Born in 1932
308 ppmin 1932, ice-core estimate
427 ppmin 2025, annual mean
39% more CO2 in the air
In 1932 the air held 308.28 parts per million of CO2, an estimate from Antarctic ice cores (Bereiter et al. 2015), interpolated between the samples either side of the middle of that year.
In 2025, the latest complete year, the annual mean at Mauna Loa was 427.35 ppm: 39% more CO2 in the air. Figures from the data files retrieved 16 October 2026.
Sources
- Antarctic Ice Cores Revised 800KYr CO2 Data (Bereiter et al. 2015 composite): age and CO2. Bereiter, B.; Eggleston, S.; Schmitt, J.; Nehrbass-Ahles, C.; Stocker, T.F.; Fischer, H.; Kipfstuhl, S.; Chappellaz, J.A. (2015-02-04): NOAA/WDS Paleoclimatology - Antarctic Ice Cores Revised 800KYr CO2 Data. NOAA National Centers for Environmental Information. https://doi.org/10.25921/n8y4-bp27. Accessed 2026-10-15. Publication: Bereiter, B. et al. (2015), Revision of the EPICA Dome C CO2 record from 800 to 600 kyr before present, Geophysical Research Letters, https://doi.org/10.1002/2014GL061957. Retrieved 15 October 2026. Terms. Trimmed from the published file.
- 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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