Tuesday, September 11, 2012

New paper finds Antarctic Peninsula has accumulated significant extra ice since 1850

A paper published today in Geophysical Research Letters finds the Antarctic Peninsula has experienced a "significant accumulation" of "up to 45 meters of extra ice thickness over the past 155 years." This finding is contrary to the alarmist claims of the highly-flawed study published by RealClimate's Dr. Eric Steig, which alleged that the Antarctic Peninsula is rapidly warming. The finding is particularly surprising since the "significant accumulation" of ice has occurred since the end of the Little Ice Age in ~ 1850. 

Key Points
  • Accumulation increase results in up to 45 m extra ice thickness over 155 years
  • Model predicts GIA-related subsidence of up to 7 mm/yr which will affect GPS
  • GRACE-derived rates of ice-mass change are biased low by ignoring this signal
Grace A. Alexandra Nield
Pippa L. L Whitehouse
Matt A. A King
Peter J. J Clarke
Michael J. J Bentley
Antarctic Peninsula (AP) ice core records indicate significant accumulation increase since 1855, and any resultant ice mass increase has the potential to contribute substantially to present-day Glacial Isostatic Adjustment (GIA). We derive empirical orthogonal functions from climate model output to infer typical spatial patterns of accumulation over the AP and, by combining with ice core records, estimate annual accumulation for the period 1855-2010. In response to this accumulation history, high resolution ice-sheet modeling predicts ice thickness increases of up to 45 m, with the greatest thickening in the northern and western AP. Whilst this thickening is predicted to affect GRACE estimates by no more than 6.2 Gt/yr, it may contribute up to -7 mm/yr to the present-day GIA uplift rate, depending on the chosen Earth model, with a strong east-west gradient across the AP. Its consideration is therefore critical to the interpretation of observed GPS velocities in the AP.

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