Are humans responsible for climate change?

Yes

Yes, humans are the primary cause of recent climate change (global warming since the Industrial Revolution). This is the overwhelming scientific consensus, described as "unequivocal" by the Intergovernmental Panel on Climate Change (IPCC).[1]

Scientific Consensus

•Multiple independent analyses of peer-reviewed literature show extremely high agreement: a 2021 study of over 88,000 climate-related papers found greater than 99.9% consensus that climate change is mainly human-caused (updating earlier ~97% figures from studies covering 1991–2012).[2]

•Surveys of climate scientists and statements from major scientific organizations (NASA, NOAA, AAAS, Royal Society, National Academies, and others worldwide) affirm that human activities are the dominant driver.[3]

•The IPCC’s Sixth Assessment Report (AR6, 2021) and Synthesis Report (2023) state it is unequivocal that human influence has warmed the atmosphere, ocean, and land. The likely range of human-caused global surface temperature increase from 1850–1900 to 2010–2019 is 0.8–1.3°C (best estimate 1.07°C), matching the observed warming of about 1.1°C. Natural drivers contributed negligibly (roughly –0.1 to +0.1°C).[4]

Key Evidence

Several independent lines of evidence support this:

1.Greenhouse gas increases from human activities: Atmospheric CO₂ has risen ~47–50% since 1750 (from ~280 ppm to over 410–420 ppm), primarily from burning fossil fuels (coal, oil, gas), cement production, and land-use changes like deforestation. Methane and nitrous oxide have also increased significantly. Isotopic “fingerprints” (e.g., declining ¹³C/¹²C ratios and atmospheric oxygen levels) confirm the extra CO₂ comes mainly from fossil fuels, not natural sources like volcanoes or the ocean.[5]

2.Basic physics and radiative forcing: Greenhouse gases trap heat. Human-caused radiative forcing is strongly positive and has increased. Observations show the expected patterns: warming in the lower atmosphere (troposphere) and cooling in the upper atmosphere (stratosphere), inconsistent with solar or other natural forcings alone.[5]

3.Climate models and attribution studies: Models that include only natural factors (solar variability, volcanoes, internal variability like El Niño) cannot reproduce the observed warming trend since the mid-20th century—they often show slight cooling or much less warming. Models including human greenhouse gas emissions and aerosols match observations closely. “Fingerprinting” techniques attribute the bulk of warming, ocean heat content rise, sea-level rise, ice loss, and many extreme events to human influence.[6]

4.Rate and uniqueness of change: The current rate of warming is unprecedented in at least the last 2,000 years (and likely much longer) based on paleoclimate records (ice cores, tree rings, etc.). CO₂ levels are higher than at any point in at least the last 800,000 years.[7]

5.Observed impacts matching predictions: Rising global temperatures, ocean warming and acidification, shrinking glaciers and ice sheets, sea-level rise (~21–24 cm since 1880, accelerating), shifts in species ranges, and increased frequency/intensity of heatwaves and other extremes align with human-driven forcing.[8]

Natural climate variability and forcings (solar cycles, volcanic eruptions, orbital changes) have always existed and continue to play roles on shorter timescales or regionally, but they do not explain the long-term global warming trend of the past ~150 years. In fact, some natural factors have exerted a slight cooling influence recently.

This conclusion is based on decades of accumulating evidence from observations, physics, paleoclimate data, and modeling, assessed by thousands of scientists through processes like the IPCC. While uncertainties remain in exact future projections, regional details, or feedback strengths, the core attribution of recent warming to human activities is robust and has strengthened over time.

Citations (8)

1climate.govGovernment
https://www.climate.gov/news-features/climate-qa/isnt-there-lot-disagreement-among-climate-scientists-about-global-warming
Backs: “This is the overwhelming scientific consensus, described as "unequivocal" by the Intergovernmental Panel on Climate Change (IPCC).”
attribution, article, points to yes. Claim: IPCC describes human influence on climate as unequivocal; overwhelming scientific consensus that humans are the primary cause of recent warming.
2eurekalert.orgAcademic
https://www.eurekalert.org/news-releases/931811
Backs: “Multiple independent analyses of peer-reviewed literature show extremely high agreement: a 2021 study of over 88,000 climate-related papers found greater than 99.9% consensus that climate change is mainly human-caused (updating earlier ~97% figures from studies covering 1991–2012).”
statistic, article, points to yes. Claim: A 2021 study of over 88,000 climate papers found greater than 99.9% consensus that climate change is mainly human-caused.
3nasa.govGovernment
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, Royal Society, National Academies, and others worldwide) affirm that human activities are the dominant driver.”
evidence, article, points to yes. Claim: Surveys of scientists and major scientific organizations affirm human activities are the dominant driver of warming.
4ipcc.chGovernment
https://www.ipcc.ch/report/ar6/wg1/chapter/chapter-1/
Backs: “Natural drivers contributed negligibly (roughly –0.1 to +0.1°C).”
statistic, official document, points to yes. Claim: IPCC AR6 attributes 0.8–1.3°C of warming to humans, best estimate 1.07°C, with natural drivers contributing negligibly.
5royalsociety.orgAcademic
https://royalsociety.org/news-resources/projects/climate-change-evidence-causes/
Backs: “Isotopic “fingerprints” (e.g., declining ¹³C/¹²C ratios and atmospheric oxygen levels) confirm the extra CO₂ comes mainly from fossil fuels, not natural sources like volcanoes or the ocean.”
evidence, article, points to yes. Claim: CO₂ rise since 1750 comes mainly from fossil fuels, confirmed by isotopic fingerprints; observed warming troposphere and cooling stratosphere inconsistent with natural forcings.
6ipcc.chGovernment
https://www.ipcc.ch/report/ar6/wg1/chapter/chapter-3
Backs: ““Fingerprinting” techniques attribute the bulk of warming, ocean heat content rise, sea-level rise, ice loss, and many extreme events to human influence.”
evidence, official document, points to yes. Claim: Natural-only models cannot reproduce observed warming; fingerprinting attributes warming, ocean heat, sea-level rise, ice loss and extremes to human influence.
7news.google.comNews and mediaquality 0.79
https://news.google.com/rss/articles/CBMibkFVX3lxTE5RamFDX1dfZVdaeHZrY2xURC1ZMUxCVlZBbUhzQzJ0VjVVdjdZTVg4bHVsaE9XeEM1Y09sWl9aT2k1b0ZicXljaWI4SkVIckpaMlNwelhfcUJ4UjAwR015ODVMVXV2SGdZZkN1b0dR?oc=5
Backs: “CO₂ levels are higher than at any point in at least the last 800,000 years.”
evidence, other, points to yes. Claim: Current warming rate is unprecedented in at least 2,000 years and CO₂ is higher than in at least 800,000 years.
8climate.govGovernment
https://www.climate.gov/news-features/climate-qa/what-evidence-exists-earth-warming-and-humans-are-main-cause
Backs: “Rising global temperatures, ocean warming and acidification, shrinking glaciers and ice sheets, sea-level rise (~21–24 cm since 1880, accelerating), shifts in species ranges, and increased frequency/intensity of heatwaves and other extremes align with human-driven forcing.”
evidence, article, points to yes. Claim: Observed impacts like ocean warming, shrinking ice, sea-level rise of about 21–24 cm and extreme heat align with human-driven forcing.