Regardless of whether he believes that man made climate change is a thing or not, as a Christian he should still believe he has a moral obligation to take care of the plants and creatures and planet that God created. If he doesn't, then that's his own failing.
"Of course, everyone will claim they respect someone who tries to speak the truth, but in reality, this is a rare quality. Most respect those who speak truths they agree with, and their respect for the speaking only extends as far as their realm of personal agreement. It is less common, almost to the point of becoming a saintly virtue, that someone truly respects and loves the truth seeker, even when their conclusions differ wildly."
-walsh
-walsh