Comment by cohomologo

Is "beyond a shadow of doubt" the standard of proof we need to take action? I would advocate for an actuarial standard. (i.e. estimate the probabilities and costs/benefits of various outcomes and take the path with the best expected outcome, while continually updating your probability estimates with new information.) The issue with climate change is not that it is 100% certain, but that the responses require globally coordinated action where every nation is incentive to cheat; and as with other types of economic transition, there are huge inefficiencies if we try to transition too fast (i.e. global recessions required to build the necessary infrastructure as in https://dothemath.ucsd.edu/2011/10/the-energy-trap/). So the downside risk if we fail to act and climate change is real is tremendous.