Old ice gives new clues to climate change

Carbon dioxide levels are much higher than at any time during the past 650,000 years, scientists discover.

By , Staff writer of The Christian Science Monitor


• Today's atmosphere holds concentrations of carbon dioxide significantly higher than at any time in the last 650,000 years.


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For ice-core scientist Edward Brook, the results are likely to generate the next icon for long-term climate change. The most telling result, he adds, is the relationship between long-term CO2 trends and long-term temperature trends.

Dr. Brook, with Oregon State University in Corvallis, explains that in these latest results, the warm periods between glacial deep freezes are cooler than those over the past 440,000 years.



The new data come from the European Project for Ice Coring in Antarctica, which drilled into the ice at a spot called Dome C in eastern Antarctica. The ice at that point is 3,309 meters thick. The research team pulled a series of ice cores reaching to a depth of 3,190 meters (1.98 miles).

Measuring CO2 and other gases is relatively straightforward. Determining temperatures is more round-about. In the absence of thermometers, scientists have found that shifts in the relative abundance of two forms of hydrogen provide a useful stand-in.







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