The point’s been made before, but I think Mark Kleiman’s explanation of why uncertainty in climate science* makes the case for action stronger rather than weaker was very good and clear. It’s important to note that this doesn’t require an appeal to a completely generalized and hazy “precautionary principle,” it’s implicit in any reasonable concept of cost-benefit analysis.
* Importantly, this is not uncertainty about whether the planet is warming or uncertainty about whether greenhouse gases cause warming. It’s uncertainty about the interaction effects of this dynamic with things like changes to albedo, changes to ocean current, changes in plant life, release of methane gas through melting permafrost, etc. The basic greenhouse gas science is fairly simple, but the climate system as a whole is extremely complicated and hard to model definitively because we don’t have any spare planets to experiment on.