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GPT-5Sep 29, 2026openai/gpt-5-2025-08-07
Are humans responsible for climate change?
Yes. The warming observed since the mid‑20th century is overwhelmingly due to human activities.
Why scientists are confident:
•Greenhouse gases from burning fossil fuels, deforestation, and agriculture have raised CO2 by about 50% above preindustrial levels, strengthening the greenhouse effect.
•The “fingerprints” match human causes: the lower atmosphere warms while the stratosphere cools; nights warm faster than days; the Arctic warms fastest; oceans store most excess heat.
•Isotope evidence shows the extra CO2 comes from ancient carbon (fossil fuels), alongside a measured decline in atmospheric oxygen consistent with combustion.
•Energy-balance studies and climate models reproduce the observed warming only when human emissions are included; natural drivers (solar cycles, volcanoes) can’t explain the magnitude or pattern.
•Aerosols from pollution have partially masked warming; accounting for them, human influence explains essentially all of the net warming since 1950.
If you’d like, I can point you to the latest IPCC and U.S. National Climate Assessment summaries.