All eight Senators from CA, AZ, NV, and NM are Democrats, and I assume they "believe in climate change," although I'm not sure whether simply believing is going to make much of a difference.
that was a reply to the suggestion that "maybe" the area should elect senators who believe in climate change. we already have. it wasn't a suggestion that this is actually the answer.
CA and NM both have Democratic "trifectas", and it can reasonably be assumed that they are dominated by anthropogenic climate change believers.
However, I would dispute your claim. The majority of the land (and thus resources) in the SW is under federal, not state control. Ergo, federal representatives play an outsize role in deciding questions central to the SW role in and sufferer of climate change.