Increased flooding may cost the world $1 trillion by 2050

Flood damage in the world’s major coastal cities may top $1 trillion a year by 2050 due to rising seas and subsiding land, according to a new study.

The startling figure is “not a forecast or a prediction,” but rather a means to “show that not to adapt and not to improve protection is impossible,” Stéphane Hallegatte, a senior economist with the World Bank in Washington, D.C., and the study’s lead author, told NBC News. “We have to do something.”