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Atmospheric Carbon Dioxide
CO₂ concentration at Mauna Loa Observatory, parts per million
Plays the chart through its history. Pauses are where the data set a record or moved most.
Monthly average · Continuation · the recent trend, flattening · 30 days
Seasonally adjusted trend · Continuation · the recent trend, flattening · 30 days
Dashed: the projection from the latest reading. Shaded: the range about two in three outcomes land in. A projection, not a promise.
From NOAA Global Monitoring Laboratory. The yearly wave is the Northern Hemisphere growing season.
The longest direct record of carbon dioxide in the atmosphere, begun in 1958. The sawtooth is seasonal; the trend has risen every year.
What this chart reads
- Atmospheric CO₂ at Mauna Loa (Monthly Average)as “Monthly average”latest 2026-09-01
- Atmospheric CO₂ at Mauna Loa (De-seasonalized Trend)as “Seasonally adjusted trend”latest 2026-09-01
Sources
Atmospheric CO₂ at Mauna Loa (Monthly Average). Source: NOAA Global Monitoring Laboratory, Trends in Atmospheric Carbon Dioxide (co2_mm_mlo.csv), https://gml.noaa.gov/ccgg/trends/. Data from March 1958 to April 1974 were obtained by C. David Keeling of the Scripps Institution of Oceanography. Cite: Dr. Xin Lan, NOAA/GML (gml.noaa.gov/ccgg/trends/) and Dr. Ralph Keeling, Scripps Institution of Oceanography (scrippsco2.ucsd.edu/). US federal data, public domain; NOAA asks that GML receive credit.
Atmospheric CO₂ at Mauna Loa (De-seasonalized Trend). Source: NOAA Global Monitoring Laboratory, Trends in Atmospheric Carbon Dioxide (co2_mm_mlo.csv, "deseasonalized" column), https://gml.noaa.gov/ccgg/trends/. Data from March 1958 to April 1974 were obtained by C. David Keeling of the Scripps Institution of Oceanography. Cite: Dr. Xin Lan, NOAA/GML and Dr. Ralph Keeling, Scripps Institution of Oceanography. US federal data, public domain.
Charts are drawn from Palanor's signal library and recomputed from source data on every view. Transformations (changes, indexing, year-on-year rates) are Palanor's.