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.” Widespread and rapid changes have occurred across the climate system. The likely range of 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), which accounts for essentially all the observed warming. Well-mixed greenhouse gases (mainly CO₂ from fossil fuels) contributed the bulk of the warming, partially offset by aerosols and other factors; natural drivers (solar, volcanic) and internal variability contributed negligibly (±0.1–0.2°C).[1]

Scientific Consensus

•Multiple independent analyses of the peer-reviewed literature find >99% agreement that recent climate change is mainly human-caused. A 2021 study of over 88,000 climate-related papers (2012–2020) found greater than 99% consensus (only a tiny handful of skeptical papers). Earlier work (e.g., ~97% for 1991–2012) has strengthened over time.[2]

•Surveys of climate scientists and statements from major scientific bodies (NASA, NOAA, AAAS, National Academies of Sciences, American Chemical Society, and many others worldwide) affirm this position.[3]

•NASA states that human activities are driving the global warming trend observed since the mid-20th century and that “human activity is the principal cause.”[4]

Key Evidence

•Greenhouse gas increases: Atmospheric CO₂, methane, and nitrous oxide have risen sharply due to human activities (burning fossil fuels, deforestation, agriculture, industry). Concentrations are unprecedented in at least 800,000 years. Isotopic fingerprints confirm the CO₂ comes primarily from fossil fuels, not natural sources.[4]

•Basic physics and the greenhouse effect: These gases trap heat. The natural greenhouse effect makes Earth habitable; human enhancement is warming it further.

•Climate models and attribution: Models that include only natural factors (solar output, volcanoes) cannot reproduce the observed warming. Models that include human greenhouse gas emissions and other anthropogenic forcings match observations closely. “Fingerprinting” studies identify human patterns in the data (e.g., tropospheric warming + stratospheric cooling, which matches greenhouse gases rather than solar changes).[5]

•Rate and paleoclimate context: The current rate of warming is much faster than natural changes in recent millennia (e.g., post-ice age recoveries). Paleoclimate records (ice cores, tree rings, etc.) show no comparable natural driver matching the recent trend.[6]

•Multiple independent lines: Observed changes include rising global temperatures, ocean heat content and acidification, sea-level rise, shrinking ice sheets/glaciers/sea ice, and shifts in extremes. These align with human influence across atmosphere, ocean, cryosphere, and biosphere.[1]

Natural factors continue to influence short-term variability (e.g., El Niño, volcanic eruptions, solar cycles), but they do not explain the long-term warming trend of the past ~150 years, especially the accelerated warming since the mid-20th century. Solar output has been stable or slightly declining while temperatures rose.[4]

This conclusion has strengthened progressively across IPCC reports (from “discernible human influence” in 1995 to “unequivocal” today) as data, observations, and models improved.[7] Leading scientific organizations treat it as established fact based on evidence, not opinion. While climate has always varied naturally over Earth’s history, the current rapid change is anthropogenic.

Citations (7)

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.”
2climateattribution.orgAcademic
https://climateattribution.org/resources/greater-than-99-consensus-on-human-caused-climate-change-in-the-peer-reviewed-scientific-literature/
Backs: “Earlier work (e.g., ~97% for 1991–2012) has strengthened over time.”
3nasa.govGovernment
https://science.nasa.gov/climate-change/scientific-consensus/
Backs: “Surveys of climate scientists and statements from major scientific bodies (NASA, NOAA, AAAS, National Academies of Sciences, American Chemical Society, and many others worldwide) affirm this position.”
4nasa.govGovernment
https://science.nasa.gov/climate-change/causes/
Backs: “NASA states that human activities are driving the global warming trend observed since the mid-20th century and that “human activity is the principal cause.””
5ipcc.chGovernment
https://www.ipcc.ch/report/ar6/wg1/downloads/faqs/IPCC_AR6_WGI_FAQ_Chapter_03.pdf
Backs: ““Fingerprinting” studies identify human patterns in the data (e.g., tropospheric warming + stratospheric cooling, which matches greenhouse gases rather than solar changes).”
6nasa.govGovernment
https://science.nasa.gov/climate-change/evidence/
Backs: “Paleoclimate records (ice cores, tree rings, etc.) show no comparable natural driver matching the recent trend.”
7thebulletin.orgNews and mediaquality 0.82
https://thebulletin.org/2025/11/a-climate-scientist-reflects-on-30-years-fighting-the-forces-of-unreason/
Backs: “This conclusion has strengthened progressively across IPCC reports (from “discernible human influence” in 1995 to “unequivocal” today) as data, observations, and models improved.”