Damages caused by flooding could cost cities an annual $1 trillion worldwide if mitigation efforts are not taken, according to the article, “Future Flood Losses in Major Coastal Cities,” in Nature: Climate Change.

New Orleans, Boston, New York City, and two Florida cities (Miami and Tampa-St. Petersburg) were among the 20 cities most at risk for economic loss due to coastal flooding. While developing-country cities in general are more vulnerable to coastal flooding, these U.S. cities are in comparison wealthy with limited coastal flood protection — increasing the potential for greater economic loss.

The study assessed potential damages in 136 of the world’s largest coastal cities based on increasing flood exposure due to climate change combined with increasing population, the city’s assets, and for some, subsidence. Wind damage was not assessed. This research is part of an ongoing project sponsored by the Organization for Economic Cooperation and Development.