Climate Science

Pine Island Losses

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Science  05 Nov 2010:
Vol. 330, Issue 6005, pp. 732
DOI: 10.1126/science.330.6005.732-c
CREDIT: JESSE ALLEN/NASA/U.S. GEOLOGICAL SURVEY

Mass loss from the Antarctic ice sheet is responsible for much of the observed rise in global sea level. No part of the Antarctic ice sheet is losing mass more quickly than the Pine Island Glacier, whose flow velocity has nearly doubled since the mid-1970s, although it has been unclear exactly how much mass it is losing and which factors are most responsible. Joughin et al. have developed a basin-scale glaciological model to examine the sensitivity of the Pine Island Glacier to various environmental forcings. They find that the factor most responsible for mass loss by the glacier is melting due to exposure of the ice shelf to warm ocean currents, which causes ice shelf thinning, retreat of the grounding line, and a resulting increase in the speed of ice stream flow to the sea. Their model indicates that mass loss there may continue throughout the 21st century at rates similar to, or even slightly greater than, that of the present. They suggest that the rise in sea level by the year 2100 due purely to mass loss by Pine Island Glacier will probably lie between 1.1 and 1.8 cm, perhaps inching up to 2.7 cm—a large increase but still substantially less than the theoretical maximum of between 11 and 39 cm.

Geophys. Res. Lett. 37, L20502 (2010).

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