When people talk about general relativity they don't refer to the scientific consensus behind the theory? It stands up to scrutiny because there are numerous reproducible experiments lending to its validity along with some very solid mathematics to back it up. The science behind climate change is very hard to create experiments for, however, and so we must lean heavily on computer simulated models (which, by the way, are rarely used to prove much of anything in the hard sciences). Thus, you hear a lot more about "consensus" than you would otherwise.