It doesn't matter that most Christians don't believe it. Most Muslims don't do violent attacks on civilians, yet they all seem to pay the price either in their home countries or in the US.
It seems world-wide, a hard-right extremist subset of religious believers are ruining things for everyone else.
It's actually not that particularly relevant what Christians believe exactly (and they do believe that the world will be destroyed as-is), what's relevant is what the actual crazy book says.
And if you believe the book that says crazy things, or perhaps you cherry pick and interpret the crazy things to your liking and convenience - his point stands.
And the crazy book days say that the non Christians will burn (for eternity?) in flames of hell and that great many Christians won't be able to get through the narrow gate (and also be tortured to death in hot lava).
You might have a point about Catholics in terms of sheer numbers, but... the only people still listening to Catholics are right wing chuds and Warhammer fans - and even the former aren't listening anymore because the Pope is too "woke" for them. The days when the Pope's word mattered are long, long gone. What happened when he gave his encyclical on AI? It made headlines for a day or two then the world proceeded to ignore the silly hat man as usual.
So I stand by my point. The Christians who matter as far as climate change policy is concerned don't care because as far as they're concerned this world just exists for God to burn anyway.