# The Scientific Consensus on Climate Change The scientific consensus on human-caused climate change is as strong as any in modern science: the planet is warming, and human activity — chiefly fossil-fuel combustion — is the cause. This is not an opinion poll or a political position. It emerged from decades of [[Climate Science]] research across dozens of independent groups and was never imposed from above; it accumulated from the bottom up as the evidence converged. ## How the Consensus Was Measured Multiple independent studies have quantified the agreement. Naomi Oreskes's 2004 analysis of nearly a thousand peer-reviewed abstracts found none that rejected the consensus position. A 2013 study by John Cook and colleagues examined the abstracts of nearly 12,000 papers and found that, among those expressing a position, about 97% endorsed human-caused warming; a parallel survey asking the authors to rate their own papers produced the same figure. Subsequent work, including a 2021 study, found agreement exceeding 99% among actively publishing climate scientists. The convergence of these different methods — abstract analysis, author self-rating, and direct survey — is what makes the 97% figure robust rather than a single contestable statistic. Institutional endorsement is equally one-sided. Every major national academy of science in the world has affirmed the consensus, including the U.S. National Academy of Sciences and the Royal Society, alongside the academies of France, Germany, Japan, China, India, and Brazil. No scientific body of national or international standing dissents. The [[The IPCC]] synthesizes the work of thousands of scientists and has grown more certain with each report, concluding in its Sixth Assessment that human influence is "unequivocal." ## How Consensus Became a Target Because the evidence could not be refuted, the denial movement's strategy shifted to attacking the consensus itself — the subject of [[Merchants of Doubt]] and the broader pattern of [[Science Denial]]. The attacks take recognizable forms. One is the fake-expert gambit: petitions like the "Oregon Petition," padded with signatories who lack relevant credentials, manufacture the impression of a serious scientific split. Another is to reframe consensus as conformity or groupthink — to argue that agreement proves suppression of dissent rather than the weight of evidence. A third is to demand that science work by unanimity, treating the existence of any contrarian as proof the question is open. Communicating the consensus turns out to matter on its own terms. Research on the "gateway belief" finds that informing people of the high level of scientific agreement increases their acceptance of the underlying facts — which is precisely why [[Frank Luntz]] advised in 2002 that Republicans should emphasize "lack of scientific certainty," reasoning that if the public came to believe the science was settled, support for action would follow. The fight over the consensus was never really about the science; it was about whether the public would be allowed to know how settled it is. ## Connections The consensus is institutionalized in [[The IPCC]] and rests on the converging evidence cataloged across [[Climate Science]]. The campaign against it is the core of [[Climate Change Denialism]] and a flagship case of [[Science Denial]]. For the field overview, see [[Climate Science]].