Born in 1971
326 ppmin 1971, annual mean
427 ppmin 2025, annual mean
31% more CO2 in the air
In 1971 the air held 326.32 parts per million of CO2, the annual mean measured at Mauna Loa.
In 2025, the latest complete year, the annual mean at Mauna Loa was 427.35 ppm: 31% more CO2 in the air. Figures from the data files retrieved 16 October 2026.
Sources
- Annual mean CO2, Mauna Loa Observatory, Hawaii. Dr. Xin Lan, NOAA/GML (gml.noaa.gov/ccgg/trends/) and Dr. Ralph Keeling, Scripps Institution of Oceanography (scrippsco2.ucsd.edu/). Retrieved 16 October 2026. Terms.
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