Climate History of West Antarctica Gives Clues for the Future

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Who Cares About the Ice Sheets? Why They Matter

When land ice melts, sea level rises. The loss of sea ice, although it doesn’t contribute to sea level rise in the same way (because it already displaces sea water as it floats) is significant because of its contribution to protecting the land ice. Ice shelves hold back the flow of ice streams from the Antarctic continent, and their loss will reduce this back-pressure, which may lead to increased glacier flow and consequent thinning of the ice sheet.

The ice cap on top of James Ross Island is almost 400 metres thick and contains a history of Antarctic Peninsula climate since the last ice age. Image courtesy BAS

Sea level rise is not the only outcome of melting – nor, indeed, is it necessarily the most significant.

The circulation of water around the oceans is key to heat distribution around the planet, and thus affects climate: it’s driven by temperature and density differences in the oceans.

Significant melting of ice (whether sea or land ice) introduces cold, fresh, and relatively dense water into the oceans, and may have significant impacts, as yet not quantified, upon ocean circulation.

Although the study focuses only on one area, there is separate evidence that atmospheric warming, and, in consequence, thinning of the ice sheet, is taking place elsewhere in Antarctica.

Such studies as this most recent one won’t allow us to predict the future, but they do allow scientists to increase their understanding of the complex dynamics of the Antarctic ice.

Resources

Mulvaney, R. et al. Recent Antarctic Peninsula warming relative to Holocene climate and ice shelf history. (2012). Nature. Accessed August 22, 2012.

Wilson, R. C. L., Drury, S. A. and Chapman , J. L. The Great Ice Age. (2000).  Routledge/The Open University. Accessed August 22, 2012.

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