Wednesday, May 21, 2014

Biggest Loser: Thawing Greenland Competes with Collapsing Antarctic for Fastest Ice Loss

U.S. east coastline flooded 20 meters (69 feet) (Credit: / Alex Tingle) Click to enlarge.
Several new studies underscore scientists’ concerns we’re headed toward a coastline flooded at least 20 meters (66 feet) over many hundreds of years, as shown on the left.

The worst-case scenario for sea level rise has now become simply the “business-as-usual” scenario, recent studies from NASA make clear.  NASA glaciologist Eric Rignot, co-author of a new Greenland study, says that, taken together, the new papers “suggest that the globe’s ice sheets will contribute far more to sea level rise than current projections show.”

That means if we don’t reverse carbon pollution emissions trends ASAP, sea level rise will likely be 4 to 5 feet or more by century’s end.  Also, the rate of sea level rise in 2100 could be upwards of 1 inch per year!

No one has any concept of how to adapt cities, ports, infrastructure and the like to such a rate of sea level rise.  This underscores the New York Times reporting last week that we are risking “enough sea-level rise that many of the world’s coastal cities would eventually have to be abandoned.”

Last week two studies provided evidence that the West Antarctic Ice Sheet has begun an irreversible process of collapse, in part because its key glaciers are grounded below sea level and are melting from underneath.

Now, a team of researchers from NASA and UC Irvine reports that the Greenland ice sheet has a similar instability:
Greenland’s icy reaches are far more vulnerable to warm ocean waters from climate change than had been thought, according to new research by UC Irvine and NASA glaciologists.  The work, published Sunday in Nature Geoscience, shows previously uncharted deep valleys stretching for dozens of miles under the Greenland Ice Sheet.

The bedrock canyons sit well below sea level, meaning that as subtropical Atlantic waters hit the fronts of hundreds of glaciers, those edges will erode much further than had been assumed and release far greater amounts of water.
Biggest Loser: Thawing Greenland Competes with Collapsing Antarctic for Fastest Ice Loss

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