Democratic presidential candidates Joe Biden and Elizabeth Warren offered proposals during Wednesday’s climate change town hall on CNN that mirrored what former Secretary of State Hillary Clinton described as her biggest mistake during her 2016 campaign. Biden and Warren both attacked coal mining and fossil fuels during the 7-hour long forum, suggesting that eliminating one of the largest sources of energy in the United States would substantially help the environment. “We’ve got to shut down” all coal-fueled power plants, Biden asserted during his portion of the town hall.