From: David A Gabel, ENN
Published February 18, 2011 09:08 AM

How Rising Sea Levels Will Affect the US Coastline

Thankfully, no major US city has gone underwater due to rising sea levels caused from global climate change. What happened in New Orleans was an effect of Hurricane Katrina, a failure of the levees, and the fact that part of the city was built below the water level. However, climate experts predict that sea levels will rise as ocean temperatures increase and the polar ice caps melt. Contingency plans are already being formulated by vulnerable US coastal cities. According to a new study led by scientists at the University of Arizona (UA), rising sea levels could cover up to nine percent of the land area in 180 US cities by 2100.


The parts of the country that will be hit hardest are the southern Atlantic coast and the Gulf coast. Cities like Miami, New Orleans, Tampa, and Virginia Beach could lose over 10 percent of their land area by the turn of the century. Scientific projections call for sea levels to rise by one meter by then, and this area is particularly flat and low-lying, much like the Netherlands.

For all the ensuing centuries, sea level will rise another meter for each century at the current rate of global warming. "According to the most recent sea-level-rise science, that's where we're heading," said lead researcher Jeremy L. Weiss, a senior research specialist in the UA's department of geosciences. "Impacts from sea-level rise could be erosion, temporary flooding and permanent inundation."

Of the 180 towns affected, twenty have populations over 300,000 people. In total, these coastal towns account for 40.5 million people. If sea level rise was to continue to a height of three meters, major northeastern cities such as Boston and New York would lose ten percent of their land area. The more vulnerable southeastern cities would lose up to 20 percent of their land.

If sea level rise was to continue up to six meters, about one third of the land area in all US coastal cities would be affected. "Our work should help people plan with more certainty and to make decisions about what level of sea-level rise, and by implication, what level of global warming, is acceptable to their communities and neighbors," said co-author Jonathan T. Overpeck, a UA professor of geosciences and of atmospheric sciences and co-director of UA's Institute of the Environment.

As part of their research, the UA team developed maps of how sea level rise could affect the entire coastline. They also developed detailed maps for individual cities or metropolitan regions. They took into account the fact that sea level rise would not just affect oceanfront properties. It would also affect inland properties that are connected to the ocean by channels, inlets, creeks, and adjacent low-lying areas. For example, Washington DC is not on the ocean, but the Potomac River is an inland extension of the ocean and would also rise.

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