Drawbacks of Apriorism in Intergovernmental Climatology

Abstract

IPCC (2013) replaces climate models' over-predictions of near-term global warming with its “expert assessment” that warming in the next 30 years may scarcely exceed that of the last 30. Medium-term anthropogenic forcings and global temperature projections have been all but halved since 1990. There has been no global warming this millennium. Nevertheless, at the intergovernmental level, an aprioristic approach to modeling, over-confidence in models' predictive skill, and serial misrepresentation of results has prevented agreement on what fraction of recent warming was anthropogenic, how much warming we may cause and at what risk or net welfare loss, if any. The cost of mitigating predicted warming exceeds that of later adaptation by 1–2 orders of magnitude. Given governments' pre-existing monopsony of climatology, the question arises whether intergovernmental science is either necessary or desirable.