The Consensus Handbook

The document argues that while 97% of climate scientists agree that humans are causing global warming, a significant 'consensus gap' exists in public perception, largely driven by decades of deliberate misinformation campaigns. It identifies perceived consensus as a 'gateway belief' that influences support for climate policy and provides evidence-based communication strategies, such as 'weight-of-evidence' reporting and 'inoculation' against misinformation, to close this gap.

• A synthesis of multiple research methods, including surveys and peer-reviewed paper analyses, indicates that the expert consensus on human-caused climate change is between 90% and 100%, with many studies converging on 97%.
• There is a significant discrepancy between actual scientific agreement and public perception; while the consensus is 97%, the public perceives it as approximately 67%, and only 13% of Americans know the consensus exceeds 90%.
• Perceived scientific consensus acts as a 'gateway belief,' meaning that a person's belief about the level of expert agreement influences their views on whether global warming is real, human-caused, and whether public action is necessary.
• Misinformation campaigns have systematically targeted the scientific consensus since the 1990s, using techniques such as 'fake experts'—portraying non-experts as subject matter experts—and the 'magnified minority' fallacy to create a false impression of scientific disagreement.
• False-balance media coverage, which gives equal weight to mainstream scientists and contrarians, misleads the public into believing a 50:50 debate exists and lowers the perceived consensus.
• Effective communication of the consensus is best achieved through simple, clear numeric statements (e.g., '97%') and visual aids like pie charts, rather than non-numeric phrases or complex debates.
• Inoculation theory suggests that preemptively warning people about misinformation techniques and providing counter-arguments makes them more resistant to future misinformation than debunking after the fact.

APA

Cook, J., van der Linden, S., Maibach, E., & Lewandowsky, S. (2018). The Consensus Handbook. Center for Climate Change Communication. https://climatecommunication.gmu.edu/wp-content/uploads/2023/09/Consensus_Handbook-1.pdf

Chicago

Cook, John, Sander van der Linden, Edward Maibach, and Stephan Lewandowsky. The Consensus Handbook. Center for Climate Change Communication, 2018. https://climatecommunication.gmu.edu/wp-content/uploads/2023/09/Consensus_Handbook-1.pdf.

Wikipedia

{{cite report |last1=Cook |first1=John |last2=van der Linden |first2=Sander |last3=Maibach |first3=Edward |last4=Lewandowsky |first4=Stephan |title=The Consensus Handbook |publisher=Center for Climate Change Communication |date=March 2018 |url=https://climatecommunication.gmu.edu/wp-content/uploads/2023/09/Consensus_Handbook-1.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{cook2018consensus, author = {Cook, John and van der Linden, Sander and Maibach, Edward and Lewandowsky, Stephan}, title = {{The Consensus Handbook}}, institution = {Center for Climate Change Communication}, year = {2018}, month = mar, url = {https://climatecommunication.gmu.edu/wp-content/uploads/2023/09/Consensus_Handbook-1.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }