Whaling data suggest Antarctic ice retreat

One quarter decline in sea ice from 1950s to 1970s inferred from position of whale catches

A novel scientific analysis has suggested that Antarctic sea ice shifted southwards by 2.8 degrees of latitude from the mid-1950s to the early 1970s, declining in area by 25%. Although inferred rather than proved, the result provides the first clear evidence of changes in Antarctic sea ice cover before satellite pictures became available in 1973, since when no overall trend has been observed. Published in today's issue of the scientific journal, Nature, the research was based on an analysis of over 42,000 records of the southern-most position of whaling catches. Historically, whalers focused on areas around the edge of the Antarctic sea ice, where whales congregated to feed on krill, enabling Australian scientist Walter de la Mare to infer the position of the ice edge from the records. The cause of the southward shift is unknown and could be natural, but is consistent with theories of global warming.

Follow Up:
Nature , e-mail: . References: "Abrupt mid-twentieth-century decline in Antarctic sea ice extent from whaling records," Nature, Vol 389, pp 57-60.

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