Earth Sciences Forum

scpg02 · Joined: 22 Jul 2007 Posts: 221 Location: Sacramento

Contact: Monte Basgall
monte.basgall@duke.edu
919-681-8057
Duke University

North Atlantic warming tied to natural variability; but global warming may be at play elsewhere

DURHAM, N.C. – A Duke University-led analysis of available records shows that while the North Atlantic Ocean’s surface waters warmed in the 50 years between 1950 and 2000, the change was not uniform. In fact, the subpolar regions cooled at the same time that subtropical and tropical waters warmed.

This striking pattern can be explained largely by the influence of a natural and cyclical wind circulation pattern called the North Atlantic Oscillation (NAO), wrote authors of a study published Thursday, Jan. 3, in Science Express, the online edition of the journal Science.

Winds that power the NAO are driven by atmospheric pressure differences between areas around Iceland and the Azores. “The winds have a tremendous impact on the underlying ocean,” said Susan Lozier, a professor of physical oceanography at Duke’s Nicholas School of the Environment and Earth Sciences who is the study’s first author.

Other studies cited in the Science Express report suggest human-caused global warming may be affecting recent ocean heating trends. But Lozier and her coauthors found their data can’t support that view for the North Atlantic. “It is premature to conclusively attribute these regional patterns of heat gain to greenhouse warming,” they wrote.

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http://www.eurekalert.org/pub_releases/2008-01/du-naw010308.php

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