杏吧原创

If Antarctica鈥檚 ice melts

Antarctica is the only continent lying wholly within the grip of an ice age. If an uninterrupted accumulation at a steady pace is assumed, the ice cap must have taken between 20,000 and 33,000 years to grow to its present size and shape.

But now all weather statistics confirm a gradual warming of the atmosphere at the Earth鈥檚 surface. Will this warming lead to shrinkage of the ice mass, as at first seems logical? Or, as some geophysicists think, will warmer air carry more snow to deepen the ice layer? It is time for some serious analysis of the prospects.

The recent National Academy of Sciences Polar Research Committee report on Antarctica warns: 鈥淭here is ample evidence that the ice sheet has in the recent geological past been more extensive and on an average at least 300 metres thicker than it is at present. In view of such fluctuations, changes of considerable magnitude, including complete disappearance, may reasonably be expected to occur in the future.鈥�

The immediate ravages of unleashed water might not, however, be the worst effect of ice cap melting. The continental shelf of the South Polar land lies four times lower than normal, suggesting that if the ice (more than a mile thick below sea level at some points) were removed, the continental surface would rise. The present mountains would attain considerable heights and introduce new frictional opposition to prevailing winds, so new weather patterns would be created.

There is ample agreement among the writers of the NAS report that more must be learned, and as quickly as possible.

From New 杏吧原创, 6 April 1961