I never recall hearing that other than from people strawmanning what the labs were saying.
It's the same as conservatives who tirelessly repeat "In 1995 they told us the world would be underwater by 2015, those climate scientists are full of shit" - no, no one ever said that, you just listen to grifters who only can strawman.
By the way, I don’t think climate denial has (or at least should, though I know Americans like to politicise everything under the sun) anything to do with ‘conservatism’.