Born in 1979

337 ppmin 1979, annual mean

427 ppmin 2025, annual mean

27% more CO2 in the air

In 1979 the air held 336.84 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: 27% more CO2 in the air. Figures from the data files retrieved 16 October 2026.

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Another year · CO2 in the air today

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