IS THE IPCC’s 5THASSESSMENT A DENIER OF POSSIBLE MACROECONOMIC BENEFITS FROM MITIGATING CLIMATE CHANGE?

This review summarizes what we know about the macroeconomics of mitigating climate change over the period 2010 to 2100 as presented in the 2014 IPCC Working Group III report. The review finds that little more, if anything, has been learned about the macroeconomics of mitigating climate change over the long run since the 2007 IPCC report. Furthermore, while the 2014 report is quite self-critical about the serious weaknesses in its methodologies, the self-criticisms are not explicitly taken into account when the net macroeconomic costs of mitigation are reported. Nor do the research teams that run the integrated assessment models relied on in the report utilize any systematic methodology for assessing the inherent uncertainty in the macroeconomic results reported. Thus, the basic quantitative “findings” are misleading — and, perhaps, even deceptive — in part because they appear to preclude the possibility of large macroeconomic benefits from mitigating climate change.