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Grok 4.5Nov 1, 2026x-ai/grok-4.5-20260708

Are humans responsible for climate change?

Yes, humans are the primary cause of the observed climate change (global warming) since the Industrial Revolution, according to the overwhelming scientific consensus.[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 gases (GHGs) like CO₂, methane, and nitrous oxide since around 1750 are “unequivocally caused by human activities.” The best estimate of human-caused global surface temperature increase from 1850–1900 to 2010–2019 is about 1.07°C (likely range 0.8–1.3°C), while natural drivers contributed roughly –0.1°C to +0.1°C.[1]

Scientific Consensus

•Multiple independent analyses of peer-reviewed literature find extremely high agreement: earlier studies around 97%, with a 2021 survey of over 88,000 climate-related papers (2012–2020) finding greater than 99% (or 99.9%) consensus that climate change is mainly human-caused. Skeptical papers are rare and often in lower-impact venues.[2]
•Surveys of climate scientists and experts show near-unanimous agreement (often 97–100% among the most actively publishing or highest-expertise researchers) that humans are the main driver.[3]
•Leading organizations endorse this, including NASA, NOAA, the U.S. National Academies, the Royal Society, AAAS, AMS, and numerous others worldwide. NASA states there is “unequivocal evidence that Earth is warming at an unprecedented rate. Human activity is the principal cause.”[3]

Key Evidence

•Greenhouse gas increases: Atmospheric CO₂ is about 50% higher than in 1750 (and higher than in at least the last 800,000 years), primarily from burning fossil fuels (coal, oil, gas), with contributions from deforestation and other land-use changes. Isotopic fingerprints confirm the fossil-fuel origin. Methane and nitrous oxide have also risen due to human activities (agriculture, industry, etc.).[4]
•Basic physics and fingerprints: GHGs trap heat (the greenhouse effect). Observed patterns match human influence: warming of the lower atmosphere (troposphere) and surface/oceans, cooling of the upper atmosphere (stratosphere), ocean acidification from absorbed CO₂, and specific changes in extremes, ice melt, and sea level. Natural factors alone (solar variability, volcanoes, internal variability like El Niño) cannot explain the recent warming; solar output has been stable or slightly declining while temperatures rose.[5]
•Climate models: Simulations reproduce the observed warming only when human forcings (GHGs and aerosols) are included. Without them, models show little warming or slight cooling over recent decades.[5]
•Rate and context: Current warming is occurring much faster than natural post-ice-age rates (roughly 10 times faster in some comparisons), and paleoclimate records show no recent natural analog for the combination of rapid GHG rise and warming.[4]

Natural climate variability and past changes (driven by orbital cycles, solar changes, volcanoes, etc.) are well understood and do not account for the post-industrial trend. Human activities dominate the radiative forcing.

Climate has always changed, but the current rapid warming—and its attribution—is distinct because of the scale and speed of anthropogenic GHG emissions. This conclusion is based on multiple independent lines of evidence (observations, physics, models, paleoclimate) and has strengthened over successive IPCC assessments (from “discernible” in the 1990s to “unequivocal” now).

Citations (5)

  1. 1ipcc.chGovernment
    https://www.ipcc.ch/report/ar6/wg1/chapter/summary-for-policymakers/

    Backs: “Yes, humans are the primary cause of the observed climate change (global warming) since the Industrial Revolution, according to the overwhelming scientific consensus.”

  2. 2cornell.eduAcademic
    https://news.cornell.edu/stories/2021/10/more-999-studies-agree-humans-caused-climate-change

    Backs: “Multiple independent analyses of peer-reviewed literature find extremely high agreement: earlier studies around 97%, with a 2021 survey of over 88,000 climate-related papers (2012–2020) finding greater than 99% (or 99.9%) consensus that climate change is mainly human-caused. Skeptical papers are rare and often in…”

  3. 3nasa.govGovernment
    https://science.nasa.gov/climate-change/scientific-consensus/

    Backs: “Surveys of climate scientists and experts show near-unanimous agreement (often 97–100% among the most actively publishing or highest-expertise researchers) that humans are the main driver.”

  4. 4nasa.govGovernment
    https://science.nasa.gov/climate-change/evidence/

    Backs: “Methane and nitrous oxide have also risen due to human activities (agriculture, industry, etc.).”

  5. 5royalsociety.orgAcademic
    https://royalsociety.org/news-resources/projects/climate-change-evidence-causes/

    Backs: “Natural factors alone (solar variability, volcanoes, internal variability like El Niño) cannot explain the recent warming; solar output has been stable or slightly declining while temperatures rose.”