Climate change never used to be a partisan issue. Fossil-fuel industry executives believed in it, for instance, as did the ultra-conservative Margaret Thatcher (
https://www.youtube.com/watch?v=VnAzoDtwCBg&t=449). Someone like Thatcher might as well be an alien today―she had a degree in chemistry, unlike a modern politician, with a degree in law, finance, or business.
Conservatives used to accept expert consensus. They used to believe in civics, even if Thatcherite (and Reaganite) policies played a part in ironing out this disposition. I don't know what happened in the intervening period to turn basic science into such a partisan issue, and I can only assume that it was propaganda sold to us by lobbyists with short term interests.
(I'm using the word 'conservative' to denote
free market conservatism, which is the dominant strain among people who call themselves conservative today. I know there are different types of conservatism that are mutually-exclusive, and I know that people on the left can also be radical free marketers; I don't care for the purpose of this conversation.)