The risk posed by rising seas may be even more dire than we thought.

A provocative new study suggests that as Earth’s climate continues to warm and the planet’s ice sheets continue to melt, seas could inundate coastal cities around the world, submerging vast swaths of land and displacing almost 200 million people by the end of the century.

If we continue to take a “business as usual” approach to carbon emissions, sea level rise could plausibly exceed two meters (about seven and a half feet) by 2100, the study showed. A rise of that magnitude — which is more than twice as high as the upper limit predicted in a 2013 U.N. climate assessment — would have “profound consequences for humanity,” the scientists behind the new research concluded.

New York, New Orleans, Miami, Shanghai, Mumbai and some island nations could become permanently flooded, according to that scenario, disrupting economies and displacing up to 187 million people. Almost 1.8 million square kilometers (about 700,000 square miles) of land, including some used for farming, could be permanently flooded.

Source: Rising sea levels could swamp major cities and displace almost 200 million people, scientists say