The United Nations Climate Change Conference is scheduled to be held in Paris at the end of this year, that will host discussions on how to achieve their proposed target of a 2ºC cap on the rise in average global temperatures. However, a new study on sea-level rise says that this goal may not be enough to save coastal cities from drowning.

The study, conducted by Climate Central, says that the projected rise in sea levels caused by even a mere 2ºC increase will flood land areas currently populated by over 600 million people. The study also projects that roughly double the expected damage will occur if the global average temperature rises to 4ºC. 25 million people in the United States currently live in cities that are projected to be the subject of major flooding in that scenario, including Miami and New Orleans.

Asia is projected to be the hardest-hit region of the globe, with 75 percent of the affected population residing there. The hardest hit individual country would be China, home to four of the ten hardest-hit megacities that are projected to experience flooding, including Shanghai, Tianjin, Hong Kong and Taizhou; these four cities are home to over 44 million people. The total population expected to be affected in China alone numbers over 145 million.

"Two degrees Celsius warming will pose a long-term, existential danger to many great coastal cities and regions," says study lead author Ben Strauss, vice president for Climate Central’s Sea Level and Climate Impacts division.

Strauss also commented on the upcoming Paris climate summit, being held by the Conference of the Parties: "Some historic meetings draw national boundaries. This one will affect the global line between land and sea."