Countries most at risk from rising oceans

Between 147 to 216 million people live on land that will be below sea level or regular flood levels by the end of the century, if global greenhouse gas emissions continue at current trends, according to a new report.

The country with the largest number of people affected - between 41 and 63 million - is China, according to the report by the research group Climate Central. It ranked the United States as the 12th most at-risk country worldwide, with more than 3 million residents at risk.

This map shows the 20 countries with the largest number of people threatened by rising sea levels:

Climate Central warned that, because of potential limitations of global data it used in the analysis, this number may be two to three times too low, which means that potentially as many as 650 million people could be affected by flooding by 2100, if current emission trends continue.

"Our analysis relied on global data on elevation and population, but our experience using similar data in the U.S. strongly suggests that this global data is not as accurate or precise as more modern data sources," the report said. "If the overall error factors we calculated for the U.S. apply globally, then 300 to 650 million people live on land that will be submerged or exposed to chronic flooding, by 2100, under current emission trends," the report said.

The report also looked at the percentage of each country's population expected to be at risk. On that list, the low-lying Netherlands ranked number one, with 47 percent of its residents living in zones projected to end up under water by 2100. A quarter of the population in Vietnam, and at least one out of 10 people in Thailand and Japan, are also at risk from rising seas, according to Climate Central.