Climate Change Economics

I assessed five statements in the Summary for Policy Makers (SPM) of the Fifth Assessment Report (AR5) of Working Group II (WG2) of the Intergovernmental Panel on Climate Change (IPCC). The IPCC’s assessment of the impacts of climate change on agriculture all but ignores human agency and human ingenuity. The statement in the SPM on violent conflict is much stronger than in the chapter and indeed the literature. AR5 ignores the literature on the impacts of climate change on cold-related mortality and morbidity. On poverty traps, WG2 reaches a conclusion that is not supported by the cited papers. The total impacts of climate change were assessed in four subsequent IPCC reports. Although there are no statistically significant differences between the assessment periods in the underlying literature, the subsequent SPMs reach very different conclusions. In sum, the IPCC has yet to reach the quality that one would expect from a gold standard.