During the 2016 presidential campaign, countless climate experts voiced their concern about Trump, who had infamously called climate change a “hoax” and said it was “created by and for the Chinese.” Trump promised to undo Obama-era environmental laws, bring back coal power, and withdraw from the 2015 Paris climate agreement, in which the world’s nations unanimously agreed to start ratcheting down carbon pollution.
For all these reasons, climatologist Michael Mann wrote in October 2016 that Trump was “a threat to the planet.”
https://thinkprogress.org/trump-presidency-two-years-climate-f23d266c15ac/