Graham Lloyd — The Australian May 11, 2014
Antarctic sea ice has expanded to record levels for April, increasing by more than 110,000sq km a day last month to nine million square kilometres.
The National Snow and Ice Data Centre said the rapid expansion had continued into May and the seasonal cover was now bigger than the record “by a significant margin’’.
“This exceeds the past record for the satellite era by about 320,000sq km, which was set in April 2008,’’ the centre said.
Increased ice cover in Antarctic continues to be at odds with falling Arctic ice levels, where the summer melt has again pushed levels well below the average extent for 1981-2010. The centre said while the rate of Arctic-wide retreat was rapid through the first half of April, it had slowed.
The April Arctic minimum was 270,000sq km higher than the record April low, which occurred in 2007. The Antarctic sea ice extent anomalies were greatest in the eastern Weddell and along a long stretch of coastline south of Australia and the southeastern Indian Ocean. The centre said the increased ice extent in the Weddell Sea region appeared to be associated with a broad area of persistent easterly winds in March and April, and lower-than-average temperatures.
Changing wind patterns are increasingly cited to explain the expanding Antarctic sea ice.
Research suggests that the changes in Antarctic sea ice, both where it is increasing and where it is decreasing, are caused in part by the strengthening of the westerly winds that flow unhindered in a circle above the Southern Ocean.