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Sunday, June 2, 2013

Julie Brigham Grette presents Lake El'gygytgyn sediment core data showing Arctic far more sensitive to changes in CO2

by Peter Sinclair, Climate Denial Crock of the Week, June 2, 2013

Big implications here for DarkSnowproject research.

Skeptical Science:
Here is a must-see 2012 presentation by Julie Brigham-Grette of the University of Massachusetts-Amherst, covering the research her team has been doing into Lake El’gygytgyn (pronouned El-Guh-Git-Kin), a water-filled meteor crater in Arctic Russia that came into being after the impact of a ~1-km-diameter space rock, 3.6 million years ago.
This is incredibly important work because:
  • The Lake El’gygytgyn region was not glaciated during any of the ice ages. As a consequence, the more than 300-meter accumulated sequence of lake sediments represents a continuous, undisturbed sedimentary record going all the way back from the present to the aftermath of the impact.
  • The team succeeded in 2009 in extracting cores spanning this entire 3.6 million year period.
  • The oldest continuous ice core records to date extend back 123,000 years in Greenland and 800,000 years in Antarctica: the Lake El’gygytgyn cores go way back beyond those times and provide an unprecedented view of the past climate of the Arctic.
  • Results show that during the Pleistocene (2.588 million to 11.7 thousand years ago), there were a number of super-interglacials – like the present period but much wetter and several degrees warmer in the Arctic, during which the Greenland and West Antarctic ice-sheets didn’t just melt a bit. They disappeared.
Skeptical Science recently covered the new 2013 paper by the same team, describing the Arctic climate in the Lake El’gygytgyn region during the Pliocene, when boreal forests extended well up into the Arctic and summer temperatures were 8 oC warmer than they are at present:
The last time carbon dioxide concentrations were around 400 ppm: a snapshot from Arctic Siberia
The data coming from Lake El’gygytgyn strongly suggest that the Arctic climate is highly sensitive to small changes in forcing, warming much faster than the rest of the world in the phenomenon known as Arctic Amplification. In recent years, Arctic Amplification has emerged as a strong modern-day climate signal. To cite but one example, the sea-ice response has been of far greater magnitude than model-based forecasts projected. Now, the past is giving a similar narrative, and understanding the climate of the past gives us our best chance of understanding the climate of the future.
The recent publication of the research discussed above was covered at ClimateProgress, and here is the press release from UMass.

Money quotes at 17:00:  “..Greenland Ice sheet has come and gone much more frequently than
any of us had imagined.”

19:48:  “..extreme warmth many times throughout the last few million  years”  and  “..It may be much easier to get rid of sea ice than we thought before.”

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