In the midst of a stifling Washington, D.C. summer two years ago, former President Obama appeared in the White House to paint a grim picture of the challenge global warming posed to the country. The August 2015 press conference, at which Obama announced the Clean Power Plan, was supposed to be held on the White House’s South Lawn, but it was moved indoors at the last moment, after officials decided it was too hot to do the event outside.