Arctic climate more vulnerable than thought, maybe linked to Antarctic ice-sheet behavior

Jun 21, 2012
These are co-lead scientists Julie Brigham-Grette and Pavel Minyuk with core. The two scientists celebrated when drilling reached the bottom of lake sediments at a depth of 318m below the lake bottom. At that point, drilling began reaching into the 3.6-million-year-old impact rock. Credit: Courtesy of Tim Martin

First analyses of the longest sediment core ever collected on land in the terrestrial Arctic, published this week in Science, provide documentation that intense warm intervals, warmer than scientists thought possible, occurred there over the past 2.8 million years.

Further, these extreme correspond closely with times when parts of were ice-free and also warm, suggesting strong inter-hemispheric connectivity. "The are much more vulnerable to change than we thought before," say the project's Co-Chief scientists Martin Melles of the University of Cologne, Germany, Julie Brigham-Grette of the University of Massachusetts Amherst, USA, and Pavel Minyuk of Russia's North-East Interdisciplinary Scientific Research Institute in Magadan.

The keys to climate change lie buried beneath "Lake E" in the Russian Arctic. Credit: Pavel Minyuk

The data reported come from analyzing collected in 2009 from under ice-covered Lake El'gygytgyn in the northeast Russian Arctic. "Lake E" was formed 3.6 million years ago when a huge meteorite hit the Earth and blasted out an 11-mile (18 km) wide crater. It has been collecting layers of sediment ever since. Moreover, the luckily hit one of the few areas in the Arctic not eroded by continental glaciers, leaving the thick remarkably undisturbed and continuous. Consequently, cores from Lake E reach back in geologic time nearly 30 times farther than covering the past 110,000 years.

The sediment cores from Lake El´gygytgyn reflect the climatic and environmental history of the Arctic with great sensitivity. The physical, chemical and biological properties of the sediments match the glacial/interglacial pattern known globally for the ice ages. However, it is conspicuous that some warm phases are exceptional, marked by extraordinary high biological activity in the lake, well above the background of rather regular climate cycles.

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In order to quantify the climate differences associated with the variable interglacial intensities, four warm phases were investigated in detail: the two youngest, "normal" interglacials, since 12,000 years and about 125,000 years ago, and two of the "super" interglacials, about 400,000 and about 1.1 million years ago. According to pollen-based climate reconstructions, summer temperatures and annual precipitation during the super interglacials were about 4 to 5 degrees C warmer and about 12 inches (300 mm) wetter than during normal interglacials. The super interglacial climates suggest that it's virtually impossible for the Greenland's ice sheet to have existed in its present form at those times.

Simulations using a state-of-the-art climate model show that the high temperature and precipitation during the super interglacials cannot be explained by Earth´s orbital parameters or variations in atmospheric greenhouse gases alone, which geologists typically see driving the glacial/interglacial pattern during ice ages. This suggests additional climate feedbacks are at work. The scientists suspect the trigger for intense interglacials might be in Antarctica.

Earlier work by the international ANDRILL program discovered recurring intervals when the West Antarctic Ice Sheet melted. The current study shows that some of these events match remarkably well with the super interglacials in the Arctic.

This is the location of Lake E 100 kilometers north of the Arctic Circle in northeastern Russia. Credit: Arctic Climate Impact Assessment

The authors discuss two scenarios for future testing that could explain the associated inter-hemispheric climate coupling. First, reduced glacial ice cover and loss of ice shelves in Antarctica could have limited formation of cold bottom water masses that flow into the north Pacific and well up to the surface, resulting in warmer surface waters, higher temperatures and increased precipitation on nearby land.

Alternatively, disintegration of the West Antarctic likely led to a significant global sea level rise and allowed more warm surface water to penetrate into the Arctic Ocean through the Bering Strait.

"The exceptional climate warmings in the Arctic and the obvious interhemispheric interdependencies were not known before our studies", the Co-Chief scientists summarize. "The data are of global significance, taking strong indications for an ongoing collapse of ice shelves around the Antarctic Peninsula and margins of the West Antarctica Sheet and its potential acceleration in the near future – in this respect the past could be the key to the future".

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More information: "2.8 Million Years of Arctic Climate Change from Lake El’gygytgyn, NE Russia," by M. Melles et al., Science, 2012.

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User comments : 7

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NotParker
1.9 / 5 (9) Jun 21, 2012
It has happened in the past without SUV's is the key point.
TheGhostofOtto1923
2.3 / 5 (6) Jun 21, 2012
"Arctic climate more vulnerable than thought, maybe linked to Antarctic ice-sheet behavior"

-Or not. See this is why people doubt alarmists. Personally I am not much interested and think most of this hype is being used to generate support for vital new technologies needed for space colonization, among other things.

But it seems there is an unending flood of new info which alarmists have never considered and which has never been included in climate models.

How can they possibly think they know what is going on?
PhotonX
4 / 5 (4) Jun 21, 2012
It has happened in the past without SUV's is the key point.

Well, at least this means you aren't a Young Earther.
.
Rate of change is another key point, which that same data seems to suggest is now happening far faster than in the past.
NotParker
2.3 / 5 (6) Jun 21, 2012
I'm looking forward to the analysis showing how much warmer the MWP was than today.
Vendicar_Decarian
3 / 5 (6) Jun 22, 2012
ParkerTard's only hope remaining is that the MWP was global and vastly hotter than today.

Sadly it was largely regional and barely appears in the global climate record.

http://www.global..._Rev.png

"I'm looking forward to the analysis showing how much warmer the MWP was than today." - ParkerTard

Such hopes are often seen among the mentally diseased.
rubberman
1 / 5 (1) Jun 22, 2012
It has happened in the past without SUV's is the key point.

Well, at least this means you aren't a Young Earther.
.
Rate of change is another key point, which that same data seems to suggest is now happening far faster than in the past.


The rate of change is the variable that makes this question valid.

"How can they possibly think they know what is going on?"

It's pretty tough to make future predictions when taking events from the past and compressing them into a time frame that is an order of magnitude shorter than anything we have previously witnessed.
NotParker
5 / 5 (2) Jun 22, 2012
I'm looking forward to the analysis showing how much warmer the MWP was than today.


MWP in Japan. Fraudulently ignored by IPCC.

http://notrickszo...joyride/

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