Tuesday, March 15, 2016

Rising seas to displace millions on coasts, demographers warn

[SF Gate] Millions of Americans living along the nation’s coasts will be forced to move inland by the end of the century as sea levels rise and storm surges become more frequent in this era of global climate change, a team of demographers foresees.
And nearly 700,000 coastal residents in the Bay Area would be forced to move from their low-lying neighborhoods under the most extreme conditions, the forecasters say.
According to their study, published Monday in the journal Nature Climate Change, America’s coastal areas, where as many as 13.1 million people will be living, could be prone to flooding by 2100. In the Bay Area, 250,000 people living in low-lying parts of San Mateo County would be forced to move, and in San Francisco some 33,000 would be affected, the researchers calculate.
The county-by-county analysis of America’s coastal states was put together by demographers at the University of Georgia who have tracked future population trends facing the predicted rise of oceans as the world grows warmer.
Their forecasts, they say, indicate that that if sea levels rise 3 feet by the end of this century, many sections of America’s coastal lands will be underwater and a total of 4.2 million people will have been forced to move toward higher ground.
And if the oceans rise by as much as 6 feet, the drowning lands will have sent 13.1 million Americans moving to higher ground, the demographers say.
Climate records show that sea levels around the world have been rising steadily since at least 1900, and NASA satellites have determined that the rate has doubled in the past 20 years.
Glaciers melting on Greenland and throughout the world, Antarctica’s vast ice sheets falling into the sea, and the ocean water itself expanding as temperatures warm are among the causes, climate scientists say.
Mathew E. Hauer, a demographer at the University of Georgia’s Carl Vinson Institute of Government, said he and his colleagues made their detailed forecasts by studying population trends in every American census block in every county of the 23 coastal states and the District of Columbia that could be affected by rising sea levels.
In the Bay Area’s nine counties, for example, Hauer’s group estimates that more than 350,000 people will be forced to move to higher elevations before a sea level rise of 3 feet drowns their homes by the end of this century. If sea level rise reaches 6 feet, the total forced to move will reach more than 680,000, the group estimates.
One of those people could well be Katharine Mach, a Stanford climate specialist and senior research associate at the Carnegie Institution for Science at Stanford, who lives in San Mateo County. Read More