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GPT-5Oct 14, 2026openai/gpt-5-2025-08-07
Are humans responsible for climate change?
Yes. The overwhelming scientific evidence shows humans are the primary cause of recent global warming.
What’s driving it
•Greenhouse gases from burning coal, oil, and gas, plus deforestation, cement, agriculture (methane and nitrous oxide).
•Atmospheric CO2 has risen from ~280 ppm pre‑industrial to over 420 ppm today—mostly from fossil fuels.
How we know
•Physics: more greenhouse gases trap more outgoing heat; satellites measure increased downwelling longwave radiation.
•Fingerprints: the lower atmosphere warms while the stratosphere cools; nights warm faster than days; the Arctic warms faster than the globe; the ocean stores most of the excess heat.
•Attribution studies: climate models match observed warming only when human emissions are included; natural factors alone (solar/volcanoes) can’t explain it.
•Isotopes: the carbon added to the air bears the fossil‑fuel signature.
How much
•Humans have caused roughly 1.1–1.3°C of global average warming since 1850–1900, accounting for essentially all of the net warming since the mid‑20th century; natural variability mainly affects short‑term and regional ups and downs.
If you’d like, I can share key sources or dig into any of these lines of evidence in more detail.