Arctic Sea Ice Is Getting Thinner, Faster

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.

The information is key in determining when parts of the Arctic may become ice-free for at least part of the year in the coming century.
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Since 1975, the annual average thickness in just the central part of the basin had dropped from about 11 feet to 4 feet  — a decline of 65 percent.  That was nearly double the 36 percent decline that a previous study calculated over the period from 1975-2000.

The 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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