Antarctic sea ice is expanding
Global warming has led to more ice in the sea around Antarctica and could help insulate the southern hemisphere from atmospheric warming.
A Dutch study says that unlike in the Arctic region, sea ice around Antarctica has expanded at a significant rate since 1985.
Published online in Nature Geoscience, the article suggests cool freshwater from melt beneath the Antarctic ice shelves has insulated offshore sea ice from the warming ocean beneath.
Richard Bintanja of the Royal Netherlands Meteorological Institute and colleagues say the Antarctic sea ice expands during southern hemisphere autumn and winter in response to this fresh, cool surface layer that freezes easily.
"Against the background of global climate warming, the expansion of Antarctic sea ice is an exceptional feature, which seems to be associated with decreasing sea surface temperatures in the Southern Ocean," they write.
"We predict that this mechanism will be a sizable contributor to the factors that regionally and seasonally offset greenhouse warming and the associated sea ice retreat."
They say the expanding sea ice may constitute a "feedback" that has the potential to oppose southern hemisphere atmospheric warming and amplify increases in global sea level.
Changes in sea ice can significantly modulate climate change because of its high reflective and strong insulating nature, the paper says.