Abstract
Rapid deterioration of the West Antarctic ice sheet has been warned, whereas the East Antarctica has been considered rather stable. The Japanese Antarctic Research Expedition, however, revealed that the ice sheet thickness is decreasing at a rate of 0.5 to 0.7m/year in the Shirase drainage. Ice core analyses indicated that the thinning started at ca. 1, 000 years B. P. at around Mizuho Station, which is located about 250km upstream from the coast in the Mizuho Plateau. It is considered that the thinning of the ice sheet should have contributed to the eustatic sea-level rise by about 0.1 m in the last 1, 500 years. A possible trigger and a mechanism of the thinning are hypothesized, and the sea-level rise caused by the deterioration of the West and the East Antarctica is discussed in relation with the cli - matic warming.
