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Looking Back
08/27/2002
Listen in RealAudio 
Hi, I'm Bryan Yeaton and this is The Weather Notebook's weekly segment on global
climate change. Where would you find the weather for every season over the last
100,000 years? The answer lies deep in the ice of the world's largest island, as our
series producer, Margaret Landsman reports.
Greenland, where it snows every month of the year and the ice sheet is two miles thick.
It's been a gold mine for climate researchers like Deb Meese.
DM: In Greenland were able to go to 110,000 years on a year by year basis to see what
the climate has been like in the past.
Meese and her colleagues were in Greenland from 1989 to 1992 and for every ten
meters they drilled down they collected a ten centimeter cylindrical sample of ice.
Recently, Meese, who is a research physical scientist with the Army Corp of Engineers
Cold Regions Laboratory, invited The Weather Notebook to see a sample.
DM: And this piece of ice is 63,000 years old. So, it fell during the last glacial period.
ML: Can you describe what that looks like?
DM: It's a cylinder that has essentially been cut in half and what you can actually see in
there are crystals. And what you're looking at are, you can see light and dark
layers...
Those light and dark layers represent different seasons of the year. Meese is able to
then determine what constitutes a whole year and she can do that for 110,000 years.
Meese's colleagues then look at other aspects of the cores and by year can see such
things as temperature shifts and changes in concentrations of greenhouse gasses.
Such information helps them look into the future more accurately.
DM: If we don't understand what's happened in the past there's no way we can plug
this information into the climate models to predict what's going to happen.
Margaret Landsman produces our weekly series on global climate change. The
series is supported by the New England Science Center Collaborative and the Roy A.
Hunt Foundation.
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