NASA Announces New Record Growth Of Antarctic Sea Ice Extent

  • Date: 22/10/13
  • Spiegel Online

Researchers have measured a new record for sea-ice extent in the Antarctic. Why the white splendour is extending there while it is rapidly disappearing in the Arctic is a mystery.

 

Antarktis: Die Ausdehnung des Meereises (weiß) hat am 22. September einen Rekord erreicht. Die gelbe Linie zeigt den Median der Jahre 1981 bis 2000. Schelfeis ist grau dargestellt.

Antarctica: The extent of sea ice (white) reached a record on 22 September. The yellow line shows the median of 1981 to 2000. Ice shelf is shown in gray.

Whenever the ice at the North and South Pole is mentioned, it is mostly in the context of melting ice triggered by global warming. However, the sea ice in Antarctica – in contrast to that in the Arctic – has proved to be remarkably robust. New measurements have now confirmed that. As the U.S. space agency NASA announced, the sea ice in the Antarctic has extended over an area of ​​19.47 million square meters at the end of September. That is the highest since measurements began in 1979.

The result is based on data from the Advanced Microwave Scanning Radiometer 2 (AMSR2) on board of the Japanese satellite “GCOM-W1″. “The winter maximum has been a record for on the second consecutive year” said Walt Meier, a meteorologist at NASA’s Goddard Space Flight Center. However, he stressed that it is by no means a rapid growth: The now measured maximum extent is only 3.6 percent above the average maximum extent of 1981 to 2010. “This year, the ice edge extends therefore only 35 kilometres further out to sea than in an average year,” Meier said.

Moreover, the mere extent of sea ice does not necessarily say something about the volume of the ice, because that also depends on the thickness of the frozen layer. And the vast majority of the Antarctic ice mass is located on the Antarctic continent – and there the ice has decreased in recent years as a whole, particularly in West Antarctica.

But why the sea ice is increasing is a mystery. Scientists suspect that a change in the air currents could explain to a great extent the increase in Antarctic sea ice in recent decades. Other speculations are that ocean currents carry cooler surface water to the Antarctic or that the melting water, which flows through massive channels in the ice, decreases the temperature of the surface sea water.

Translation Philipp Mueller

Spiegel Online, 21 October 2013