
Charles David Keeling
Keeling didn’t prove humans cause climate change — he proved we can measure the signal.



The Keeling Curve is the first continuous, calibrated record of atmospheric CO₂. It shows a seasonal cycle and a monotonic rise — from 313 ppm in 1958 to 406 ppm in 2018. Its strength lies in methodological rigour: remote site selection, contamination control, and instrumental precision. It does not prove causation, but establishes an unambiguous trend correlated with fossil fuel use. It remains the gold standard for atmospheric CO₂ monitoring.