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/
Moe, the temperature may not be a big issue really, as our predecessors managed to survive more difficult conditions (no houses, no heating, food gathering, [sarc] no candy, no tobacco, no bottled alcohol [/sarc] and other things that are today considered as necessary “needs” …).
Without our unique human ability to adapt to our environment, we wouldn’t be here today! Some people just seem to ignore this fact …
Slowly but surely mainstream newspapers and journals are beginning to realize that maybe they’ve been had by the 2 dozen “Climate Scientist’s” holding onto the AGW fraud.
The new results show that during the Eemian period 130,000 to 115,000 thousand years ago the climate in Greenland was around 8 degrees C warmer than today.
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Well some here claim that such high temperatures are not possible because clouds will rescue us. If it can get to +8C in Greenland it could easily get to +4C global average.
Looks like the “clouds will save us” theory goes in the trash can.
Sasja,
They may very well could have been as advanced as we are now only to be wiped out by something. Nothing lasts forever. Unless we build travel time machine, we will never know for sure. I for sure want to travel back in time to see why they built the great pyramid in Egypt that way. Too advanced, even by our building standard.
This study is presented as some great discovery, but there is nothing new here. P— on science by press release. This study simply confirms previous studies of Greenland ice cores which have been available for years. The Eemian is known in North America as the Sangamonian. For many decades this interstadial has been known to be warmer than the Holocene, as revealed through paleontology, palynology, sediment cores, geological studies, etc. This is when hippos were in the Thames.
Once there were climatologists who understood all of this. Today, the field of Climatology has been hijacked by a horde of theoretical physicists who are ignorant of (or ignore) past climate studies and who have proceeded to fashion a completely new, and utterly wrong, view of climate and climate processes based on CO2.
Apparently, in spite of the higher temperatures, no “tipping point” was reached in the Eemian, since Earth plunged right back into another ice age.
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.”
Environment Canada has just informed Canadians that we are living in a Canada that is 3.2 degrees C warmer than it was 65 years ago. And its still too cold for me.
One needs to study the graph carefully.
Here is a chart of the new NEEM temperature data (back to 128,500 years ago) versus the previous Greenland extended reconstruction temps (back to 123,000 years ago) and Antarctica (which goes all the way back to 800,000 years ago).
http://s8.postimage.org/5oikhqhad/New_Neem_Temps_vs_NGRIP_Antarctica.png
I still think there is an problem with how they are calibrating the dO18 isotopes in Greenland using borehole thermometry but at least now we have covered the Eemian.
I have mentioned it before but isotopes in precipitation are primarely a proxy for the absolute humidity / dew point of the source, which is not necesarily the same as the temperature. As the accumulation rate of the snow in Greenland seem deadlocked with the isotope ratios, it’s merely two different proxies for the same record: precipitation rate.
Consequently, it looks like the Eemian / Sangamonian interglacial was wetter than the current Holocene, but it’s not conclusive from isotopes alone if it was warmer too.
More here: https://dl.dropbox.com/u/22026080/non-calor-sed-umor.pdf
richardscourtney says:
January 24, 2013 at 3:43 am
Moe:
“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.
True, but it is also true that similar flaura and fauna..”
Gentlemen, not true – unless you mean by modern humans those who have tattoos of serpents, skulls and the like and with noise buds in their ears.
http://anthro.palomar.edu/homo2/mod_homo_4.htm
Whatever your definition, our ancestors definitely made it through a few ice ages.
“as we face global warming in the future, the answer to these questions is becoming very important.”
The truth is that this is so very important to the researchers in order to continue to receive more and more funding. This is the reality behind ALL the CAGW scientific scaremongering – follow the money.
LazyTeenager:
At January 24, 2013 at 3:43 am you write
Although all civilsations fall eventually, I fail to understand why your assertion would be – or could be – true. Please explain.
Richard
Gary Pearse:
re your dispute at January 24, 2013 at 6:09 am of my answer at January 24, 2013 at 3:43 am to the post from Moe at January 24, 2013 at 2:53 am.
Yes, hominids were around 150,000 years ago. I understood Moe to be talking about homo sapiens with capability to operate a modern industrial civilisation. And I saw – and see – no reason to be side-tracked from refuting Moe’s erroneous assertion by pedantry.
Richard
Moe says: January 24, 2013 at 2:53 am
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.
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Our species evolved on the savannas of Africa under a hot sun and it will thrive in a warmer world. Moe is the type that gets frightened easily and so is alarmed at the prospect of milder winters.
LazyTeenager says: January 24, 2013 at 3:51 am
The new results show that during the Eemian period 130,000 to 115,000 thousand years ago the climate in Greenland was around 8 degrees C warmer than today.
———–
Well some here claim that such high temperatures are not possible because clouds will rescue us. If it can get to +8C in Greenland it could easily get to +4C global average.
Looks like the “clouds will save us” theory goes in the trash can.
<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>
What “clouds will save us” theory, pray tell?
To Michael John Graham….Click onto the graph and expand the blue insert. You will see that temps were 8 degrees above the zero reference point. If you look closely on the larger chart, you will see that we are currently at that zero reference point also.
“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.”
So….Looks like temps were moving up since 30K years ago. It also is a redder color on the chart about 10,000 years which makes it hotter than in our current climate. It also looks like we are trending downward, not upward. But the big question is….What the hell can we do about it?
More about that 3.2 degrees C in Canada that I mentioned earlier.
http://opinion.financialpost.com/2013/01/23/terence-corcoran-extreme-media-alert/
Sitting here thinking how future generations will look at us and what we do to save them from whatever is to happen…I started to LTM (Laugh To Myself). They will probably have all kinds of very intelligent equipment and information, far beyond what we think is even possible, and will probably disregard anything that our primitive generation came up with. They will probably laugh their asses off about us. Will we be disregarded as we disregard other previous generations.
If’ you’re going to make a Mann reference, at least stick with Mann’s work. As far as I know he didn’t use Yamal, that was Briffa. Mann’s golden goose was a stand of Bristlecones in the US Southwest.
Interesting, but not new news. Prof. Uriarte’s excellent book Earth’s Climate History has an entire chapter on the Eemian. Previous ice cores showed 5C above present in Greenland. This new NEEM core, plus DYE-3, mean that substantial portions of the Greenland Ice Sheet remained intact, which does shift the focus to West Antarctic ice as many techtonicly stable areas show (e.g. Via coral reefs) that sea level peaked about 4 meters above present. Northern hemisphere pollen, diatom, and varve studies suggest intraEemian climate variability about like that experienced in the Holocene–that is, some, with at least one equivalent to the LIA that lasted about 400 years.
So, it sure looks like the past millennium and the past century are mostly normal. CAGW has a huge signal to noise problem. Almost no signal and strong natural background noise, now provably inadequately modelled as even Hansen is now forced to admit.
“Overpopulation is no real problem today, but will be the day it becomes obvious that we have entered into the next ice age.”
Realize this….The current world population if place within the borders of the US would supply each person with 7.5 acres of land or 15 acres per couple or 30 for a family of 4. Keep in mind that the rest of the earth would be human free. I don’t think that we are going to over populated anytime soon.
Well some here claim that such high temperatures are not possible because clouds will rescue us. If it can get to +8C in Greenland it could easily get to +4C global average.
Looks like the “clouds will save us” theory goes in the trash can.
#################
No, thunderstorms in the tropics are salvation. They keep the planet within a narrow band of temperatures.. opps.
or here is another logic defying statement.
well, obviously the planets temperature can vary by 8 degrees due to natural forcing, therefore C02 can have no effect. I’ve seen that nonsense more times than I care to count.
Fires have started by lightening, therefore arson cannot cause fires.
Steven Mosher:
I have read your post at January 24, 2013 at 8:25 am but I fail to make any sense of it.
Please try to rephrase it in an understandable form.
For example, what is the relevance of your comment about the ignition of fires when this thread is about analysis of a Greenland ice core and ice does not burn?
Richard
We manage to live in Antarctica, the high Asian deserts, Siberia, tropical islands, Mohave dessert…get to the moon, … so what is the point? There is a north/south temperature gradient and an elevation temperature gradient. We seem to manage just about anywhere. Necessity is the mother of what?
The little ice age killed a lot of Europeans, however; they were not blessed with today’s technology.