. Warmer normally also means wetter as all who are interested in palaeoclimate should know.
Somebody somewhere needs to build a “Climate Dashboard” so that a layman such as myself can map and compare data like this against other data sets, sun, ice, Co2, rainfall, hurricanes.
Even if a data set has only been measured for a short time rather than reverse calculated over 1’000s of years, it’d be useful…..
Mike Jonas says:
That means quite simply that today’s temperatures are very far from unprecedented, that Earth survived them, etc etc. Instead, they end up feeding us the crap that somehow it can still be interpreted as a disaster – “Antarctica must be responsible for a significant portion of the 4-8 meter rise in sea levels that we know occurred during the Eemian”.
Actually that is a clear improvement. A year or two ago the orthodox figure was 6-12 meters. A few years more and they will be back to the 2-4 meters that was the accepted figure before CAGW, and which is what the most tectonically stable coasts indicate. And incidentally about what the smaller Greenland icecap might amount to.
Michael John Graham on January 24, 2013 at 12:33 am
Please explain if I’m wrong, but from the graph, the best I can get is 3 degrees warmer not 8.
———
I think it’s referring to the insert and it’s scale in black on the left. 8 seems ok by my eye.
That’s very inconvenient….
Moe:
In your post at January 24, 2013 at 2:53 am you say
True, but it is also true that similar flaura and fauna existed then as now so it indicates there is no reason to suspect modern humans would not survive in a world where Greenland’s temperature is 8 (or three) degrees hotter than today.
Richard
Moe says
The question should be ‘can humans survive at these temperature?’
———
I am fairly certain that humans can survive. But modern civilization will not. Back to living in caves at worst and small subsistence settlements at best. A lot of dying to make the adjustment.
Moe,
Based on bone fossils and MtDNA tests, homo sapiens went as far about 150,000-200,000 years ago on this earth. Perhaps, so called “modern” human adapted to warming period… like losing their fur… 😉