The unavoidable conclusion: we should be discussing development pathways, and not simply carbon dioxide.
The point of this post is not to argue against mitigation, but to highlight the importance of adaption — a topic generally unpopular with the “green” special interests. Nor is the goal to argue that GDP/capita is the only important valuation of policy options. That said, I found Roger Pielke, Jr.’s review of the new IPCC report’s economic scenarios quite interesting.
A caution/clarification: Roger uses a range of estimates of the “GDP costs for year 2100” of the base case [business as usual] of 5% [IPCC] to 20% [Stern Review high range]. Personally, I’ve examined all these scenarios using the single 5% estimate. There are a lot of problems with the Stern 20% figure — see this resource post for some of the analysis.
With that simplification, I could crudely summarize the point of Roger’s post as “by 2100 the global GDP/capita impact of decisions about adaption/development are roughly 70 times as important as mitigation decisions”.