Arctic Sea Ice Is Getting Thinner, Faster

While a few minutes ago, an NPR reporter asked someone studying the psychology of climate denialism if environmentalists were partly to blame by over-alarmist warnings. With most people knowing that global warming is a real problem, NPR has to be more subtle about how they serve their fossil fuel corporate donors. The fact is that climate scientists have been conservative in their predictions, not wanting to turn out to be alarmist. The result is that change has happened faster than predicted.

http://www.climatecentral.org/news/arctic-sea-ice-getting-thinner-faster-18726

By Andrea Thompson
Mar. 4, 2015

While the steady disappearance of sea ice in the Arctic has been one of the hallmark effects of global warming, research shows it is not only covering less of the planet, but it’s also getting significantly thinner. That makes it more susceptible to melting, potentially altering local ecosystems, shipping routes and ocean and atmospheric patterns.

New data compiled from a range of sources — from Navy submarines to satellites — suggests that thinning is happening much faster than models have estimated, according to a study aiming to link those disparate data sources for the first time. University of Washington researchers Ron Lindsay and Axel Schweiger calculated that in the central part of the Arctic Ocean basin, sea ice has thinned by 65 percent since 1975. During September, when the ice reaches its annual minimum, ice thickness is down by a stunning 85 percent.

While the ice’s extent is readily visible from satellites, ice thickness has been more difficult to measure, and it is arguably the more important dimension in measuring the volume of ice being lost. In estimating ice thickness, satellites must try to gauge thickness differences of just a few feet from hundreds of miles above the planet’s surface. “It’s a tricky business,” Lindsay said.

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What they found was that annual average sea ice thickness over the entire Arctic basin was decreasing about 18 inches per decade since 2000.

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he study’s estimates of the sea ice thinning, detailed in the journal The Cryosphere, were more dramatic than what most models currently show, but overall, Lindsay said, the models are capturing the decline in thickness fairly well.

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