The Weather Notebook: The Flip-Flop of Climate

The Flip-Flop of Climate
Listen in RealAudio
Email Your Comments

Dave Thurlow, Host

Ice core sampling, allows scientists to drill deep into glaciers, extract cylinders of ice, cutting them into slices, all to analyze the chemistry of the atmosphere 100 years ago, or more that 100,000 years ago. Hi, I'm Dave Thurlow for The Weather Notebook. So, what do these ice cores tell us? Here's Professor Cameron Wake from the University of New Hampshire's Climate Change Research Center.


Ice Core

CW: Probably the two most important discoveries that we have made from ice core research are, first of all, that carbon dioxide and methane over long time cycles, I'm talking hundreds of thousands of years, carbon dioxide and methane vary in sync with temperature.

And the second discovery?

CW: When climate changes, it changes very rapidly. It appears that the climate system actually falls in one of two different modes. It's sort of a mode 1 or mode 2. And all through the last interglacial period, there were actually 24 of these transitions between sort of cold glacier climate and not so cold glacier climate.

DT: And how long a period is that?

CW: The periods, they're quite variable in their length but they average about 1000-1500 years long. But when that climate changes from a cold, very windy climate to a not so cold, much less windy climate, those transitions actually happen over very short time periods and we think less than a decade.

So, ice cores reveal that in a matter of 10 years, almost a flip of a switch, climate regimes in Greenland for example, can fluctuate as much as 15 degrees Fahrenheit, changing the way many scientists are thinking about changes in the global climate. Funding for The Weather Notebook is provided by Subaru and the National Science Foundation.