Scripps Institution of Oceanography, UC San Diego (Scripps CO2 Program)
Scripps CO2 Program atmospheric CO2 and carbon-13 records at Mauna Loa
The original Keeling Curve programme. Monthly mean CO2 from continuous in situ measurements at Mauna Loa Observatory, Hawaii, from March 1958, on the 2012 SIO manometric mole fraction scale, and the monthly carbon-13 to carbon-12 ratio (delta-13C, per mil) of CO2 in flask samples from February 1980. The falling delta-13C is the isotopic signature of carbon from fossil fuels and plants. Measured independently of NOAA's Mauna Loa record. Months from December 2022 to February 2023 were measured on nearby Maunakea after the 2022 Mauna Loa eruption, as the file's station column records. Missing values are -99.99. The vintage is the archive date in each file's header.
Numbers published from it
None yet: this source is registered and its licence checked, and its numbers are being prepared.
Licence and credit
- Licence
- CC BY 4.0
- What the terms say
“data and graphics on scrippsco2.ucsd.edu are licensed under a CC BY license, Creative Commons Attribution 4.0 International License (creativecommons.org/licenses/by/4.0/), which clarifies appropriate uses and requirements, including that credit be given to the Scripps Institution of Oceanography at UC San Diego.”
From the producer's terms, checked 2026-10-04; re-checked automatically every week.
- Credit we give
- Scripps CO2 Program, Scripps Institution of Oceanography at UC San Diego (R. F. Keeling, S. J. Walker, S. C. Piper and A. F. Bollenbacher), data archive dated {version}. CC BY 4.0.
- Copy of the raw file
- Allowed: we keep a public copy of every version we use.
- Cite as
- C. D. Keeling, S. C. Piper, R. B. Bacastow, M. Wahlen, T. P. Whorf, M. Heimann, and H. A. Meijer, Exchanges of atmospheric CO2 and 13CO2 with the terrestrial biosphere and oceans from 1978 to 2000. I. Global aspects, SIO Reference Series, No. 01-06, Scripps Institution of Oceanography, San Diego, 88 pages, 2001.
Files
Monthly mean in situ CO2 at Mauna Loa from March 1958 (ppm): raw, seasonally adjusted, spline fit and filled columns, plus a station code (MLO or MKO). A quoted text header block precedes the data; missing = -99.99.
https://keelinglabsites.ucsd.edu/websitedataco2/monthly_in_situ_co2_mlo.csvMonthly mean delta-13C of CO2 in Mauna Loa flask samples from February 1980 (per mil, Scripps isotope scale). A quoted text header block precedes the data; missing = -99.99.
https://keelinglabsites.ucsd.edu/websitedataco2/monthly_flask_c13_mlo.csv
Status
- Programme
- In situ file updated in September 2026 (data through 19 September 2026); the flask delta-13C file still carries the archive of 6 June 2025 (data through December 2024). The programme is privately funded: "Scripps CO2 measurements at Mauna Loa are currently supported by Schmidt Sciences with supplemental support from Earth Networks" (keelingcurve.ucsd.edu, 2026-10-04). It samples at NOAA's Mauna Loa Observatory, which the FY2026 and FY2027 US budget requests proposed closing with the rest of NOAA's research labs.
- Updates
- In situ file monthly or more often; flask isotope file roughly yearly, about a year behind
- Last check
- Unchanged since the last fetch (2026-10-05T11:04:40Z)
- Independent sources measuring the same thing
- Trends in atmospheric carbon dioxide