Coastal snow in Antarctica

An increase in snowfall rates across Antarctica is likely to be the single largest factor slowing down sea-level rise during this century. However, there are still difficulties in predicting the magnitude of this effect. In part, this is because much of the snowfall lands in a relatively coastal strip around Antarctica. This strip is relatively narrow and is only poorly resolved by the present generation of climate models, but such is the size of the Antarctic continent that even small percentage changes in precipitation rates in this area can have a substantial impact.

To begin to understand the magnitude of the process throughout the 21st Century, ice2sea French scientists working in Grenoble have undertaken an assessment of results from many climate models. Although prediction of small percentage changes in precipitation over large areas poses substantial difficulties for all climate models, the ice2sea researchers found general agreement between the models and showed that snowfall in the coastal margin of Antarctica (generally within 250 km of the coast) contributed around 3 times more than the interior of the continent. This could account for 1 mm per year of reduction in sea-level rise by 2100. In addition, the researchers showed that a further increase in model resolution will be required in the models to simulate the impact of warming on Antarctic snowfall rates more precisely.

Publication: Genthon, C., G. Krinner, and H. Castebrunet (2009), Antarctic precipitation and climate change predictions: Horizontal resolution and margin vs plateau issues, Annals of Glaciology, 50, 55-60.

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