'Hotspot' Causing Sea Level Rise Acceleration In Eastern US
June 25, 2012

‘Hotspot’ Causing Sea Level Rise Acceleration In Eastern US

The sea level of the eastern coast of the United States is accelerating at a much faster rate than the country's other coasts due to global warming, claim researchers from the U.S. Geological Survey (USGS).

According to Damian Carrington, a reporter with the UK newspaper The Guardian, the sea level rise of the "densely populated" Atlantic coast from Cape Hatteras, North Carolina to Boston, Massachusetts is increasing at a rate three to four times faster than the rest of the country's coastal regions.

Likewise, the Associated Press (AP) said, the 600-mile area, which the USGS researchers dub a "hot spot" because of the sea levels, have been rising at a rate up to 400% faster than the global average.

Among the fastest-rising areas are Norfolk, Virginia, where the sea level has increased approximately five inches since 1990, and Philadelphia, which has seen a four-inch rise.

"Many people mistakenly think that the rate of sea level rise is the same everywhere as glaciers and ice caps melt, increasing the volume of ocean water, but other effects can be as large or larger than the so-called 'eustatic' rise," USGS Director Marcia McNutt said in a statement. "As demonstrated in this study, regional oceanographic contributions must be taken into account in planning for what happens to coastal property."

"Cities in the hotspot, like Norfolk, New York, and Boston already experience damaging floods during relatively low intensity storms," added Dr. Asbury Sallenger, a USGS oceanographer and the head of the study, which is the subject of a paper published in the journal Nature Climate Change. "Ongoing accelerated sea level rise in the hotspot will make coastal cities and surrounding areas increasingly vulnerable to flooding by adding to the height that storm surge and breaking waves reach on the coast."

While Sallenger told Carrington that this hotspot affect had previously been predicted through computer modeling, the USGS study is the first to use real data to prove that the sea-level acceleration is currently occurring and that scientists can currently detect and monitor it.

The cause, he said, is the warming of dense Arctic water, causing it to sink more slowly and leveling out the so-called "slope" from the fastest-moving water in the mid-Atlantic to the east coast of America. As a result, the sea level in that location increases, and could ultimately add as much as 30% to the global sea level rise.

"We came up with a very clear correlation between the acceleration of sea level rise and rising temperature in the hotspot area. That suggests to me that as long as temperature continues to rise the hotspot will continue to grow," Sallenger told the Guardian on Sunday.