Arguing about the existence of climate change as a premise for arguments about political economics is like arguing about the existence of God as a premise for arguments about morality: a waste of time — time that could be better spent advocating for a particular economic or moral position. If a theist justifies eating meat because the Bible says that God instructed humans to be masters over every living thing, a vegetarian would be ill-advised to counter-argue that God does not exist. The vegetarian may more cannily argue that mastery does not mean killing.
Similarly, an advocate for clean air and water and asylum for climate refugees would be hard-pressed to convince a climate change denier of the reality of anthropogenic climate change. Instead, it is more likely that a climate skeptic could be persuaded that we should not deplete and pollute our environment for the profit of the few at the expense of the many, and we should not leave fellow humans stranded without arable land or fresh water — without getting into arguments about the climatological consequences or causes of such problems.
Ultimately, it is not our attitudes toward science or religion that must change, not our metaphysical beliefs, but rather our economic system, our way of relating to nature and other people, that must change from exploitation to equality.