A few days ago, I mentioned a paper that had looked at climate model simulation of clouds and found that the ones that did the best job of this narrow task produced the highest predictions of temperature rises. As I noted at the time this means that one can paraphrase the findings as "best cloud simulators are worst temperature predictors" but, as is normal in these circumstances, the headlines were all about global warming being "worse than we thought".
Yesterday Nature published a similar paper, this time looking at the El Nino phenomenon. It seems that if you take the models that best simulate extreme rainfall they predict that extreme Ninos will take place much more frequently in future, with all the floods and droughts and the like that accompany them.
The team identified 20 climate models — half of those available — that were capable of simulating extreme rainfall. They then used the models to compare the occurrence of extreme El Niños in a control period, 1891 to 1990, versus a warmer period extending from 1991 to 2090. Although the total number of El Niño events decreased, 17 out of the 20 models predicted more major El Niño events, with the average frequency increasing from once every 20 years to once per decade.
As an aside, it's notable that only half of the climate models were considered capable of simulating extreme rainfall, so one can reasonably wonder why we should base public policy on computer simulations that can't get even basic phenomena like heavy rain correct. One can also wonder at the paper's use of CMIP5 model runs, which don't incorporate the IPCC's latest estimates of aerosol forcings, and a perturbed physics ensemble, presumably the Sexton one, which has problems of its own. This is speculation though and I'll need to confirm when I get hold of the paper.
Of more immediate relevance to my point is the similarity in approach to the earlier paper - I think what we have here is a case of "the least absurd rainfall simulators predict a devastating increase in El Nino". Now you would think that, this being the case, the writers would have exercised a little restraint, perhaps mentioning uncertainties here and there. But not a bit of it. Here are a few of the headlines: