Icy message from the Antarctic

Abstract

Satellite monitoring of the extent of sea ice in the Antarctic began only in theearly 1970s: before that there are few other data to go on. An innovative study of the records of whalers, who made many of their kills at the ice edge where whales congregated to feed, now concludes that there was a large reduction in Antarctic summertime sea-ice coverage between the 1950s and 1970s. The cause of this inferred decrease is unknown. But it is a matter of considerable interest, as the sea-ice cover of the polar oceans is an important component of the Earth's overall climate system.