Curry began to find other examples where she thought the IPCC was “torquing the science” in various ways. For example, she says, “a senior leader at one of the big climate-modeling institutions told me that climate modelers seem to be spending 80 percent of their time on the IPCC production runs and 20 percent of their time developing better climate models.” She also asserts that the IPCC has violated its own rules by accepting nonpeer-reviewed papers and assigning high-status positions to relatively untested scientists who happen to feed into the organization’s “narrative” of impending doom.
Climate skeptics have seized on Curry’s statements to cast doubt on the basic science of climate change. So it is important to emphasize that nothing she encountered led her to question the science; she still has no doubt that the planet is warming, that human-generated greenhouse gases, including carbon dioxide, are in large part to blame, or that the plausible worst-case scenario could be catastrophic. She does not believe that the Climategate e-mails are evidence of fraud or that the IPCC is some kind of grand international conspiracy. What she does believe is that the mainstream climate science community has moved beyond the ivory tower into a type of fortress mentality, in which insiders can do no wrong and outsiders are forbidden entry.
Uncertainty and Science
Curry is not alone in criticizing the IPCC and individual climate scientists; in the wake of Climategate, an error about glacial melting in an IPCC report, and accusations of conflicts of interest involving IPCC chair Rajendra K. Pachauri, bodies ranging from the U.N. to the British government to individual universities on both sides of the Atlantic launched investigations. None found evidence of fraudulent science—including, most important, a probe by the InterAcademy Council (IAC)—a network of the U.S. National Academies of Science and its counterparts around the world. Although it found no major errors or distortions, it reported that the IPCC’s procedures have failed to change adequately with the times and that in some cases the body has not enforced its own standards rigorously.
Stripped of incendiary words, the central issue that concerns Curry also happens to be the key problem in translating climate science into climate policy. The public at large wants to know whether or not climate is warming, by how much and when, and they want to know how bad the effects are going to be. But the answers scientists give in papers and at conferences come couched in a seemingly vague language of confidence intervals and probabilities. The politically charged nature of the issue seems to have made some scientists reluctant to even mention anything to the public about “uncertainty” for fear that the likes of Oklahoma’s Senator James “greatest hoax ever perpetrated on the American people” Inhofe and other politically motivated skeptics will continue to use the word as a blunt instrument against the whole enterprise of climate science—that because the scientists do not know everything, they know nothing.
The uncertainty lies in both the data about past climate and the models that project future climate. Curry asserts that scientists haven’t adequately dealt with the uncertainty in their calculations and don’t even know with precision what’s arguably the most basic number in the field: the climate forcing from CO2—that is, the amount of warming a doubling of CO2 alone would cause without any amplifying or mitigating effects from melting ice, increased water vapor or any of a dozen other factors.
Things get worse, she argues, when you try to add in those feedbacks to project likely temperature increases over the next century, because the feedbacks are rife with uncertainty as well: “There’s a whole host of unknown unknowns that we don’t even know how to quantify but that should be factored into our confidence level.” One example she cites is the “hockey stick” chart showing that current temperatures are the warmest in hundreds of years. If you are going to say that this year or that decade is the hottest, you had better have a good idea of what temperatures have actually been over those hundreds of years—and Curry, along with many skeptics, does not think we have as good a handle on that as the scientific community believes.