1. Ups and downs of Greenland's ice sheet
Studies have indicated that the Greenland ice sheet is thinning, likely because of increasing average summer air temperatures in southern coastal regions. To investigate the total loss of the ice sheet's mass from 1958 through 2008, Rignot et al. study two parameters: ice discharge, which is obtained from remote sensing techniques; and surface mass balance, which is derived from a model of melting ice and snowpack accumulation. The authors find that surface mass balance and temporal variability in ice discharge are correlated for the time period studied. Using this correlation, they determine that the ice sheet lost mass during the warm period before 1970, although in the 1970s and 1980s the ice sheet accumulated almost as much mass as it had lost. However, ice sheet loss increased through the 1990s. In the past 11 years, the total mass deficit has tripled; as of 2007, about 267 billion tons of ice is lost each year. The authors also find that rather than melting, variations in ice discharge were the dominant factor in determining total ice loss.
Title:Mass balance of the Greenland ice sheet from 1958 to 2007
Authors: E. Rignot: Department of Earth System Science, University of California, Irvine, California, U.S.A.; also at Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, U.S.A.; J. E. Box: Byrd Polar Research Center, Ohio State University, Columbus, Ohio, U.S.A.; E. Burgess: Department of Geography, University of Utah, Salt Lake City, Utah, U.S.A.; E. Hanna: Department of Geography, University of Sheffield, Sheffield, U.K.
Source: Geophysical Research Letters (GRL) paper 10.1029/2008GL035417, 2008; http://dx.doi.org/10.1029/2008GL035417
2. Shrinking Arctic ice boosts phytoplankton growth
Loss of Arctic sea ice has accelerated recently, culmina
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