Greenland Ice Cores: Frozen in Time; February 1998; Scientific American Magazine; by Alley, Bender; 6 Page(s)
One of the grand challenges for modern science is to predict climate. Researchers especially wish to learn about large surprises--changes that could help one society flourish or lead another to devastation. Will Europe return to the warmer temperatures of 1,000 years ago, when the Vikings settled Greenland and Britons nurtured vineyards? Or could California suffer extended droughts, lasting centuries, just as the region endured roughly a millennium ago? Recent concerns about global warming and the effects of man-made greenhouse gases have only heightened the need to understand the basic natural processes that cause the climate to change.
To gain this fundamental knowledge, climatologists have turned to the past. Drilling deep below the surface of ice sheets and glaciers in Greenland, Antarctica and elsewhere, scientists have obtained water frozen for tens of thousands of years. Trapped in the ice are trace chemical impurities containing precious information about ancient climate.