This is a NYT article on creating a legitimate cost benefit analysis for climate change. This has become the underpinnings of our government’s policies.
Regardless of the extremes weighting in this is honest math. Revesz puts the math together and the legal arguments that matter to work.
Because the impacts of climate change are down the road, there is an unknowable tunable parameter in any calculation of the monetary cost of climate change. The discount rate. How much is a dollar tomorrow worth today. The magic of compound interest is at work here, small changes in the discount rate give you vastly different present values of future costs. Once you pick a discount rate, the math is solid.
The uncertainties in the physical climate pale in comparison to forecasting the economy 50 years out. The physics is clear, we are putting CO2 into the air, CO2 warms the planet, and we are emitting enough CO2 to produce large impacts. Putting an exact dollar amount on those impacts is a fools errand. Pretending that because we can’t accurately predict the cost means the cost is zero is idiotic.
Revesz is using the past 30 years as a guide. Not patently stupid and it has the benefit of being an objective rule rather than pulling a number out of thin air. In the end, we are dealing with risk and uncertainty, less on the physical side, much more on the economic side. Do you feel lucky?
In any forecast of future profits or benefits there is a lot of speculation as well.