The sedimentary record of Antarctic climate change

Circum-Antarctic marine sediments contain a record of past climate and Southern Ocean circulation that both complements and considerably extends the record in the continental ice. Variations in primary biological production, reflecting changes in sea-ice cover and sea surface temperature, in bottom current strength and the size of the grounded continental ice sheet, all contribute to changes in sediment characteristics, in a record extending back m any million years. It is possible to assess both the value of the proxy record in Antarctic sediments, and the validity of the analogue approach to understanding climate change, by focusing on the last glacial cycle and, for comparison, on earlier periods that were significantly different: the Pliocene before 3 Ma ago that could provide an analogue for global warming, and the Oligocene before there was an Antarctic Circumpolar Current.

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