In October 2017, Wyden was one of nineteen senators to sign a letter to Administrator of the Environmental Protection Agency Scott Pruitt questioning Pruitt's decision to repeal the Clean Power Plan, asserting that the repeal's proposal used "mathematical sleights of hand to over-state the costs of industry compliance with the 2015 Rule and understate the benefits that will be lost if the 2017 repeal is finalized" and science denying and math fabricating would fail to "satisfy the requirements of the law, nor will it slow the increase in frequency and intensity of extreme weather events, the inexorable rise in sea levels, or the other dire effects of global warming that our planet is already experiencing."