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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, F03S29, doi:10.1029/2006JF000597, 2007

Widespread acceleration of tidewater glaciers on the Antarctic Peninsula

H. D. Pritchard

British Antarctic Survey, Natural Environment Research Council, Cambridge, UK

D. G. Vaughan

British Antarctic Survey, Natural Environment Research Council, Cambridge, UK

Abstract

Over the last half century, the Antarctic Peninsula (AP) has been among the most rapidly warming regions on Earth. This has led to increased summer snowmelt, loss of ice shelves, and retreat of 87% of marine and tidewater glacier fronts. Tidewater-glacier flow is sensitive to changes in basal water supply and to thinning of the terminus, and faster flow leads directly to sea level rise. The flow rates of most AP tidewater glaciers have never been measured, however, and hence their dynamic response to the recent changes is unknown. We present repeated flow rate measurements from over 300 glaciers on the AP west coast through nine summers from 1992 to 2005. We show that the flow rate increased by ∼12% on average and that this trend is greater than the seasonal variability in flow rate. We attribute this widespread acceleration trend not to meltwater-enhanced lubrication or increased snowfall but to a dynamic response to frontal thinning. We estimate that as a result, the annual sea level contribution from this region has increased by 0.047 ± 0.011 mm between 1993 and 2003. This contribution, together with previous studies that assessed increased runoff from the area and acceleration of glaciers resulting from the removal of ice shelves, implies a combined AP contribution of 0.16 ± 0.06 mm yr⁻¹. This is comparable to the contribution from Alaskan glaciers, and combined with estimated mass loss from West Antarctica, is probably large enough to outweigh mass gains in East Antarctica and to make the total Antarctic sea level contribution positive.

Received 13 June 2006; accepted 4 January 2007; published 6 June 2007.

Keywords: flow; glacier; sea level.

Index Terms: 0758 Cryosphere: Remote sensing; 0762 Cryosphere: Mass balance (1218, 1223); 0776 Cryosphere: Glaciology (1621, 1827, 1863).

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Citation: Pritchard, H. D., and D. G. Vaughan (2007), Widespread acceleration of tidewater glaciers on the Antarctic Peninsula, J. Geophys. Res., 112, F03S29, doi:10.1029/2006JF000597.

Published in 2007 by the American Geophysical Union.