One chemist's daily readings became climate science's most famous graph

Starting in 1958, Charles David Keeling began precisely measuring atmospheric CO2 from Mauna Loa Observatory in Hawaii. The resulting graph, the Keeling Curve, zigzags with the seasons as plants breathe, while climbing relentlessly year after year, the longest continuous record of humanity's changing atmosphere.

— Charles David Keeling, The Keeling Curve — Scripps Institution of Oceanography, begun 1958