Sunday, May 1, 2011

New Paper: Greenland ice sheet didn't melt despite temperatures much hotter in the past

A new paper from the 2011 Antarctic Science Symposium presents new ice core data from Greenland and finds that not even the southern portion of Greenland was ice-free during the Eemian period, despite temperatures much higher than the present (5°C or 9°F) lasting for 16,000 years (from 130,000 to 114,000 years ago). Meanwhile, alarmists such as Richard Alley (buddy of Michael Mann at Penn State) and James Hansen claim "The entire ice mass of Greenland will disappear from the world map if temperatures rise by as little as 2°C." Note global temperatures have recovered by a mere 0.7°C since the end of the Little Ice Age in 1850 and have been flat to declining since 1998.
Eemian Period from 130,000 to 114,000 years ago was est. to be at least 5°C hotter than the present

The role of the Greenland Ice Sheet in future sea levels - Based on palaeorecords from ice cores and present observations

A new Greenland ice core has been drilled. The first results from the NEEM ice core are presented and then combined with results from other deep ice cores from the Greenland Ice Sheet.

All of the ice cores drilled through the Greenland Ice Sheets have been analyzed, and the results show that all contain ice from the previous warm Eemian period near the base. Is it thus clear that the Greenland Ice Sheet has existed for over 120,000 years, going back to the previous warm period, when it was 5 deg C warmer over Greenland?

The difference between Eemian and Holocene stable oxygen isotope values has been combined with an ice sheet flow model constrained by the ice core results and internal radio echo sounding layers, to estimate the volume of the Greenland Ice Sheet 120,000 years ago.

The results show that South Greenland has not been ice-free during the Eemian period, and that the sea level contribution from the Greenland Ice Sheet has been 1 to 2 meters.

Primary Authors:    DAHL-JENSEN, Dorthe (Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen)

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