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Greenland Ice Core Analysis Shows Rapid Climate Changes Near End of Last Ice Age
21 June 2008
Information gleaned from a Greenland ice core by an international science team shows that two Northern Hemisphere temperature spikes prior to the close of the last ice age some 11,500 years ago were tied to fundamental shifts in atmospheric circulation.
The ice core showed the Northern Hemisphere briefly emerged from the last ice age some 14,700 years ago with a 22-degree-Fahrenheit spike in just 50 years, then plunged back into icy conditions before abruptly warming again about 11,700 years ago. The Greenland ice core evidence showed that a massive reorganization of atmospheric circulation in the Northern Hemisphere coincided with each temperature spurt, with each reorganization taking just one or two years, said the study authors.
The new findings are expected to help scientists improve existing computer models for predicting future climate change as increasing anthropogenic greenhouse gases in the atmosphere push up Earth’s temperatures globally.
The team used changes in dust levels and stable water isotopes in the annual ice layers of the two-mile-long Greenland ice core, which was hauled from the massive ice sheet between 1998 to 2004, to chart past temperature and precipitation swings. Their paper was published in the 19 June issue of Science Express.
The ice cores were drilled as part of the North Greenland Ice Core Project led by project leader Dorthe Dahl-Jensen of the Centre for Ice and Climate at the Neils Bohr Institute of the University of Copenhagen. The study included 17 co-investigators from Europe, one from Japan and two from the United States: Jim White and Trevor Popp from the University of Colorado at Boulder.
We have analyzed the transition from the last glacial period until our present warm interglacial period, and the climate shifts are happening suddenly, as if someone had pushed a button.
—Dorthe Dahl-Jensen
According to the researchers, the first abrupt warming period beginning at 14,700 years ago lasted until about 12,900 years ago, when icy conditions returned for about 1,200 years before the onset of the second sharp warming event. The two events indicate a speed in the natural climate change process never before seen in ice cores, said White, director of CU-Boulder’s Institute for Arctic and Alpine Research.
Both dramatic warming events were preceded by decreasing Greenland dust deposition, indicating higher tropical temperatures and significantly more rain falling on the deserts of Asia at the time, said White. The team believes the ancient tropical warming caused large, rapid atmospheric changes at the equator, the intensification of the Pacific monsoon, sea-ice loss in the north Atlantic Ocean and more atmospheric heat and moisture over Greenland and much of the rest of the Northern Hemisphere.
White likened the abrupt shift in the Northern Hemisphere circulation pattern to shifts in the North American jet stream as it steers storms around the continent.
We know such events are in Earth’s future, but we don’t know when. One question is whether we can see the symptoms before big problems occur. Until we answer these questions, we are speeding blindly down a narrow road, hoping there are no curves ahead.
—Jim White
Each yearly record of ice can reveal past temperatures and precipitation levels, the content of ancient atmospheres and even evidence for the timing and magnitude of distant storms, fires and volcanic eruptions. The cores from the site—located roughly in the middle of Greenland at an elevation of about 9,850 feet—are four-inch-diameter cylinders brought to the surface in 11.5-foot lengths.
Resources
J. P. Steffensen et. al. (2008) High-Resolution Greenland Ice Core Data Show Abrupt Climate Change Happens in Few Years, Science Express DOI: 10.1126/science.1157707
June 21, 2008 in Climate Change | Permalink | Comments (17) | TrackBack (0)
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What fun we will have in the year that the Greenland ice sheet slides into the sea.
Posted by: richard schumacher | Jun 21, 2008 9:32:16 AM
Finally, it will be Green land again!
Posted by: | Jun 21, 2008 10:38:34 AM
Obviously caused by the CO2 from all the campfires of our ancestors foolish enough to live in the northern hemisphere.
Posted by: Albert G. | Jun 21, 2008 1:26:51 PM
The main points on this study are as follows:
- Changes in ocean currents change climate and can’t be reversed by man.
- The climate tripping point will take only a year or two at most to flip.
- It’s not nice to screw with mother nature
Posted by: Axil | Jun 21, 2008 9:35:10 PM
Moving further down among the 'main points'...
We need to be prepared.
In terms of understanding (science) and capability (surplus resource and productive capacity, an agreed purpose and plan).
We need to be prepared to apply our knowledge and resources to protect and preserve life on earth.
Is our consumptive lifestyle compatible with this (less spoken but more fundamental) objective.
Assuming there is a hierarchy of human needs then one optimis(z)able principle would be that :-
A resource should not be used for any purpose which is less vital than the purpose it would be used for in the future.
This isn't a 'free market' principle - but does anyone disagree with it?
Is it right for me to use gasoline/petrol now to joy ride/go on holiday if when the planet flips into the next period of glaciation - that gasoline would be used to keep someone else alive.
Is it really about Green House Gas (we hear so much fruitless agenda reinforcing here on GCC about that)?
Or is it about common sense planning for the future?
Or is it about justice, how are we going to agree to resource justice for future generations if we don't agree about justive for current generations.
Is it right for me now to use petrochemicals for leasure activities if these same resources could provide food, shelter or medicine for someone less well off.
I'm not saying I do the right thing (I don't). I'm just saying that green communications / transportation is a form of resource modesty which is justified because it increases our capacity to support life, to cope with external threats (like flipped climate states).
I'm saying I find the debate about Global Warming interesting but I thought using existing resources sparingly and developing new resources a quickly as we can (stably) was just common sense? like banking options for the future?
Anybody?
Posted by: Robert | Jun 23, 2008 5:16:44 AM
I wonder if this finding has anyting to do with the earth passing through a celestial equator that is prophisized by the ancient myan indians and was recently shown on discovery channel. kind of a coincidence i think that the earth will pass through this equator again and it only occurs once in 25 - 26 thousand years and when you look at the numbers of the last ice ages, we are getting close to that time agian?
Posted by: | Jun 23, 2008 10:09:53 AM
Just not what we needed to hear...I mean for crying out loud that's fast. (I'm mostly saying that as I think the world running tight on Oil and eventually, a decade or two thereafter, Natural Gas will trump climate change as policy focus for governments in the future).
Posted by: Sasparilla | Jun 23, 2008 11:44:50 AM
The human chimpanzee species is quite closely following the population dynamics curve of bacteria in a petri dish.
Posted by: Mark_BC | Jun 23, 2008 6:22:54 PM
""I'm saying I find the debate about Global Warming interesting but I thought using existing resources sparingly and developing new resources a quickly as we can (stably) was just common sense?""
Common sense goes by the wayside when short-term corporate profits are involved and the politicians making decisions for us are in bed with them. Throw in a little religious fundamentalism clouding our vision and you can say good-bye to common sense long-term planning. (Jesus is going to come back down and save all the true believers from the cesspool we are turning Earth into)
Posted by: Mark_BC | Jun 23, 2008 7:08:02 PM
Wait a sec', this:
"The new findings are expected to help scientists improve existing computer models for predicting future climate change as increasing anthropogenic greenhouse gases in the atmosphere push up Earth’s temperatures globally."
-
Doesn't make sense. If what you're telling me is that the Earth has undergone more dramatic change in the past *without* any "anthropogenic" anything, why do they care to craft computer models on it? As with the current cooling, which they didn't tell us was going to happen, we now learn that nature determines these things, not my car.
Posted by: Gary | Jun 24, 2008 7:01:05 AM
>>
"The new findings are expected to help scientists improve existing computer models for predicting future climate change
<<
Hardly a week passes without some urgently important new data that is "expected to help" "improve" models used for propagandizing pre-determined anti-prosperity grant-seeking activity. The new urgent news totally contradicts last week's authoritative and urgent news.
The ONLY constant (K) in this entire exercise is that K=>>socialism, max(government_control), min(liberty), optimized for (elites^bureaucrats). The only subtext is the desire to diminish the power and prosperity of the US. (if that was not true, why give a pass to India and China in any way?)
Posted by: theBuckWheat | Jun 24, 2008 8:01:01 AM
""Doesn't make sense. If what you're telling me is that the Earth has undergone more dramatic change in the past *without* any "anthropogenic" anything, why do they care to craft computer models on it?""
Not exactly. This data shows that temperature increases in the tropics transferred to the polar latitudes and caused fast dramatic changes. What this tells us is that you can change external forcings gradually to some extent and things can be stable for so long, until a tipping point is reached where a major shift happens. This is how ice ages start and stop. The Milankovitch orbital fluctuations which mostly determine ice age cycles are gradual, but the transitions into and out of ice ages are abrupt.
""As with the current cooling, which they didn't tell us was going to happen,""
There is no current cooling trend. 1998 was the warmest year on record and in comparison makes everything since seem "cooler". Take away 1998, and you still have a strong warming trend.
http://en.wikipedia.org/wiki/Image:Instrumental_Temperature_Record.png
Posted by: Mark_BC | Jun 24, 2008 9:53:18 PM
""The only subtext is the desire to diminish the power and prosperity of the US.""
The US is doing just fine at robbing itself of its own prosperity. 50% of the federal budget goes to servicing debt to fight sand people in the Middle East.
While the rest of the world is eagerly moving forward towards developing renewable and cheaper and more secure energy sources, the US seems to focus on using military might to bomb its way back into 1950's carbon technology. It then wonders why it gets left behind by the rest of the world and in these sticky situations like it is in now.
It's ironic, the rest of the world is embracing the economic principle the US was founded on, and is reaping prosperity as a result, but rather than just tightening the buckle and moving on, the Conservatives revert back to the old scapegoat of blaming the "socialists"
Posted by: Mark_BC | Jun 24, 2008 10:03:23 PM
The significance of the result is in showing how suddenly climate patterns can change. Past changes occurred entirely because of natural causes, but now humans are on the scene and contributing causes of their own. We may have very little time left to stop what we're doing; if we wait until the changes are obvious it will be too late to halt them.
Posted by: richard schumacher | Jun 25, 2008 7:48:26 AM
If it happens, there is nothing we can do. Are you doing anything to stop it?
Talk is cheap, make yourself heard and do something. At least that way you can say you tried.
Boy it could get could in the North East of US. Europe, brrrrrr.
Posted by: Paul | Jun 26, 2008 6:14:57 PM
That's it. When I spell cold wrong it is time to go to bed.
Posted by: paul | Jun 26, 2008 6:15:51 PM
"We know such events are in Earth’s future, but we don’t know when. One question is whether we can see the symptoms before big problems occur. Until we answer these questions, we are speeding blindly down a narrow road, hoping there are no curves ahead." —Jim White
I am not sure that the US is so behind....
Many NASA Scientists are both Democrat and Republican, and have made significant contributions toward finding answers to questions...
President Bush's vision of Space programs which have integrated several countries, and remain the most aggressive scientific challenge toward addressing the facts on climate change, in our earth's history.
And few recent successful technology launches: http://www.nasa.gov/missions/highlights/schedule.html
The US also led the World in turbine installations for the last three years...These are positive things.
And another clerification would be that the US Defense budget is not 50% of the federal budget, it is in of itself a seperate fund.
Posted by: acarara | Jun 27, 2008 1:34:41 AM
