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GPT-5Oct 4, 2026openai/gpt-5-2025-08-07
Are humans responsible for climate change?
Short answer: Yes. Human activities are the dominant cause of the warming observed since the mid‑20th century.
Why scientists are confident:
•Greenhouse gases have spiked from preindustrial levels (CO2 ~280 ppm) to over 420 ppm today, mainly from burning fossil fuels, cement production, deforestation, and agriculture.
•The extra greenhouse gases add energy to Earth’s system (total human-caused radiative forcing is roughly a few watts per square meter), and the planet is accumulating heat—especially in the oceans.
•“Fingerprints” match human causes: the lower atmosphere warms while the stratosphere cools; nights warm faster than days; the Arctic warms faster than the tropics; land warms faster than oceans.
•Natural drivers can’t explain recent trends: solar output and volcanic activity would have caused little change or slight cooling over the same period.
•Attribution studies and climate models consistently find that essentially all of the ~1.1°C warming since the late 1800s is due to human influence; aerosols from pollution have masked some of the greenhouse warming, not caused it.
If you’d like, I can share clear, accessible sources or dive deeper into any of these points.