Environmental scientist Dana Nuccitelli and his colleagues recently took a look at several scientific papers that dispute man-made climate change. What they found was disturbing. But before we discuss their results, let’s first get into why anthropogenic (man-made) climate change is such a controversial topic in the first place.
The 97 Percent Consensus on Man-Made Climate Change
Back in May, I spoke to John Cook, the founder of Skeptical Science and the lead author of a 2013 paper that quantified the consensus on man-made global warming in scientific literature. In the paper, Cook and his colleagues analyzed nearly 12,000 peer-reviewed climate papers published over a 20-year period and determined that 97.1 percent of them say that humans are significantly affecting global warming.
“It’s happening, it’s us, and the impacts are serious,” said Cook.
Yet despite this overwhelming consensus, the fossil fuel industry and many politicians indebted to it have pushed an agenda of climate change skepticism. Billionaire industrialists Charles and David Koch have pushed it, former Governor of Alaska Sarah Palin has pushed it, most of the Republican party pushes it and all but one of their presidential candidates is still pushing it today.
The reason why these folks are so opposed to what science is unequivocally telling us, said Cook, is because it not only places the blame squarely on humanity’s shoulders, it also requires us to change the way we’ve done things for the past 100 years.
“Whenever there’s been an attempt to change the way things are done,” said Cook, “to upset the status quo, there’s always been the greatest resistance from the people who have the most to lose. In the case of climate change, the solutions to climate change involve regulation of polluting industries.”
But of course these are also the people that have the power and the money to spread their message, which has led to the mistaken belief among the American public that there is some kind of debate over whether climate change is an anthropogenic problem or not. Last year, Yale found that 66 percent of US voters actually believe climate change is happening. Pew reports that 35 percent of the public believes there is no solid evidence of global warming. In the same poll, 18 percent of the public believes warming is occurring but that it’s part of the Earth’s natural state.
Presidential candidate and avowed science denier Ted Cruz has suggested that those who deny man-made climate change are the Galileos of this era, a minority shouting against a bloated conspiracy of wrongness. But of course Galileo was shouting the findings of his dedicated, unbiased research, which were soon replicated by other scientists of the age.
And that is a very important distinction. Replication is an essential part of the scientific process, for it allows other researchers to examine the work and either dispute or confirm the results. And that is precisely what Dana Nuccitelli and his colleagues set out to do when they investigated 38 of what he dubs “climate contrarian” scientific papers. Their analysis can be read here. The paper’s authors include John Cook, Nucitelli, Rasmus Benestad, Stephan Lewandowsky, Hans Olav Hygen, Rob van Dorland and Planet Expert Katharine Hayhoe.
Fact-Checking the Skeptics
As John Cook explained back in May, skepticism is a good thing in the scientific realm. Skepticism keeps us questioning, keeps us discovering, keeps us improving the established ways of doing things. That’s why it’s good to remain skeptical and even better to experiment. However, when over 97 percent of scientists are saying the same thing, it does raise the questions: What are the two percent saying, and why are they saying it?
In his recent article in The Guardian, Nuccitelli explains how he and others attempted to replicate the results of papers that claim climate change isn’t due to the 32.1 billion tons of carbon dioxide being belched into the atmosphere every year. It turns out those papers have some serious flaws.
The most common flaw? Cherry-picking. “We found that many contrarian research papers omitted important contextual information or ignored key data that did not fit the research conclusions,” Nuccitelli wrote.
For example, a 2011 paper by Humlum et al. posits that climate change is being affected by the cycles of the moon and the sun. Nuccitelli and his colleagues found that the Humlum model worked “reasonably accurately” for the 4,000-year period they considered, but not for the 6,000 years of earlier data that they flat-out ignored. “The authors argued that their model could be used to forecast future climate changes,” wrote Nuccitelli, “but there’s no reason to trust a model forecast if it can’t accurately reproduce the past.”
In paper after paper, the researchers found that climate contrarian papers were ignoring inconvenient data and sometimes even disregarding the laws of physics to reach their conclusions. In the abstract of their analysis, the authors write that many of the papers’ shortcomings were due to “insufficient model evaluation” that resulted in conclusions “that are not universally valid but rather are an artifact of a particular experimental setup.”
The most damning blow against these papers may be the fact that, of the 38, writes Nuccitelli, “there is no cohesive, consistent alternative theory to human-caused global warming.” Some say it’s the sun that’s causing global warming, some say it’s the planets, some say it’s the ocean, but none of them agree with each other, whereas 97.1 percent of papers say it’s those billions of tons of CO2 and related greenhouse gases.
Nuccitelli also points out that going back through papers that support man-made global warming would “undoubtedly” reveal some errors in methodology. But of the 38 papers studied, “these types of flaws were the norm, not the exception.”
Of course, I don’t expect this damning evidence against the skeptics to stop any of them from throwing snowballs at us, or from denying the fact that 2015 is already well on its way to topping 2014 as the hottest year on record.
If you’d like to learn more about Nuccitelli et al.’s findings, check out the supplementary material to their paper here.