Are humans responsible for climate change?
Yes, humans are the primary cause of recent (post-industrial) climate change. This is the overwhelming conclusion of climate science, based on multiple independent lines of evidence.[1]
The Intergovernmental Panel on Climate Change (IPCC), in its Sixth Assessment Report (AR6, 2021), states: “It is unequivocal that human influence has warmed the atmosphere, ocean and land.” Observed increases in well-mixed greenhouse gas (GHG) concentrations since around 1750 are unequivocally caused by human activities. The likely range of total human-caused global surface temperature increase from 1850–1900 to 2010–2019 is 0.8°C to 1.3°C (best estimate 1.07°C). Well-mixed GHGs contributed a warming of 1.0°C to 2.0°C, other human drivers (mainly aerosols) a cooling of 0.0°C to 0.8°C, while natural drivers contributed roughly –0.1°C to +0.1°C.[1]
Scientific Consensus
Key Evidence
Natural climate variability (El Niño/La Niña, solar cycles, volcanic eruptions, orbital changes) has always existed and continues to influence year-to-year or decadal weather, but it cannot explain the long-term, multi-decadal global warming trend since the Industrial Revolution. Aerosols from pollution have a partial cooling effect that has masked some of the GHG warming.
In short, the evidence from observations, physics, chemistry, paleoclimate data, and modeling converges strongly: human activities are responsible for the bulk of recent climate change. This is as well-established as many other major scientific conclusions (e.g., the link between smoking and cancer). Uncertainties remain in precise regional projections, climate sensitivity details, and future emissions pathways, but the fundamental attribution is robust.
Citations (8)
- https://www.ipcc.ch/report/ar6/wg1/chapter/summary-for-policymakers/
Backs: “This is the overwhelming conclusion of climate science, based on multiple independent lines of evidence.”
- https://news.cornell.edu/stories/2021/10/more-999-studies-agree-humans-caused-climate-change
Backs: “Multiple studies of the peer-reviewed literature find extremely high agreement: a 2013 analysis found ~97% consensus that humans are causing global warming; a 2021 survey of over 88,000 climate-related papers (2012–2020) found greater than 99% consensus (only a tiny handful of skeptical papers).”
- https://science.nasa.gov/climate-change/scientific-consensus/?mod=article_inline
Backs: “Surveys of climate scientists and statements from major scientific organizations (NASA, NOAA, AAAS, American Geophysical Union, National Academies, and nearly 200 others worldwide) affirm that human activities—primarily GHG emissions—are the dominant driver of observed warming since the mid-20th century.”
- https://www.climate.gov/news-features/climate-qa/isnt-there-lot-disagreement-among-climate-scientists-about-global-warming
Backs: “There is no significant disagreement among climate experts on this core point.”
- https://www.climate.gov/news-features/climate-qa/what-evidence-exists-earth-warming-and-humans-are-main-cause
Backs: “Humans emit tens of billions of tonnes of CO₂ annually, far exceeding natural volcanic emissions.”
- https://www.c2es.org/content/climate-science-qa/
Backs: “The observed pattern (tropospheric warming + stratospheric cooling) matches GHG forcing and rules out alternatives like increased solar output.”
- https://www.ipcc.ch/report/ar6/wg1/downloads/faqs/IPCC_AR6_WGI_FAQ_Chapter_03.pdf
Backs: “Detection-and-attribution studies attribute essentially all recent warming to human influence.”
- https://science.nasa.gov/climate-change/evidence/
Backs: “The rate over recent decades exceeds anything in at least the past 2,000 years. Ice cores, tree rings, and other proxies confirm this.”