Skip to content

Judith Curry: Humpty Dumpty Cannot Be Put Together Again

Judith Curry, Climate Etc.

I don’t think the IPCC can be fixed or reinvented in a way that is useful.


The IPCC is showing typical signs of middle age, including weight gain, a growing rigidity of viewpoint, and overconfidence in its methods. It did a great job in the early days, but it’s become ritualized and bureaucratic, issuing big bulk reports that do little to answer the hard questions facing policymakers.  – David Keith, as cited by Fred Pearce

Well, it seems the IPCC is no longer a ‘delinquent teenager.’

Fred Pearce has written an interesting article at Yale Environment 360 entitled Has the U.N. Climate Panel Now Outlived Its Usefulness?

The subtitle  is ‘Some scientists are saying that the latest report from the IPCC is overly conservative and fails to mention some of the more worrisome possible scenarios.   The panel, they contend,  is no longer fulfilling its mission of informing policy makers of the risks of global warming.’

While Pearce is clearly in the camp of ‘our perilous greenhouse future,’ he invariably provides thoughtful and new insights in his writing.  The parts of his IPCC article that I found particularly provocative are excerpted below:

Some of those involved in the report process believe the natural caution among scientists — coupled perhaps with a wish not to repeat some exaggerations that marred some previous IPCC reports, and the effect of politicians looking over their shoulders — has created a report that is overly conservative, even biased, in its conclusions. Rather than lowering its expectations of warming, these scientists say, perhaps the panel should be raising them. 

Some “scary scenarios” arising from possible positive feedbacks — in which nature amplifies man-made warming — have been left out of the model projections on which the IPCC’s headline forecasts are based. Surely, some critics say, it is the scary scenarios that politicians need to know about if they are to do their duty under the UN climate change convention and act together to prevent “dangerous climate change.” Even the U.S. signed that, under George Bush senior in 1992. […]

JC comments:  While coming at this from a very different perspective than my own IPCC diagnosis – permanent paradigm paralysis, we reach some similar conclusions.  I particularly like posing this in terms of ‘fitness for purpose.’   Pearce also emphasizes the other side of the two-edged sword of uncertainty, namely that we have failed to focus on articulating the plausible worst case scenarios that could emerge in the 21st and even 22nd centuries associated with a combination of natural and anthropogenic climate change.

With regards to Pearce’s question:

It may do good science, but does it deliver what policymakers need?

I have argued that the IPCC consensus seeking process is getting in the way of doing the science that is most needed to support the needs of policy makers, namely decadal variability on regional scales and also the plausible worst case scenarios.

I don’t think the IPCC can be fixed or reinvented in a way that is useful.

Full story