Rising Sea Could Sink Parts of 180 US Cities by 2100 Miami, New Orleans among most endangered By Matt Cantor, Newser User Posted Feb 17, 2011 6:09 AM CST 63 comments Comments Miami faces a threat from rising seas. (Shutterstock) (Newser) – By the end of the century, 180 coastal US cities could be partially submerged thanks to rising seas, finds a new study that looked at cities in the Lower 48 with populations of at least 50,000. The climbing sea poses a risk to, on average, 9% of the land in these cities. Those most in jeopardy? Cities that hug the Atlantic coast and Gulf of Mexico: Miami, Tampa, New Orleans, and Virginia Beach. New York City, Washington, DC, and the San Francisco Bay area could face more minor damage, Reuters reports. Threats range from erosion to a permanent influx of water, said a researcher: Miami, a relatively flat city, has "to worry about the issue in all directions," he explained, while New York, whose land rises quickly away from the coast, can focus any preventative efforts on its shoreline. The study was based on US Geological Survey data and projections of a 3-foot rise in sea levels.