About that beach house...
It was bad enough when the U.N.'s Intergovernmental Panel on Climate Change (IPCC)--the agglomeration of the world's top climate scientists--predicted in 2007 that the globe's oceans would rise by 16.5 feet if the West Antarctic ice sheet were to melt. But now comes a new study projecting that, in California and along the West Coast, the rise would be as much as 30% higher--21.5 feet.
According to a paper published Friday in the journal Science, sea levels would be affected differently in various regions of the planet if the massive ice sheet were to shrink as a result of global warming. Oceans around Antarctica would actually retract, according to researchers from Oregon State University and the University of Toronto. But in the Northern Hemisphere they would rise more than expected.
"There is widespread concern that the West Antarctic Ice Sheet...may be prone to collapse in a warming world," the researchers wrote. But author Peter U. Clark, a geosciences professor at Oregon State, cautioned, "It may not happen for hundreds of years, and even then it may not melt in its entirety."
Nonetheless he suggested, "If you are planning for sea level rise, you had better plan a little higher."
The burning of fossil fuels for industry and transportation has risen dramatically over the last century, heating up the planet, scientists say. In the U.S., California and other coastal states are developing "adaptation" plans, laying out strategies to cope with the expected effects of climate change. A recent study by UC Berkeley estimated that California has about $2.5 trillion in real estate assets--including beach property--endangered by climate change.
According to the Science journal study, the variability of the sea level rise from Antarctic ice melt would result from the gravitational force of the ice sheet, which pulls water toward it; changes in the Earth's rotation if the ice were removed; and a rebound of the ocean bottom, on which the massive glacier now rests.
The West Antarctic ice sheet looms 6000 feet above sea level over an area the size of Texas. In a warming world, what happens to Antarctica, to the Greenland ice sheet and to glaciers around the globe will influence how much oceans rise, as they have in past geologic eras. An explosion of new studies has already rendered some of the IPCC's predictions out of date: based on earlier estimates, the group had projected a growth in the East and West Antarctic ice sheets. But observations now show that Antarctic melt is already contributing to sea level rise. "Almost everyone agrees they got the ice sheets wrong," Clark said.
The National Science Foundation, which partly financed the research, posted a video of the researchers discussing their findings.
Photo: The West Antarctic ice sheet covers about one-third of the continent, on the lower left-hand side of the photo. Credit: Google Earth