September 29, 2009

Hemispheric climate changes found linked

U.S. geoscientists say they've found evidence that northern hemisphere climate swings during the past 12,000 years are linked to changes in the tropics.

University of New Hampshire and Columbia University scientists said their finding suggests a prolonged cold spell caused European and North American glaciers to creep forward several hundred years ago, possibly affecting climate patterns as far south as Peru and causing tropical glaciers to also expand.

Glaciers in both the tropics and North Atlantic region reached their most recent maximum extents during the so-called Little Ice Age, about 1650 to 1850, the scientists said.

The results bring us one step closer to understanding global-scale patterns of glacier activity and climate during the Little Ice Age, said University of New Hampshire Associate Professor Joe Licciardi, lead author of the study.

By understanding how glaciers behaved in the past, the geoscientists hope to predict how parts of the world will react as the planet warms.

The Intergovernmental Panel on Climate Change predicts global temperatures may climb another 1.1 degrees to 6.4 degrees Celsius by the end of this century.

If the current dramatic warming projections are correct, we have to face the possibility that the glaciers may soon disappear, said Columbia University Associate Professor Joerg Schaefer, a co-author of the research.

The study that included graduate student Jean Taggart appears in the journal Science.