Why The Antarctic Sea Ice Grows While The Arctic Sea Ice Melts

The Arctic sea ice is steadily melting, thinning by 65 per cent between 1975 and 2012. Yet sea ice seems to be persistently growing in Antarctica in spite of global warming. Experts supported by the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA) say that they have found out why.

Looking at temperature, topographical and bathymetric data, scientists found that local ocean depth and continental surface temperatures influence Antarctica's wind and ocean currents, sustaining the production and protection of sea ice. On the other hand, Arctic conditions lead to its ongoing melt.

"Our study provides strong evidence that the behavior of Antarctic sea ice is entirely consistent with the geophysical characteristics found in the southern polar region, which differ sharply from those present in the Arctic," said Why Son Nghiem of NASA's Jet Propulsion Laboratory and first author of the study.

With NASA's QuikScat satellite, the team could get a look at the formation and routes of Antarctic sea ice as well as different types of ice coverage in the Southern Ocean. It concluded that the winds are pushing building ice out and around the continent from June to September. This is the "sea ice growth" season. Hence, a "Great Shield" zone (GSZ) protects the ice in the interior.

On the other hand, Arctic's marginal ice zone (MIZ) is a boundary of thin, new ice easily disturbed by wind and waves. It also experiences warmer waters oftener than the GSZ. This explains its ice conditions. Still, global warming and climate change are still leading to record high global temperatures and melting glaciers, with scientists still concerned about ice loss in Antarctica.

The findings were published in the May 11 issue of the journal Remote Sensing of Environment.