Scientists at the Scripps Institution of Oceanography measured a record level of carbon dioxide in the atmosphere: 420 parts per million, in 2021. This daily record, the Keeling Curve, is considered the foundation of modern climate change research.
Geochemist Charles David Keeling joined Scripps in 1956 and built a manometer and other equipment to isolate the carbon dioxide in air samples. In 1958, the average carbon dioxide concentration of the first measurement was 316.16 parts per million. In 2013, the CO2 concentration surpassed 400 ppm for the first time in human history.