Science Source

Important role for ocean warming and increased ice-shelf melt in Antarctic sea-ice expansion

States changes in sea ice significantly modulate climate change because of its high reflective and strong insulating nature
States that in contrast to Arctic sea ice, sea ice surrounding Antarctica has expanded, with record extent in 2010
States this ice expansion has previously been attributed to dynamical atmospheric changes that induce atmospheric cooling
Shows that accelerated basal melting of Antarctic ice shelves is likely to have contributed significantly to sea-ice expansion
Presents observations indicating that melt water from Antarctica’s ice shelves accumulates in a cool and fresh surface layer that shields the surface ocean from the warmer deeper waters that are melting the ice shelves
Finds that cool and fresh surface water from ice-shelf melt indeed leads to expanding sea ice in austral autumn and winter
Finds this powerful negative feedback counteracts Southern Hemispheric atmospheric warming
States that although changes in atmospheric dynamics most likely govern regional sea-ice trends, the analysis indicates that the overall sea-ice trend is dominated by increased ice-shelf melt
Suggests that cool sea surface temperatures around Antarctica could offset projected snowfall increases in Antarctica, with implications for estimates of future sea-level rise