Scientists love arguments and counter-arguments. Even when they arrive at a consensus, they remain open to evidence that could force them to change their minds. That is perhaps why, despite a consensus among 97% climate scientists that humans are causing global warming, some people believe that the 3% who are against it may have a consensus-shattering study up their sleeve.
To see if there is indeed such a possibility, Rasmus Benestad of the Norwegian Meteorology Institute and his colleagues set out to replicate the results from the tiny sliver of studies that believe humans are not responsible for climate change.
Their results, published in Theoretical and Applied Climatology, show that all of the chosen 38 studies had some, often serious methodological flaws. If these contrarian studies are corrected, their new conclusions would probably end up agreeing with the consensus—or be inconclusive.
The most common methodological flaw is “cherry-picking.” For instance, a 2011 paper claimed that solar and lunar cycles are enough to explain the warming the planet has seen. However, environmental scientist Dana Nuccitelli and co-author of the study explains that if the model used data for 6,000 years instead of 4,000 years, their conclusion is muddled up.
The other serious charge is that of “curve-fitting,” where researchers use only those variables that help support the conclusion they wish to draw. For instance, a 2011 study claimed that orbital cycles of Jupiter and Saturn may explain Earth’s warming trend. Such practices, Nuccitelli says, displays a clear lack of plausible physics.
Of course, the 38 papers examined are not the sum total of papers that go against the consensus—Benestad and Nuccitelli could themselves be accused of cherry-picking. However, they pre-empt the charge by accepting the limitation and saying that they chose a sample of the most visible contrarian studies.
They also admit that if studies that do agree with the consensus are picked apart this way, they may also show some of these weaknesses. However, the saving face is that at least they all agree on a single cause behind global warming. Nuccitelli’s conclusion is telling:
If any of the contrarians were a modern-day Galileo, he (or she) would present a theory that’s supported by the scientific evidence and that’s not based on methodological errors. Such a sound theory would convince scientific experts, and a consensus would begin to form. Instead, as our paper shows, the contrarians have presented a variety of contradictory alternatives based on methodological flaws, which therefore have failed to convince scientific experts.
Scientists, like all other humans, can be wrong.
Indeed, given the number of subjective choices they have to make, it is should not be surprising when they do go wrong. However, with each study, they inch closer towards the truth. Hence, the most rigorous assessment by the Intergovernmental Panel on Climate Change concluded in 2014 that it is more certain than ever that humans are causing global warming.
Still, there will be always be some who would poke holes at scientific consensus without understanding the facts: