Ecologists use oceanographic data to predict future climate change

[amyrose2712]

From: Ecological Society of America
Published November 7, 2008 08:18 AM

Earth scientists are attempting to predict the future impacts of climate change
by reconstructing the past behavior of Arctic climate and ocean circulation. In a November special issue of the journal Ecology, a group of scientists report that if current patterns of change in the Arctic and North Atlantic Oceans continue, alterations of ocean circulation could occur on a global scale, with potentially dramatic implications for the world's climate and biosphere.

Charles Greene of Cornell University and his colleagues reconstructed the patterns of climate change in the Arctic from the Paleocene epoch to the present. Over these 65 million years, the Earth has undergone several major warming and cooling episodes, which were largely mitigated by the expansion and contraction of sea ice in the Arctic.

"When the Arctic cools and ice sheets and sea ice expand, the increased ice cover increases albedo, or reflectance of the sun's rays by the ice," says Greene, the lead author on the paper. "When more of the sun is reflected rather than absorbed, this leads to global cooling."

Likewise, when ice sheets and sea ice contract and expose the darker-colored land or ocean underneath, heat is absorbed, accelerating climate warming. Currently, the Earth is in the midst of an interglacial period, characterized by retracted ice sheets and warmer temperatures.

In the past three decades, changes in Arctic climate and ice cover have led to several reorganizations of northern ocean circulation patterns. Since 1989, a species of plankton native to the Pacific Ocean has been colonizing the North Atlantic Ocean, a feat that hasn't occurred in more than 800 thousand years. These plankton were carried across the Arctic Ocean by Pacific waters that made their way to the North Atlantic.

http://www.enn.com/sci-tech/article/38594