Sea levels are rising much faster along the U.S. east coast than they are around the globe, putting some of the world’s most prized coastal properties in danger of flooding, government researchers report.
U.S. Geological Survey (USGS) scientists call the 965-kilometre swath a “hot spot” for climbing sea levels caused by global warming.
Along the region, the Atlantic Ocean is rising at an annual rate three to four times faster than the global average since 1990, according to the study published Sunday in the journal Nature Climate Change.
It’s not just a faster rate, but at a faster pace, like a car on a highway “jamming on the accelerator,” said the study’s lead author, Asbury Sallenger Jr., an oceanographer at the agency. He looked at sea levels starting in 1950 and noticed a change beginning in 1990.
Since then, sea levels have gone up globally about 5 centimetres. But in Norfolk, Va., where officials are scrambling to fight more frequent flooding, the sea level has jumped a total of 12.19 centimetres, the research showed. For Philadelphia, levels went up 9.4 centimetres, and in New York City, it was 7.11 centimetres.
Climate change pushes up sea levels because it causes ice sheets in Greenland and west Antarctica to melt and because warmer water expands.
Computer models long have projected higher levels along parts of the U.S. east coast because of changes in ocean currents from global warming, but this is the first study to show that’s already happened.
Margaret Davidson, director of the Coastal Services Center for the National Oceanic and Atmospheric Administration in Charleston, S.C., said the implications of the new research are “huge when you think about it. Somewhere between Maryland and Massachusetts, you’ve got some bodaciously expensive property at risk.”
Sea level projections matter in coastal states, because flood maps based on those predictions can result in restrictions on property development and affect flood insurance rates.