I think prediction markets (polymarket et al) get this right. Every question as vague as "is the earth warming" has resolution details which define some way to resolve the question such that all parties (even those with economic interest to disagree) have trouble disputing the outcome.
For a question like the earth warming, it would usually be something like "according to ___.org website on Y date", which in that case the final prediction becomes: will the average temperature in the period from 2016-2026 be greater than Y on ___.org, which is a bit different than the original but easier to arbitrate.
For a question like the earth warming, it would usually be something like "according to ___.org website on Y date", which in that case the final prediction becomes: will the average temperature in the period from 2016-2026 be greater than Y on ___.org, which is a bit different than the original but easier to arbitrate.