In the United States, between 20 and 31 million people are living on land that would be submerged by rising oceans without aggressive cuts to greenhouse gas emissions, according to a study published on Monday in the Proceedings of the National Academy of Sciences. That scenario could occur if global average temperatures rise by 3.3 degrees Celsius (5.9 degrees Fahrenheit) from pre-industrial levels by the end of the century, said the study's lead author, Benjamin Strauss. http://www.trust.org/item/20151012190151-c6xs9/