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What percentage of climate scientists agree humans are the primary cause of recent global warming?
Executive summary
Multiple peer-reviewed reviews and major science organizations report that an overwhelming majority of climate scientists say humans are the primary cause of recent global warming — commonly cited figures range from about 90% up to “greater than 99%” depending on how the question and sample are defined (examples cited by NASA and academic reviews) [1] [2]. Recent communications research and public-opinion reports note commonly used headline numbers such as 97% and ranges like 90–100% in summaries of the literature, and emphasize that public estimates of the consensus are usually much lower than what scientists report [3] [4].
1. Consensus magnitude: what the major reviews say
Large literature reviews and citation analyses have repeatedly found very high agreement among climate scientists that recent warming is primarily human-caused. NASA’s climate-consensus page cites multiple peer‑reviewed studies and summarizes findings including analyses that report “greater than 99% consensus” in some formulations and other studies clustering near the high 90s depending on methods [1]. A classic peer‑reviewed analysis published in Science found essentially no published papers that denied the mainstream attribution, reporting strong agreement with IPCC conclusions among published work [2].
2. Why numbers differ: question wording, who you count, and methodology
Different studies produce different percentages because they define “climate scientists” and “human cause” differently. Some analyses count authors of peer‑reviewed literature and rate papers’ positions (yielding very high percentages), while some surveys ask self‑identified scientists about their views (which can produce slightly different totals) [2] [1]. Communication and psychology studies note that the same literature can be summarized as “97%” in messaging experiments, or as ranges like 90–100% in reviews of multiple studies — both are used in public reporting [3] [4].
3. What the communication literature finds about public perception
Researchers report that telling people about the scientific consensus increases estimates of how many scientists agree and modestly raises belief that humans cause warming, although the effect on support for specific policies can be small [5]. A large, multi‑country study and related messaging work used a 97% figure in experiments and found it moved perceptions; other communicators cite ranges up to 99.9% in summaries [3] [6] [5].
4. Institutional positions and the broader scientific community
Major scientific bodies — national academies, the IPCC, and professional societies — explicitly state that human activities, primarily fossil fuel burning, are the dominant cause of recent warming. NASA’s FAQ and other institutional pages link these organizational statements to the consensus reflected in the literature [7] [1]. Union of Concerned Scientists and similar organizations frame the consensus succinctly: warming is happening and is caused primarily by the burning of oil, gas and coal [8].
5. Limits and disputes in the reporting
Available sources do not claim a single, universally agreed percentage because methodology matters; some sources highlight “greater than 99%,” others use 97%, and some reviews give a 90–100% span when aggregating multiple studies [1] [3] [4]. The academic literature emphasizes that consensus statements rest on evidence and methods, not vote counts, and that differences in reported numbers reflect sampling, definitions, and analytical choices [2] [1].
6. Why the distinction matters for policy and debate
Scientists emphasize evidence and attribution studies (connecting greenhouse gases to observed warming) rather than consensus tallies as the basis for policy; nevertheless, consensus figures are used to correct public misperceptions and build trust in the scientific foundation for action [1] [5]. Communication research shows consensus messaging helps align public beliefs with the scientific majority, but changing policy support often requires additional messaging or context [5] [3].
7. Bottom line for readers
If your question is “what percentage of climate scientists agree humans are the primary cause of recent warming?” the best-supported summary across institutional summaries and peer‑reviewed reviews is that an overwhelming majority do — commonly reported summary figures include about 97% and upwards to “greater than 99%,” while aggregated reviews report ranges such as 90–100% depending on how the question and sample are defined [3] [1] [4]. The underlying evidence and institutional statements — not just the headline percentage — are what scientific organizations point to when framing the certainty that human activity is the dominant driver of recent global warming [7] [2].