Almost 16 years after Harvard researcher Naomi Oreskes first documented an overwhelming scientific consensus on climate change, a research team confirmed that 97 percent of climate scientists agree that human-caused climate change is happening.
The study, published Tuesday, brought together 16 scientists, including seven authors of consensus studies that documented similar conclusions over the years despite varying research approaches. While reaching this so-called “consensus on consensus,” authors concluded that scientific agreement on human-caused climate change is “robust” with a range of 90 to 100 percent, depending on the question and methodology.
“It’s important to have [it] on the record,” said Will Cantrell, professor of physics at Michigan Technological University, who was not part of the study. “I don’t think any one study is going to change a lot of people’s minds, but it’s better to have the information than to not have it,” he told ThinkProgress.
Techniques used to assess expert views on human-caused climate change include analyzing peer-reviewed climate papers, surveying members of the relevant scientific community, compiling public statements by scientists, and mathematically analyzing citation patterns. For this paper, authors used a statistical technique called meta-analysis, which is a way to combine the findings from independent studies, and essentially did a meta-study of meta-studies.
The study also shows that the higher the level of expertise in climate science, the higher the agreement that global warming is caused by humans. “The consensus on consensus is very strong,” said Sarah A. Green, co-author and professor at Michigan Technological University, in an interview with ThinkProgress. “For me, this topic is deja vu — this consensus has been growing since I was a graduate student in the 80s.”
Yet Green said authors wanted to counter climate skeptics, and rebut a comment paper that criticized a consensus study John Cook, lead author of the study and researcher at the University of Queensland, wrote in 2013. “Not that it is wrong to have questions,” said Green. “It’s wrong to not listen to the answers.”
Richard Tol, who wrote the comment paper, is still unconvinced — despite the rebuttal. “It is good to do the occasional stock take of what we do and do not know. The usual form for that is through literature surveys and meta-analyses rather than consensus estimates like Cook’s,” said Tol, a professor of economics at the University of Sussex in the United Kingdom, via email.
But Tol, who didn’t answer whether he accepts the science of climate change, is not the only consensus skeptic, though he is part of a dying breed. American understanding of human-caused global warming has lagged behind the scientific community, even though the national academies of science from 80 countries have issued statements endorsing the consensus position, and even though 2015 was the hottest year on record. That’s been changing, however. Last March, some 64 percent of adults said they are worried a “great deal” or “fair amount” about global warming, up from 55 percent at that time last year. According to the Gallup poll, concerns about global warming have increased among all party groups since 2015. Moreover, activists are pushing to unveil what they describe as decades of misinformation campaigns funded by fossil fuel interests. Indeed, it’s been widely reported that secret donor networks have funded groups that attack peer-reviewed scientific research.
Meanwhile, 59 percent of the Republican House caucus and 70 percent of Republicans in the Senate deny the scientific consensus that climate change is happening and humans caused it, according to a recent analysis from the Center for American Progress Action Fund. That means more than six in 10 Americans are represented by someone in Congress who denies climate change.
Adam Frank, professor of astrophysics at the University of Rochester, said that disconnection between the consensus and politicians is worrisome. “We are a nation whose national treasure is our prowess of science,” Frank, who wasn’t part of the study, told ThinkProgress. “Once you start downs this road of pushing against science because it has political ramification, then all of science opens up to it.”