WASHINGTON, DC - MARCH 13: Atmospheric physicist and Columbia University Earth Institute adjunct professor James Hansen testifies before the Senate Foreign Relations Committee during a hearing about the proposed Keystone XL pipeline project in the Dirksen Senate Office Building on Capitol Hill March 13, 2014 in Washington, DC. The committee heard testimony from proponents and opponents of the pipeline, which would carry tar sands oil from Canada to the United States for production and refinery. (Photo by Chip Somodevilla/Getty Images)
