You're correct that, generally speaking, policy debates should not appear one-sided (https://www.lesswrong.com/posts/PeSzc9JTBxhaYRp9b/policy-deb...). We should put very little prior weight on the hypothesis that one side is actual cartoon villains, from a children's TV show, with the simple goal of looting the system and no concern for how much of the future they destroy while doing so.

However, to be effective reasoners, we can't assign that hypothesis 0 prior probability; and once sufficient evidence has come in, our posterior distribution must shift.

I don't think there's any reasonable case for shutting down an early warning system which costs around the price of the new white house thunderdome every decade, and instead waiting to find out AMOC has collapsed when Scotland is hemmed in by year-round ocean ice and agriculture is impossible in Western Europe.

Stranded assets alone, in the latter case, will easily run to hundreds of billions. Knowing when to change crop profiles, reinsuance schedules, etc., would save much more.