Shortcomings of the IPCC

To milk one final post from today's Science Friday, the program ended by considering the limitations of the Intergovernmental Panel on Climate Change (IPCC, which shared this year's Nobel Peace Prize with Al Gore). IPCC reports have been invaluable in informing public debate about climate change; the nature of the IPCC, however, ensures that its estimates always err on the side of being too conservative, and that its reports rarely include the most up-to-date climate research.

The reason for these deficiencies is that the IPCC, being a U.N. sponsored organization (open to representatives from all member nations of the UN Environment Program), operates through consensus. Every word and figure in the report must be vetted and approved by representatives from dozens of countries. The need to garner consensus pushes the IPCC to be conservative in its forecasts of future warming, perhaps more so than is justified by the evidence; evaluating the latter point is difficult, since by the time the painstaking process of completing an IPCC report is complete, the state of climate research has almost surpassed what is contained in the report.

I am not suggesting that the IPCC can depart from its consensus-driven M.O.; consensus is what has enabled the IPCC's reports to become so authoritative, respected, and uncontroversial. I am suggesting, however, that Bill McKibben is right to warn that basing climate policy solely on IPCC reports may leave us with policies insufficiently robust to forestall future warming (and vulnerable to low-probability but high-impact climate disruptions). Heeding only the IPCC also ensures that our policy proposals will to some extent be based on outdated science. While the Nobel Committee was right to celebrate the work of the IPCC, we should also acknowledge the IPCC's limitations as a forecaster of climate fluctuations and purveyor of climate science.