US East Coast sea level 'rising faster'

2012-06-26 12:57

AP

Washington - Sea levels from Cape Hatteras to Cape Cod are rising at a faster pace than anywhere on Earth, making coastal cities and wetlands in this densely-populated US corridor possibly more vulnerable to flooding and damage, researchers at the US Geological Survey (USGS) reported.

Climate change is causing higher sea levels around the world, as land-based glaciers like those on Greenland melt and slide into the oceans and as warming ocean water expands.

But seas don't rise at the same rate, and for 966km along the US Atlantic coast, the water is rising more rapidly than elsewhere on the globe, USGS scientists reported on Sunday in the journal Nature Climate Change.

In this "hot spot" of rising sea levels, variations in ocean currents and sea water temperature and salinity push oceans upward along the coastline, the scientists said.

It could have an impact on some of the biggest urban areas along and near the East Coast, including Boston, Providence, New York City, Philadelphia, Baltimore and Norfolk-Virginia Beach, especially when storm surges push water inland.

Researchers found that sea levels in this corridor were rising between three and four times faster than the global average, and they fit with computer simulations aimed at predicting the effects of climate change.

Long-term data

One reason for the accelerated rise in the Atlantic Ocean along the East Coast is an apparent slowdown in the Atlantic Meridional Overturning Circulation, a massive current sometimes called the "conveyor belt", study author Asbury Sallenger Jnr said by telephone from St Petersburg, Florida.

The melting of glaciers, which are made of compacted snow, sends fresh water into the salty Atlantic and into this current, Sallenger said.

"It turns out that this leads to a slowdown across the whole system ... including the currents that run along the coast of the United States," he said. "And there are ways by slowing down those currents, you change the level of the sea against the coastline."

Using long-term data from tidal gauges along the cost, the researchers determined that is occurring.

The USGS's study followed another report issued on Friday by the National Research Council that indicated that much of California could see sea levels rise to above levels projected for the world as a whole by 2100.

That earlier study focused on how much the seas might rise; the USGS's report examined how fast the seas were rising on the East Coast.

The discovery of the "hot spot" could help coastal cities plan for rising seas and predict the submergence of saltwater marshes, which provide habitat for commercial fisheries and buffer the effect of storms.

- Reuters