Climate Change is Expanding Antarctica's Sea Ice

Global warming is expanding the extent of sea ice around the Antarctic Peninsula in winter, faster than in another place on Earth, according to a study unveiled Sunday.

Researchers at the Royal Netherlands Meteorological Institute said Antarctica's melting ice sheet has created a surface layer of fresher water that insulates nearby sea ice, encouraging the ice to expand in winter. Climate scientists have long been searching for an explanation as to why sea ice around Antarctica has been increasing, reaching a record extent in the winter of 2010, when ice on the Arctic Ocean at the other end of the planet shrank to a record low in 2012.

The Antarctic meltwater has a relatively low density, so it accumulates in the top layer of the ocean. These fresher waters are then able to re-freeze more easily during autumn and winter. According to Richard Bintanja and Geert Jan van Oldenborgh, researchers at the Royal Netherlands Meteorological Institute, ocean warming may actually be driving sea-ice expansion in the Antarctic.

Bintanja's study also said the cool melt water layer may limit the amount of water sucked from the oceans that falls as snow on Antarctica. Cold air can hold less moisture than warm.

"Cool sea surface temperatures around Antarctica could offset projected snowfall increases in Antarctica, with implications for estimates of future sea-level rise," it said.

Bintanja explained that it is "paradoxical and counter-intuitive" that global warming can cause loss in the northern hemisphere and lead to growth in the southern hemisphere. But that's exactly what they have found in their study.

"This was one of the big apparent contradictions we had which (skeptical) people were always very happy to point out," senior researcher Oldenborgh told The Australian. "Previously, people first thought it was due to the ozone hole, but the problem there is the ozone hole forms in spring and the big increase in sea ice is in autumn and winter."