Keeling Begins Continuous Atmospheric CO2 Measurement at Mauna Loa
March 29, 1958 · 20th Century
On March 29, 1958, Charles David Keeling of the Scripps Institution of Oceanography recorded the first continuous atmospheric CO2 measurement at the Mauna Loa Observatory in Hawaii, registering 313 parts per million. The resulting dataset — the Keeling Curve — became the longest uninterrupted instrumental record of atmospheric CO2. Within one year the data showed a rising trend attributed to fossil fuel combustion. The curve revealed both seasonal variation driven by photosynthesis and a consistent annual increase in greenhouse gas concentrations, providing the empirical foundation for modern climate science.
Key Figures
Charles David Keeling
Locations
Mauna Loa Observatory
Topics
scienceclimateclimate changemeasurementgreenhouse gasatmospheric CO2
Connected Events — 7 Connections
Industrial chemistry that drove CO2 rise Keeling was measuring Haber and Bosch Develop Synthetic Nitrogen Fixation
Keeling Curve quantified the anthropogenic signal that dwarfs volcanic forcing like Tambora Mount Tambora Eruption Causes the Year Without a Summer
The Keeling Curve dataset captured Pinatubo's temporary cooling signature Mount Pinatubo Eruption Cools Global Climate
Keeling's CO2 data helped distinguish anthropogenic warming from natural orbital forcing described by Milankovitch Milankovitch Publishes Orbital Climate Theory
Pinatubo's cooling signature was captured by the Keeling Curve CO2 monitoring dataset Mount Pinatubo Eruption Cools Global Climate
Keeling's measurements confirmed the CO2 accumulation Arrhenius predicted would cause warming Arrhenius Calculates CO2-Driven Warming
The rising CO₂ levels Keeling began measuring in 1958 result partly from burning Carboniferous coal — releasing carbon these forests sequestered 305 million years ago Carboniferous Rainforest Collapse
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