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GPT-5Nov 1, 2026openai/gpt-5-2025-08-07
Are humans responsible for climate change?
Yes. Humans are the primary cause of the recent, rapid climate change.
What’s driving it
•Greenhouse gases from burning coal, oil, and gas, plus deforestation and some industrial/agricultural practices (CO2, methane, nitrous oxide).
•These gases increase Earth’s heat trap (radiative forcing), warming the surface and oceans.
How we know
•Fingerprints: the lower atmosphere warms while the stratosphere cools; nights and winters warm faster than days and summers; the Arctic warms fastest; oceans store over 90% of the added heat.
•Fossil-fuel “signature”: the carbon isotope mix in the air matches fossil fuels, and atmospheric oxygen is declining as combustion uses it.
•Sun/volcano checks: solar output changes are too small and would warm the stratosphere (it’s cooling instead); big volcanoes mostly cause short-term cooling.
•Models: 20th–21st century warming is reproduced only when human emissions are included; natural factors alone can’t explain the trend.
How much
•Best estimates attribute essentially all of the observed global warming since the mid-1900s to human activity; natural factors would have produced little to no net warming over this period.