Bernie Sanders introduces 'Keep it in the Ground' bill (11 images)

Democratic presidential candidate Sen. Bernie Sanders (I-VT) attends a press conference where he and Sen. Jeff Merkley (D-OR) introduced the "Keep it in the Ground" bill to help combat climate change by curbing carbon emissions and promote a change to renewable fuels, on Capitol Hill in Washington, D.C. on November 4, 2015. Photo by Kevin Dietsch/UPI

Democratic presidential candidate Sen. Bernie Sanders (I-VT) attends a press conference where he and Sen. Jeff Merkley (D-OR) introduced the "Keep it in the Ground" bill to help combat climate change by curbing carbon emissions and promote a change to renewable fuels, on Capitol Hill in Washington, D.C. on November 4, 2015. Photo by Kevin Dietsch/UPI

Democratic presidential candidate Sen. Bernie Sanders (I-VT) walks to an event where he will introduce legislation to help combat climate change, on Capitol Hill in Washington, D.C. on November 4, 2015. Photo by Kevin Dietsch/UPI

Democratic presidential candidate Sen. Bernie Sanders (I-VT) speaks to the media as he leaves a press conference where he and Sen. Jeff Merkley (D-OR) introduced the "Keep it in the Ground" bill to help combat climate change by curbing carbon emissions and promote a change to renewable fuels, on Capitol Hill in Washington, D.C. on November 4, 2015. Photo by Kevin Dietsch/UPI