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GPT-5Oct 25, 2026openai/gpt-5-2025-08-07
Is climate change real?
Yes. The Earth is warming and humans are the primary cause.
Why scientists are confident:
•Physics: Greenhouse gases like CO2 trap heat; this has been understood since the 1800s.
•Measurements: The planet’s average surface temperature has risen by about 1.2°C (2.2°F) since the late 1800s.
•Greenhouse gases: CO2 has climbed from ~280 ppm preindustrial to over 420 ppm today, with isotope “fingerprints” showing most of the rise comes from fossil fuels.
•Oceans and ice: Over 90% of the excess heat is going into the oceans; glaciers are shrinking; Greenland and Antarctica are losing ice; sea level has risen by about 8–9 inches since 1880, and the rate is accelerating.
•Weather and ecosystems: Heatwaves are more frequent and intense, heavy rainfall events are increasing, growing seasons are shifting, and species ranges are moving.
Uncertainties remain about the exact pace and local details, but the direction and main cause are well established. If you’d like, I can share sources or dig into any piece of evidence.