Wednesday, August 20, 2014

Here’s How Arctic Sea Ice Could Shrink Even More

A map showing wave heights in the Arctic based on wave model run with conditions during a September 2012 storm. (Credit: Thomson and Rogers, 2014) Click to enlarge.
As the sea ice covering the Arctic continues to shrink under the influence of greenhouse gas-induced warming, it’s causing a host of other changes in the region, including the growth of large waves in the previously iced-over areas.  Those waves could potentially reinforce and hasten the demise of sea ice, leading to further changes in the fragile polar realm.

Changes brought on by global warming in the Arctic region have been well documented.  Temperatures there have risen twice as fast as the global average.  That rise is tied to a decline in Arctic sea ice, which has seen its seasonal minimum area shrink by nearly 14 percent per decade since the late 1970s.  Those changes could be influencing weather patterns in lower latitudes of the world, though that’s an area of continuing research for scientists.

And in the latest sign of more changes afoot, according to a recent study published in the journal Geophysical Research Letters, waves are swelling to heights never before seen in the Arctic Ocean — a shift that’s tied to the loss of sea ice and could further exacerbate it.

“With that extra expanse of space, not only are you building more waves and bigger waves but the characteristics of the waves change,” said study lead author Jim Thomson, an oceanographer at the University of Washington.

With any expanse of open water, a little breeze can stir ripples or even choppy waves. You can see it on display at your local pond or even by blowing across the surface of a glass of water.

But large expanses of open water give waves time to really get rolling and form swells. Waves that roll in at the beach are the product of a complex interaction of weather and ocean patterns hundreds, or sometimes even thousands, of miles away.

Thomson recently analyzed data from 2012, the year with the lowest summer sea ice minimum recorded, and found swells of unprecedented heights in the Arctic.  The results show that during two major storms in the region, waves swelled up to 16 feet in height.

The swells in the Arctic could expedite the recession of sea ice and coastal erosion, both already problems for the region.

Here’s How Arctic Sea Ice Could Shrink Even More

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