Pielke Jr 2011 "by 2100... climate change may increase the overall damage from extreme events by $84 billion or 0.015 percent of world GDP"
Romm 2009 "Scientists find “net present value of climate change impacts” of $1240 TRILLION on current emissions path."
We note with little surprise that it is not the other way around, that Pielke's number is not vastly greater than Romm's.
I think what this is is not a story of who is right and who is wrong.
Now on one hand, we are comparing a total vs an annual rate, so that accounts for two orders of magnitude there. But we are still comparing 1240 trillion to something like 8.4 trillion; consider that uncertainty by comparison to the uncertainty in climate sensitivity (between 2 C and 4 C by most accounts.)
My question is this: why are those carping about uncertainty and undeveloped science aiming their fire at climate science rather than economics? I've asked it before, but it's nice to put some numbers on it. Climate science is the best constrained part of the carbon policy question. The carbon policy arguments should be completely decoupled from arguments about physical climatology until the impacts and mitigation people get their act together.
A discrepancy like this on a matter of such importance is bad enough. That the wrong discipline is getting the blame is just ridiculous.
The only thing we can be sure of about the future is that it will be absolutely fantastic. So if what I say now seems to you to be very reasonable, then I have failed completely. Only if what I tell you appears absolutely unbelievable, have we any chance of visualizing the future as it really will happen.
- Arthur C. Clarke (h/t Brin)