Climate · CO₂
The carbon spiral
Atmospheric CO₂ wound month by month: the seasonal swing (the breathing of Northern Hemisphere vegetation) rides on a steady rise since 1958.
- Year
- —
- CO₂
- —
CO₂, latest month
426.1 ppm
Deseasonalised trend
429.6 ppm
Above 280 ppm
52 %
Mauna Loa monthly mean CO₂ (NOAA GML) · U.S. Government work, public domain; cite Lan, X., Tans, P. & Thoning, K. W., NOAA GML · 10/23/26
Radius proportional to the NOAA GML monthly concentration; one turn per year.
Latest month
426.07 ± 0.23 ppm
2026-09
Mauna Loa monthly mean CO₂ (NOAA GML) · U.S. Government work, public domain; cite Lan, X., Tans, P. & Thoning, K. W., NOAA GML · 10/23/26
Latest deseasonalized month
429.55 ppm
2026-09
seasonal cycle removed by NOAA
Mauna Loa monthly mean CO₂ (NOAA GML) · U.S. Government work, public domain; cite Lan, X., Tans, P. & Thoning, K. W., NOAA GML · 10/23/26
Lowest value of the series
312.42 ppm
1958-10
Mauna Loa monthly mean CO₂ (NOAA GML) · U.S. Government work, public domain; cite Lan, X., Tans, P. & Thoning, K. W., NOAA GML · 10/23/26
Highest value of the series
432.34 ± 0.28 ppm
2026-05
Mauna Loa monthly mean CO₂ (NOAA GML) · U.S. Government work, public domain; cite Lan, X., Tans, P. & Thoning, K. W., NOAA GML · 10/23/26
Atmospheric CO₂ at Mauna Loa since 1958
Mauna Loa monthly mean CO₂ (NOAA GML) · U.S. Government work, public domain; cite Lan, X., Tans, P. & Thoning, K. W., NOAA GML · 10/23/26
Mauna Loa monthly mean CO₂ (NOAA GML) · U.S. Government work, public domain; cite Lan, X., Tans, P. & Thoning, K. W., NOAA GML · 10/23/26
Show the data as a table
Last five years
Mauna Loa monthly mean CO₂ (NOAA GML) · U.S. Government work, public domain; cite Lan, X., Tans, P. & Thoning, K. W., NOAA GML · 10/23/26
Show the data as a table
Method and sources
Continuous NOAA GML measurements at Mauna Loa Observatory (Hawaii), monthly means and deseasonalized series published by NOAA (Thoning et al., 1989). After the 2022 eruption, measurements moved to Maunakea and were reconciled by NOAA; the series is taken as distributed.
Missing values (-99.99) are ignored; the uncertainty of the monthly mean is imported when provided.
Reading these data
Mauna Loa is a background site representative of the northern hemisphere; the global mean differs slightly. The latest months are preliminary.
SOURCES OF THIS PAGE
- Mauna Loa monthly mean CO₂ (NOAA GML)
-
Lan, X., Tans, P., & Thoning, K. W. (2026). Trends in globally-averaged CO₂ determined from NOAA Global Monitoring Laboratory measurements; Mauna Loa monthly mean, after Thoning et al. (1989).
· doi:10.1029/JD094iD06p08549 · source page ↗
Licence : U.S. Government work, public domain; cite Lan, X., Tans, P. & Thoning, K. W., NOAA GML · retrieved on Oct 23, 2026 · SHA-256 d895fb5b4a59… - Thoning et al. (1989)
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Thoning, K. W., Tans, P. P., & Komhyr, W. D. (1989). Atmospheric carbon dioxide at Mauna Loa Observatory: 2. Analysis of the NOAA GMCC data, 1974–1985. Journal of Geophysical Research, 94(D6), 8549–8565.
· doi:10.1029/JD094iD06p08549
Licence : Published literature; cited