North Pole ice: any thinning in sight?When searching for signs of global greenhouse warming, many researchers look north because computer climate models predict temperatures will rise most dramatically over the Arctic Ocean Arctic Ocean, the smallest ocean, c.5,400,000 sq mi (13,986,000 sq km), located entirely within the Arctic Circle and occupying the region around the North Pole. . In theory, the warming will manifest itself by thinning the pervasive sea ice in that region. But a comprehensive study of sea ice measurements at and near the North Pole North Pole, northern end of the earth's axis, lat. 90°N. It is distinguished from the north magnetic pole. U.S. explorer Robert E. Peary is traditionally credited as being the first to reach (1909) the North Pole. In 1926, Richard E. indicates that nature will not make it easy to pick out the fingerprint of greenhouse warming there. The study focuses on data collected during 12 voyages of U.S. nuclear submarines spanning the years 1958 through 1992. Over this period, sea ice thickness varied markedly from voyage to voyage, showing no identifiable trend of thinning or thickening thick·en·ing n. 1. The act or process of making or becoming thick. 2. Material used to thicken: stir in a thickening of flour and water. 3. A thickened part. , according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. physical geographer Alfred S. McLaren and his colleagues. A former submarine commander, McLaren now serves as publisher of SCIENCE NEWS. His team described its findings in The Polar Oceans and their Role in Shaping the Global Environment, published last month by the American Geophysical Union The American Geophysical Union (or AGU) is a nonprofit organization of geophysicists, consisting of over 50,000 members from over 140 countries. AGU's activities are focused on the organization and dissemination of scientific information in the interdisciplinary and . In the same volume, Peter Wadhams Peter Wadhams is professor of Ocean Physics, and Head of the Polar Ocean Physics Group in the Department of Applied Mathematics and Theoretical Physics, University of Cambridge. He is best known for his work on sea ice. of the University of Cambridge in England asserts that Arctic sea ice in certain regions was thinner, by a statistically significant amount, in the 1980s than in the 1970s. He concludes, however, that such changes do not necessarily represent a thinning trend, because natural fluctuations from year to year could explain the differences. "I think the question is still completely open because the data set is inadequate," Wadhams says. William D. Hibler III comments that both Wadham's and McLaren's groups reach the same general conclusion. "For all practical purposes, they're both saying the same thing -- that there probably isn't much of a trend there," says Hibler, an ocean researcher at Dartmouth College Dartmouth College, at Hanover, N.H.; coeducational; chartered 1769, opened 1770, the ninth colonial college (see Wheelock, Eleazar). Originally a men's college, Dartmouth began admitting women in 1972. in Hanover, N.H. Hibler's own work suggests that scientists should not rely on sea ice thickness as an indicator of climate change because sea ice responds more to winds than to air temperature. "It's questionable whether an increase or decrease in ice thickness has any relationship to climatic warming," he says. |
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