Ancient Ice Revealing Climate Secrets

KNOXVILLE, Tenn., June 18 (UPI) — A U.S. scientist studying 800,000-year-old polar ice says ocean currents play a significant role in increasing carbon dioxide in the earth’s atmosphere.

Jerome Chappellaz told a Knoxville, Tenn., conference the roughly 40 percent increase of carbon dioxide in the atmosphere since the end of the last Ice Age is due in large part to changes in the circulation of the oceans surrounding Antarctica as glaciers receded and melted, a University of Tennessee at Knoxville release said.

By studying old snow in ice core samples, Chappellaz said, scientists can identify the source of atmospheric carbon dioxide in ancient times.

As glaciers and ice melted, Chappellaz said, carbon dioxide was released into southern oceans, where currents transport more water than anywhere else in the world.

Intense circulation of currents brought deep waters to the surface, releasing large amounts of carbon dioxide into the atmosphere, he said.

Concentrations and ratios of the primary greenhouse gases — carbon dioxide, methane and nitrous oxide — have changed since Ice Age times, and examining ancient ice cores can provide clues about climate change over large time scales, Chappellaz said.

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