It will never be a death blow, no matter what the truth is.
Look at Scientologists as a perfect example. People actually pay millions of dollars to an organization founded by a science fiction writer who blatantly claimed the best way to get rich is to invent your own religion. They’re giving millions of their own hard earned dollars firmly believing that an alien is entombed in one of our volcanoes.
If intelligent people can be suckered into believing our souls are infected with aliens by a crackpot sci-fi writer then many more will believe in global warming, no matter how much proof is shoved in their faces.