南极地区晚第四纪环境及其与全球变化的关系

LATE QUATERNARY ENVIRONMENT CHANGES IN ANTARCTICA AND THEIR CORRELATIONS WITH GLOBAL CHANGE

南极无冰区和冰芯的记录均表明,晚更新世以来南极地区的环境和气候变化是与全球变化一致的。在最近几十年,大气CO_2含量增加已引起南极地区气温升高,冰盖前缘缓慢消退。温室效应将促使南极冰盖(首先是陆缘冰)部分融化,但不可能崩溃。在今后50年内,南极冰盖部分消融引起的海面上升幅度将不超过2m。

Two ingressions were occurred in last glacial interstadial (50 000—25 000 a B. P.) and Holocene optimum (7 500—5 000 a B. P.) periods in Antarctic region. The great expansion of Antarctic Ice Sheet was appeared at last glacial maximum (18 000 a B. P.) when Antarctic sea level was 100—150 m lower than that at present. Three times of glacial advances and retreats occurred on the front of Antarctic ice sheet since 3 000 aB. P. All these phenomena were coordinated with global changes. In the past decades of years, records from Antarctic ice free areas and ice cores testified that environmental and climatic changes in Antarctic region were coordinated with global changes since late Pleistocene. In the past decades of years, Antarctic inland was a little warming up and the front of the ice sheet was slowly melt and retreated due to the increases of CO_2 content in the atmosphere. The green house effect will cause that Antarctic ice sheet (especially on the ice shelves) to be partly melt away, but can not destroy it. In this case the amplitude of sea level rising caused by the melting of Antarctic ice will be less than 2 m within the coming 5 decades.