I tend to give people the benefit of the doubt, and read economic arguments like that in the sense of "we will need to spend a large chunk of our civilisation's

I tend to give people the benefit of the doubt, and read economic arguments like that in the sense of "we will need to spend a large chunk of our civilisation's energy/material output to do this", not "Oh noes! My small, green pieces of paper!" The thing that I worry about with the economic arguments is that the climate and/or ecosystems will reach a tipping point before we get to the point where we need to do something, and that chunk will be > 100%.