I’m not sure that’s a valid way to do the calculation. A net benefit is not a cost. A net benefit is a benefit. A proper analysis looks at costs and benefits

I’m not sure that’s a valid way to do the calculation. A net benefit is not a cost. A net benefit is a benefit. A proper analysis looks at costs and benefits together and calculates the net result. There are inherent damages (externalities) to the way that we do things, but the correct analysis is to examine the substitute ways to do things and what their relative (increased) costs are in exchange for decreases damages. So you can say we can reduce A amount of pollution, which is expected to save B lives, at an increased cost of C, which drives D amount of people into unemployment or poverty. Looking at one thing without examining the overall effect on the whole system is pretty pointless, even inhumane to a point.