How far into the past can ice-core records go? Scientists have now identified regions in Antarctica they say could store information about Earth’s climate and greenhouse gases extending as far back as 1.5 million years, almost twice as old as the oldest ice core drilled to date. The results are published in Climate of the Past, an open access journal of the European Geosciences Union (EGU).
Potential oldest ice study areas (Credit: Van Liefferinge and Pattyn)
By studying the past climate, scientists can understand better how temperature responds to changes in greenhouse-gas concentrations in the atmosphere. This, in turn, allows them to make better predictions about how climate will change in the future.
“Ice cores contain little air bubbles and, thus, represent the only direct archive of the composition of the past atmosphere,” says Hubertus Fischer, an experimental climate physics professor at the University of Bern in Switzerland and lead author of the study. A 3.2-km-long ice core drilled almost a decade ago at Dome Concordia (Dome C) in Antarctica revealed 800,000 years of climate history, showing that greenhouse gases and temperature have mostly moved in lockstep. Now, an international team of scientists wants to know what happened before that.
At the root of their quest is a climate transition that marine-sediment studies reveal happened some 1.2 million years to 900,000 years ago. “The Mid Pleistocene Transition is a most important and enigmatic time interval in the more recent climate history of our planet,” says Fischer. The Earth’s climate naturally varies between times of warming and periods of extreme cooling (ice ages) over thousands of years. Before the transition, the period of variation was about 41 thousand years while afterwards it became 100 thousand years. “The reason for this change is not known.”
Climate scientists suspect greenhouse gases played a role in forcing this transition, but they need to drill into the ice to confirm their suspicions. “The information on greenhouse-gas concentrations at that time can only be gained from an Antarctic ice core covering the last 1.5 million years. Such an ice core does not exist yet, but ice of that age should be in principle hidden in the Antarctic ice sheet.”
As snow falls and settles on the surface of an ice sheet, it is compacted by the weight of new snow falling on top of it and is transformed into solid glacier ice over thousands of years. The weight of the upper layers of the ice sheet causes the deep ice to spread, causing the annual ice layers to become thinner and thinner with depth. This produces very old ice at depths close to the bedrock.
However, drilling deeper to collect a longer ice core does not necessarily mean finding a core that extends further into the past. “If the ice thickness is too high the old ice at the bottom is getting so warm by geothermal heating that it is melted away,” Fischer explains. “This is what happens at Dome C and limits its age to 800,000 years.”
To complicate matters further, horizontal movements of the ice above the bedrock can disturb the bottommost ice, causing its annual layers to mix up.
“To constrain the possible locations where such 1.5 million-year old – and in terms of its layering undisturbed – ice could be found in Antarctica, we compiled the available data on climate and ice conditions in the Antarctic and used a simple ice and heat flow model to locate larger areas where such old ice may exist,” explains co-author Eric Wolff of the British Antarctic Survey, now at the University of Cambridge.
The team concluded that 1.5 million-year old ice should still exist at the bottom of East Antarctica in regions close to the major Domes, the highest points on the ice sheet, and near the South Pole, as described in the new Climate of the Past study. These results confirm those of another study, also recently published in Climate of the Past.
Crucially, they also found that an ice core extending that far into the past should be between 2.4 and 3-km long, shorter than the 800,000-year-old core drilled in the previous expedition.
The next step is to survey the identified drill sites to measure the ice thickness and temperature at the bottom of the ice sheet before selecting a final drill location.
“A deep drilling project in Antarctica could commence within the next 3–5 years,” Fischer states. “This time would also be needed to plan the drilling logistically and create the funding for such an exciting large-scale international research project, which would cost around 50 million euros.”
More information
This research is presented in the paper ‘Where to find 1.5 million yr old ice for the IPICS “Oldest Ice” ice core’ published in the EGU open access journal Climate of the Past on 05 November 2013. Please mention the publication if reporting on this story and, if reporting online, include a link to the paper or to the journal website.
Full citation: Fischer, H. et al.: Where to find 1.5 million yr old ice for the IPICS ‘Oldest-Ice’ ice core, Clim. Past, 9, 2489-2505, doi:10.5194/cp-9-2489-2013, 2013.
The other study mentioned in the release is by Van Liefferinge, B. and Pattyn, F.: Using ice-flow models to evaluate potential sites of million year-old ice in Antarctica, Clim. Past., 9, 2335–2345, 2013.
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“By studying the past climate, scientists can understand better how temperature responds to changes in greenhouse-gas concentrations in the atmosphere. This, in turn, allows them to make better predictions about how climate will change in the future.”
This is about as far as I am going to read because it has been discussed over many threads and proven that increases in greenhouse-gas follow increases in temperature
Does the ice core store an information about water vapor? Really?
This obsession with “greenhouse gases” is not normal. When 6,000 ppm of greenhouse CO2 in Martian atmosphere creates any kind of “greenhouse warming”, then come back.
And the warming effect of CO2 was as strongly logarithmic 1.5million years ago as it is today so finding out how much CO2 there was in the atmosphere is a further waste of time and money.
‘Climate scientists suspect greenhouse gases played a role in forcing this transition, but they need to drill into the ice to confirm their suspicions. ‘
Any one want to bet what the result will be regardless of the facts ?
Still lets hope that unlike the usual approach the probably handle and make public all the data and not take the ‘its mine you can’t have it ‘ one some in this area use.
By studying the past climate, scientists can understand better how temperature responds to changes in greenhouse-gas concentrations in the atmosphere.
They’re starting with an agenda and will learn nothing. Still, that’s hardly the point, is it?
What RESnape said. Temperature leads CO2 not vice versa.
Whatever happened to older ice?
I wonder if they can use the directional drilling practices perfected by the fracking industry to “follow” the ice flows and get consistent data.
So much time, trouble and money wasted trying to understand “how temperature responds to changes in greenhouse-gas concentrations in the atmosphere”; so little spent trying to understand how greenhouse-gas concentrations in the atmosphere respond to changes in temperature.
By studying the past climate, scientists can understand better how temperature responds to changes in greenhouse-gas concentrations in the atmosphere. This, in turn, allows them to make better predictions about how climate will change in the future.
Holy crap. Talk about putting the cart before the horse. At least they stated their agenda up front. I stopped reading at that point.
By studying the past climate, scientists can understand better how temperature responds to changes in greenhouse-gas concentrations in the atmosphere. This, in turn, allows them to make better predictions about how climate will change in the future.
Oh really?
“…Showing that greenhouse gases and temperature have mostly moved in lockstep.”
There was me thinking that the ice cores showed that temperature increase preceded the rise in CO2 by about 800 years. Maybe lockstep applies to parts of the flat temperature periods of the ice record?
There, fixed it for them.
EDIT: Beaten to it…
New data is interesting.
Only complain when it is thrown out for not fitting the narrative.
Ice that old is probably past the expiration date, but it sounds like a worthy project. What’s the drilling cost compared to a wind turbine?
Too many scientists have a horse in this race. That statement in itself is an apparent travesty and a contradiction in terms but we live in interesting times. I’m finding it hard to remain credulous. Am I alone in thinking that whatever the outcome the published results/data will reflect a carefully scripted and entirely subjective edict?.
Congrats on finding old ice. Can I have some for my whisky?
Otherwise as per RESnape – I cannot read this after they stated their intentions mixing cause and effect.
As Bob Carter said, we can study whether lung cancer causes smoking, but that would be a waste of time and money.
“Lockstep” seems to be an intentionally misleading characterization, especially when they preface their CO2-temperature-lockstep claim by saying that a longer record of this kind of data will help scientists to better:
The relevance of “lockstep” to that objective disappears if they acknowledge that it is known to come from temperature driving CO2, with any relationship in the other direction being obscured to the point of indetectability by the temperature-drives-CO2 relation.
Science, in the public arena, is commonly used as a source of authority with which to bludgeon political opponents and propagandize uninformed citizens. This is what has been done with both the reports of the IPCC and the NAS. It is a reprehensible practice that corrodes our ability to make rational decisions.
– Richard Lindzen WSJ 2001 http://eaps.mit.edu/faculty/lindzen/OpEds/LindzenWSJ.pdf
And all our yesterdays have lighted fools
The way to dusty death. Out, out, brief candle!
Life’s but a walking shadow, a poor player
That struts and frets his hour upon the stage
And then is heard no more. It is a tale
Told by an idiot, full of sound and fury
Signifying nothing.
– William Shakespeare, circa 1605
I’m sorry, I’m not aware of the evidence that ‘greenhouse gasses’ caused the transition 900,000 years ago.
Is this controversial or do all reputable scientists (by which I include the NIPCC group as well as some IPCC scientists) agree it to be so?
Don’t these scientists have any dignity. In effect all that’s being said is the same old trite argument:
“…we got a problem, it’s CO2 but we need more money to find out if CO2 does, and by how much (cause we know it does and by loads), control climate…”
Once we stop funding this shit the sooner science can resume and academics can regain their dignity.
News Flash!!!
O Fukushima!
David Suzuki issues ominous warning for damaged Fukushima plant
http://ca.news.yahoo.com/blogs/daily-buzz/david-suzuki-issues-ominous-warning-damaged-fukushima-plant-195522191.html
If David Suzuki says it is a crisis, you can probably rest assured that it is not.
Suzuki (aka the Fruit Fly) has grown wealthy and has an enormous carbon footprint, a product of false enviro-alarmism.
I don’t get it. Why do they need real data? Don’t we have models we can use for making a hindcast? I also have to confess that as a Lovecraft fan, perhaps they should leave Antarctic ice that old… undisturbed.
But seriously, the idea of getting ice that old is just amazing. Getting ground truth going that far back could be revolutionary, and one hopes their analysis is unbiased.
“…time would also be needed to plan the drilling logistically and create the funding …. which would cost around 50 million euros”
Give me some of that rich gravy baby!!! 🙂
If you actually read the paper You find what they actually say:
Very old ice may exist at depth in a few areas in East Antarctica
The old ice will be very compressed
Empirical data suggests that oxygen isotope record may be so degraded by diffusion that even the 41 000 year glacial cycles may blurred, i. e. probably no reliable temperature data and very difficult dating.
They are convinced (from modeling) that this will NOT affect CO2.
A number of other dating methods MIGHT be useful.
Predicting where very old ice may occur is very difficult – test drilling will be required.
Strangely they do not seem to be at all interested in searching for very old ice close to the surface in blue-ice areas where it very probably exists. Admittedly such ice would not be exactly datable (unless one was lucky enough to find volcanic ash layers in it), but it would give just as good qualitative data on the “41 kyr world” (I e the period before 800 000 years ago when glacial cycles were short), as would a deep bore, better as a matter of fact as larger amounts of ice would be accessible.
“Climate scientists suspect greenhouse gases played a role in forcing this transition”
That is probably just a bid for more cash. There are a number of different theories what caused the transition from short to long glacial periods, but GHG does not figure in any of them.