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Arctic ice melting rapidly, polar bears suffering - new research mongabay.com September 18, 2006 New research shows that Arctic sea ice is rapidly disappearing. Scientists say that the human-induced buildup of greenhouse gases in the atmosphere is a leading culprit behind the decline. According to a study to be published in the journal Geophysical Research Letters this month, the maximum amount of sea ice in the Arctic winter has fallen by six percent over each of the last two winters, while summer sea ice continues to retreat at an average of ten percent per decade. "This amount of Arctic sea ice reduction the past two consecutive winters has not taken place before during the 27 years satellite data has been available," said Joey Comiso, a research scientist at NASA's Goddard Space Flight Center. "In the past, sea ice reduction in winter was significantly lower per decade compared to summer sea ice retreat. What's remarkable is that we've witnessed sea ice reduction at six percent per year over just the last two winters, most likely a result of warming due to greenhouse gases."
"Recent changes in Arctic sea ice are rapid and dramatic," said Son Nghiem, a scientist at NASA's Jet Propulsion Laboratory and lead author of the study. "If the seasonal ice in the East Arctic Ocean were to be removed by summer melt, a vast ice-free area would open up. Such an ice-free area would have profound impacts on the environment, as well as on marine transportation and commerce." The continuing decline in winter ice could also be detrimental to marine animals. "The seasonal ice regions in the Arctic are among the most biologically productive regions in the world," warned Comiso. "Some of the richest fisheries are found in the region, in part because of sea ice. Sea ice provides melt-water in spring that floats because of low density. This melt-water layer is considered by biologists as the ideal layer for phytoplankton growth because it does not sink, and there is plenty of sunlight reaching it to enable photosynthesis. Plankton are at the bottom of the food web. If their concentration goes down, animals at all tropics level would be deprived of a basic source of food." For example, says a second NASA study, polar bears, which sit atop the Arctic food chain, appear to be a species that is adversely by retreating sea ice. "Polar bears live much of their lives on the sea ice, which is fundamental for their survival, at least in terms of their traditional lifestyles. For instance, it’s the sea ice surface that provides them a platform from which to hunt seals and other marine mammals for food," said Claire Parkinson, a senior scientist at NASA's Goddard Space Flight Center. A shorter spring hunting season caused by progressively earlier breakup of sea ice, reduces the chances of reproductive success for female polar bears. Ian Stirling, a research scientist with the Canadian Wildlife Service, noted that the average weight of adult female polar bears in western Hudson Bay have fallen from 650 pounds in 1980 to just 507 pounds in 2004, a 22 percent reduction. This article uses information and quotes from three NASA news releases. Recommend this article? Comments? Digg this article | Hugg this article | Contact News options News index | RSS | Add to MyYahoo! Advertisements: Organic Apparel from Patagonia | Insect-repelling clothing |
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