“… abrupt climate change has been a systemic feature of Earth’s climate for hundreds of thousands of years…”
From Cardiff University
800,000 years of abrupt climate variability
An international team of scientists, led by Dr Stephen Barker of Cardiff University, has produced a prediction of what climate records from Greenland might look like over the last 800,000 years.
Drill cores taken from Greenland’s vast ice sheets provided the first clue that Earth’s climate is capable of very rapid transitions and have led to vigorous scientific investigation into the possible causes of abrupt climate change.
Such evidence comes from the accumulation of layers of ancient snow, which compact to form the ice-sheets we see today. Each layer of ice can reveal past temperatures and even evidence for the timing and magnitude of distant storms or volcanic eruptions. By drilling cores in the ice scientists have reconstructed an incredible record of past climates. Until now such temperature records from Greenland have covered only the last 100,000 years or so.
The team’s reconstruction is based on the much longer ice core temperature record retrieved from Antarctica and uses a mathematical formulation to extend the Greenland record beyond its current limit.
Dr Barker, Cardiff School of Earth and Ocean Sciences said: “Our approach is based on an earlier suggestion that the record of Antarctic temperature variability could be derived from the Greenland record.
“However, we turned this idea on its head to derive a much longer record for Greenland using the available records from Antarctica.”
The research published in the journal Science (8 September) demonstrates that abrupt climate change has been a systemic feature of Earth’s climate for hundreds of thousands of years and may play an active role in longer term climate variability through its influence on ice age terminations.
Dr Barker added: “It is intriguing to get an insight into what abrupt climate variability may have looked like before the Greenland records begin. We now have to wait until longer Greenland records are produced so that we can see how successful our prediction is.”
The new predictions provide an extended testing bed for the climate models that are used to predict future climate variability.
The collaborative research was funded in part by a Leverhulme Trust Philip Leverhulme Prize awarded to Dr Barker at Cardiff University. The prize recognises the achievement and potential of outstanding researchers at an early stage in their careers but who have already acquired an international reputation for their work. The Natural Environment Research Council and National Science Foundation in the United States also funded the research.
Website: www.cardiff.ac.uk
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@- Bomber_the_Cat says:
September 12, 2011 at 3:53 am
“We can see from this ice core record that our present inter-glacial, the Holocene, is no warmer than previous ones. In fact, according to the IPCC, it is not yet as warm as the Eemian, 100,000 years ago, Moreover, the IPCC’s Arctic Impact Assessment Report states that “the last interglacial was slightly warmer everywhere than at present…during the Eemian the winter sea-ice limit in Bering Strait was at least 800 km farther north than today, and that during some summers the Arctic Ocean may have been icefree.The northern treeline was more than 600 km farther north”.”
It is also clear that a lot of the Greenland and Antarctic ice-cap melted, sea levels were around 20 feet higher than the present. That was for a global temperature only a degree or two higher than the present, a level easily reached if CO2 driven AGW is accurate.
We also know from the A1 melt pulse that the collapse in ice-caps and rise in sea levels CAN be very rapid, with sea level rise increasing by about a foot/decade.
The abstract can be read here –
http://www.sciencemag.org/content/early/2011/09/06/science.1203580
We should ask the Vikings about that. They settled Greenland long ago, I’m sure they can tell us how climate has varied there.
Dave says:
September 12, 2011 at 6:28 am
It is clear that none of the previous commentators have read, let alone understood the Barker paper. Try reading it first. It is in the current issue of Science Express (AAAS). These comments lower the standard of `What`s Up`.
We’d be happy to read the actual paper. Got a link? Meanwhile, we’re stuck with CU’s description of it, and it comes off as pretty much your standard boilerplate CAGW claptrap. Are you saying their description is somehow inaccurate? If so, how?
And if Erich von Däniken is correct, the human race was genetically manipulated by extraterrestrials.
@- Nuke Nemesis says:
September 12, 2011 at 9:28 am
“And if Erich von Däniken is correct, the human race was genetically manipulated by extraterrestrials.”
The genetic evidence shows Erich von Däniken was wrong.
While the geological evidence shows the Eemian WAS slightly warmer, and sea levels were much higher….
Bruce Cobb: I agree. The Cardiff description is very poor indeed. The only proper source is the paper itself which is in the current issue of Science Express (AAAS). I am sorry I cannot provide an address for this paper. A good library with an AAAS subscription should have it – where I was able to read it; or, membership of AAAS will do. And, Katherine, there are 4 very informative diagrams. This is a very good paper about the geological history of the climate system over the last 800,000 years – the modelled history of Greenland over this time is incidental. The speleothem record from China, with others, is a good summary of what happened. To what extent it is useful for future prediction remains to be seen, but it is a major step on the road if `the past is the key to the present`, just as its reciprocal has allowed the assembly of these records. Enjoy some real science,
I believe you missed the point. The point is not whether there is geological evidence about the Eemian being warmer and sea levels being much higher.
I unintentionally left off added emphasis on if CO2 driven AGW is accurate. from your original post.
The point is, that’s a pretty big if and there is no evidence to support it, just like with von Daniken.
Bruce Cobb says:
September 12, 2011 at 8:44 am
[…]
We’d be happy to read the actual paper. Got a link?
[…]
===============================================
Get it at:
http://www.sciencemag.org/content/early/2011/09/06/science.1203580.full.pdf
Am I correctly understanding that they intend to use their north/south negative correlation to predict changes in the north for times back 800,000 years for which there are no ice cores in Greenland to check their predictions?
Fred;
Bedrock cores work, too, but are much harder to obtain and read.
>:)
Greenland’s ice cores only go back about 100,000 years before they become too deformed to read properly (after that, there is only another 30,000 years or so of actual ice cores).
The NGRIP people extended the ice cores back another 23,000 years by carefully matching isotopes with the Antarctic ice cores so all we have is 123,000 years back, about half-way into the Eemian interglacial.
It looks like this compared to Antarctica (divide by 2 for the global temperatures and there are also some comments on this graph about Richard Alley’s mathematical prowess).
http://img836.imageshack.us/img836/9484/lasticeageglant.png
So you could probably take this relationship and guessestimate what Greenland did over the 800,000 year period that Antarctic ice cores are available. Probably a big error margin however.
One large issue might be what happened at the interglacial 400,000 years ago. This was an especially long interglacial (although not as warm as other interglacials) so it was more like today’s interglacial (which is already a long one and might still last another 50,000 to 130,000 years more which would make it the longest interglacial in the last 2.5 million years – the Milankovitch Cycles are not as regular as many people believe).
In the interglacial at 400,000 years ago, the southern third of Greenland’s ice sheet melted out and small trees even grew there. This is based on the isotope record of vegetation remnants from the period from cores drilled to the bedrock. There is no vegetation remnants from other interglacials including the Eemian when Greenland’s temperatures were probably 4.0C to 6.0C higher than today. it probably just takes a long time to melt out the ice-sheets if temperatures are 2.0C to 3.0C higher than today.
I’ll be waiting to see what they come up with the other interglacials.
The long cores were drilled in valleys, not on mountain tops. Currently, there are about 3km of ice in those locations, During the emian (the last warm period), there were only about 60 meters .. in the valleys. Since most mountains are more than 60 m high, it is likely that much of Greenland was ice free. However, that is not the interesting part – most of the current ice (at those sites) was placed after the planet started to warm. In about 100,000 years, only a few hundred meters of ice accumulated. Several kilometers were added in the 10,000 (or so) years after the entire planet warmed. (Thus proving, beyond all doubt, that warm weather causes ice to form on Greenland. Or, more likely, a warm Gulf Stream produced snow.)
The nature of the basal ice (the lower 60 m) suggests that it might have been lakes, or swamps. (This ice has no layer structure. The only known way for this to happen is for it to melt.) The weird thing here is that the organic remains in this basal ice are about 400,000 years old. Thus, ice from about 125,000 years ago is found immediately on top of 400,000 year old organics.
Related link http://cires.colorado.edu/events/lectures/dahljensen/
Bill Illis says:
“There is no vegetation remnants from other interglacials”
Well, that’s partly because there is no ice dated from 400kyr to 125kyr. To me, that indicates that something very weird happened 125kyr ago. At the very least, there should be a layer of dust at that boundary. Yet, nothing has been found (or, at least, reported).
Here’s the thing Lazy, (you don’t mind me using your first name ?) extrapolated ice cores sound a lot like some other proxies (bristlecone springs to mind) that were used to bolster someone else’s paper. Now I don’t profess to great intellect but when two key proponents (Gore & Flannery ) of sea level rise buy waterfront properties then I know there is a ‘game’ on. I was greatly impressed with the work WUWT volunteers did on the surfacestations. That was empirical work which seems to be lacking in a lot of climate science and when Dessler says “over the decades or centuries relevant for long-term climate change, on the other hand, clouds can indeed cause significant warming” you’ve got to ask yourself, is it really worth reading all that guff – I’m certainly not getting a grant.
As Dayday says: (Good Bad Ugly thread)
September 7, 2011 at 12:57 pm
DirtyHarryreadmefile
I know what you are thinking , can I get this paper published in 5 days or can I get it published in 6, well to tell you the truth in all the excitement I kinda lost track myself but seeing this is about good science and could blow the head of your theory clean off, you have got to ask your self one question. Do I feel lucky? Well do you punk?
So Dave nope I enjoy the humour at WUWT it relieves the tedium of a Prime Minister shoving a barefaced lie in one’s face.
So Lazy, how about hopping off the sofa and try reading for comprehension.
Cheers JJ and as always a really big thanks to Anthony, mods and posters. And Anthony I still enjoy the PokeMobile thread.
I suggested this story in tips and notes last week, with a link to the pre-print press release on Physorg.
[Reply: Yes you did. The Tips and Notes page can get pretty full and some items can be missed and credit not recognized. a belated H/T and thank you. REP, mod]