More than 99.9% of peer-reviewed scientific papers agree that climate change is mainly caused by humans, according to a new survey of 88,125 climate-related studies.
The research updates a similar 2013 paper revealing that 97% of studies published between 1991 and 2012 supported the idea that human activities are changing the Earth’s climate. The current survey examines the literature published from 2012 to November 2020 to explore whether the consensus has changed.
said Mark Linas, a visiting fellow in the Alliance for Science at Cornell University and first author of the paper.
“More than 99% consensus on human-caused climate change is in the peer-reviewed scientific literature,” said Benjamin Holton, Dean of Cornell’s College of Agriculture and Life Sciences and one of the study’s authors, which was published Oct. Environmental Research Letters.
Despite these findings, public opinion polls as well as opinions of politicians and public representatives point to false beliefs and claims that there is still considerable debate among scientists about the true cause of climate change. In 2016, the Pew Research Center found that only 27% of adults in the United States believed that “nearly all scientists” agreed that climate change is caused by human activity, according to the paper. A 2021 Gallup poll indicated a deep partisan divide in US politics over whether the warming observed on Earth since the Industrial Revolution is primarily caused by humans.
“To understand where there is a consensus, you have to be able to quantify it,” Linas said. “This means scanning the literature in a coherent, non-random manner in order to avoid the circulation of selected papers, for which these arguments are often carried out in the public domain.”
In the study, researchers began by examining a random sample of 3,000 studies from a data set of 88,125 English-language climate papers published between 2012 and 2020. They found that only four of the 3,000 papers question human-caused climate change. “We knew that [climate skeptical papers] It was very small in terms of its occurrence, but we thought there was still more in the 88,000,” Linas said.
Co-author Simon Berry, a UK-based software engineer and Alliance for Science volunteer, created an algorithm that searched for keywords from papers the team knew were skeptical, such as “sun,” “cosmic rays,” and “natural cycles.” The algorithm was applied to all over 88,000 sheets of paper, and the software arranged them so that the skeptics came higher in order. They found many of these offending sheets near the top, as expected, with diminishing returns at the bottom of the list. Overall, the search yielded 28 papers were implicitly or explicitly skeptical, all published in secondary journals.
If the result of 97% of the 2013 study still leaves some doubt about scientific consensus about human impact on climate, the current findings go so far as to allay any uncertainty, Linas said. “That should pretty much be the last word,” he said.
Support for the Science Alliance is provided by the Bill & Melinda Gates Foundation.
Material provided by Cornell University. Original by Krishna Ramanujan, courtesy of the Cornell Chronicle. Note: Content can be modified according to style and length.