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GPT-5Sep 10, 2026openai/gpt-5-2025-08-07
Are humans responsible for climate change?
Yes
Yes. The evidence shows humans are the dominant cause of the warming observed since the mid‑20th century.
Why scientists are confident:
•Greenhouse gases: Burning fossil fuels, deforestation, and agriculture raise CO2, methane, and nitrous oxide, strengthening the greenhouse effect.
•Clear fingerprints:
•CO2 from fossil fuels has a distinct isotopic signature (lower 13C/12C); atmospheric O2 is declining as carbon is burned.
•The troposphere warms while the stratosphere cools—expected from greenhouse gases, not from a brighter Sun.
•Nights and winters warm faster than days and summers; the Arctic warms faster than the globe; the oceans are accumulating heat.
•Natural causes don’t match the pattern:
•Solar output has been flat or slightly down while temperatures rose.
•Volcanoes mostly cause short‑term cooling; they emit far less CO2 than humans.
•Internal variability (e.g., El Niño/La Niña) adds ups and downs but can’t produce the sustained global trend.
•Quantified attribution: The IPCC (AR6) finds human activities caused about 1.07°C of warming in 2010–2019 relative to 1850–1900—essentially all of the observed warming—while natural factors contributed little or slightly cooled.
•Scientific consensus: National academies worldwide and about 97–99% of actively publishing climate scientists agree the recent warming is primarily human‑caused.
In short, humans are responsible for essentially all of the recent climate change.