COLUMBUS, Ohio -- An analysis of ice cores drilled from a glacier atop a Bolivian volcano is painting a vivid picture of climate conditions in the tropics over the past 25,000 years. The ice at the bottom of the cores was formed during the last glacial maximum -- the coldest part of the last ice age -- making it the oldest core recovered from the tropics.
In a paper in the journal Science, the research team describes a climate in the tropics that was different from what many researchers have thought. The findings are the latest result from a 20-year effort to build a global climate record that reaches from the North to the South Pole.
Lonnie Thompson, professor of geological sciences and research scientist with the Byrd Polar Research Center at Ohio State University, said that the new cores are the best evidence yet that the tropics were much cooler during the last glacial stage.
Until very recently, most researchers believed that only the polar and mid-latitude regions experienced drastic cooling during that period and that the tropics were largely unaffected.
The new cores also showed that the in the region was eight times less dusty during the height of that last ice age than it is now. A decrease in dust indicates that the regional climate was the much wetter at the time, he said.