南極・北極に見る地球温暖化の現状と将来 : 南極・北極は本当に温暖化しているのか?

Abstract

この30 年地球全体は温暖化の兆候にあるが, 氷の世界である南極, 北極の極地もやはり温暖化しているのだろうか. 極地の氷はどうなるのだろうか. 最近の研究成果から迫ってみた.

It is apparent that we are in the global warming within the recent 30 years; however, it is not sure whether the Antarctic and Arctic cryosphere is also warming. We would like to review the direction of polar cryospher based on the recent studies. Large warming is evident in the polar regions, north west America, Siberia and Antarctic Peninsula, due to polar amplification. Recently we are confronted to the abrupt reduction of summer sea ice in the Arctic. The reduction rate is far more rapid than IPCC climate model prediction, which implies that we still do not understand the mechanism of climate change exactly. The main part of the Antarctic, East Antarctica, shows no clear warming trend in contrast to the rapid surface air temperature increase at stations in the Antarctic Peninsula/ West Antarctica. 2500m deep ice core drilling at Dome Fuji revealed the three cycles of glacial - inter glacial variation during 340 thousand years and showed a great similarity among the deep ice cores drilled in Antarctica and Greenland. Melting and retreating of ice shelves and glaciers will lead to the reduction of ice sheets and then might contribute to the sea level rise.