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.