Increases in the amount of snow falling on Antarctica has helped to offset rates of twentieth-century global sea-level rise, reports a study published online this week in Nature Climate Change. The findings emphasize the key role of the Antarctic Ice Sheet in governing both short- and long-term sea-level variations.
Global sea levels are rising, principally driven by warmer sea waters occupying more space, and the enhanced melting of glaciers and ice-sheets. However, sea level can be further modulated by changes in snowfall, which impacts the volume of frozen water that is ‘stored’ in glaciated regions such as Antarctica.
Brooke Medley and Elizabeth Thomas use ice-core records to reconstruct the snow accumulation across Antarctica from 1901-2000. Averaging over the entire continent, the authors find an increase in snowfall across the twentieth century; this, they propose, is connected to warming temperatures that allow the atmosphere to hold more moisture. The authors suggest that this increase in snow has offset approximately 10 mm of global sea-level rise since 1901. However, the increased ice mass gained from snowfall is roughly one third that of ocean-driven ice loss, the authors caution, suggesting that snow cannot fully mitigate current and future ice losses associated with anthropogenic climate change.