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GPT-5Nov 7, 2026openai/gpt-5-2025-08-07
Are humans responsible for climate change?
Yes. It’s unequivocal that recent global warming is driven by human activities, primarily the burning of fossil fuels, deforestation, and some industrial/agricultural practices that increase heat‑trapping gases (CO2, methane, nitrous oxide).
Why scientists are confident:
•Physics: Greenhouse gases absorb and re‑emit infrared radiation; this has been measured in the lab for over a century.
•Fingerprints: The lower atmosphere warms while the stratosphere cools; nights and winters warm faster than days and summers; land warms faster than oceans—patterns expected from greenhouse gases, not from the Sun.
•Isotopes and oxygen: The carbon added to the air has the isotopic “signature” of fossil fuels, and atmospheric oxygen is declining as those fuels burn.
•Energy balance: Satellites detect less heat escaping to space at the exact wavelengths absorbed by CO2 and other greenhouse gases.
•Models and attribution studies: Climate models only reproduce the observed warming trend when human emissions are included; natural factors alone would not have produced the modern increase.
Natural variability still affects year‑to‑year weather and regional patterns, but the long‑term warming trend since the mid‑20th century is overwhelmingly human‑caused. If you’d like, I can point you to concise summaries from the IPCC or the U.S. National Climate Assessment.