In 2014, Todd Mitchell, Lance's chief of staff, characterized him as a skeptic on human involvement in climate change, saying that he believes that "climate change is occurring and human activity is a contributing factor. But it's uncertain how much of the warming is attributable to humans and how much is attributable to other factors." On December 1, 2015, he voted for S.J. Res. 24, to repeal the Clean Power Plan rules published by the EPA on October 23, 2015, that would have established the first national carbon dioxide emission guidelines for existing power plants. At a town hall in April 2017, he embraced the need to address man-made climate change.