December 19, 2013
The IPCC report acknowledges that almost all of the “historical simulations do not reproduce the observed recent warming hiatus.” Not to worry, it assures us; 15-year pauses just happen, and you can’t really expect the models to simulate such random natural fluctuations in the climate. Once this little slow-down passes, the report maintains, “It is more likely than not that internal climate variability in the near-term will enhance and not counteract the surface warming expected to arise from the increasing anthropogenic forcing” (emphasis in original). In other words, when the warm-up resumes temperatures will soar.
John Christy, a climatologist at the University of Alabama in Huntsville, has come to a different conclusion. Christy compared the outputs for the tropical troposphere of 73 models used by the IPCC in its latest report with satellite and weather balloon temperature trends since 1979. “The tropics is so important,” Christy explains in an email message, “because that is where models show the clearest and most distinct signal of greenhouse warming-so that is where the comparison should be made (rather than say for temperatures in North Dakota). Plus, the key cloud and water vapor feedback processes occur in the tropics.”
When it comes to simulating the atmospheric temperature trends of the last 35 years, Christy found, all of the IPCC models are running hotter than the actual climate.
Well, that’s encouraging. Though actually, I’d prefer global warming to global cooling.