Usage restrictions

Scripps CO2 program graphics on are licensed under a CC BY license, Creative Commons Attribution 4.0 International License (, which clarifies appropriate uses and requirements.  The graphics must be credited to the Scripps Institution of Oceanography at UC San Diego.  For graphics which show ice-core data, additional credit must be given for these products, as appropriate for that source (see below).

For applications supporting peer-reviewed scientific publications, ethical usage may also require disclosing intentions at early stages to avoid duplicating ongoing studies at Scripps or elsewhere. For such applications, coauthorship may sometimes be appropriate. An example would be if an important result or conclusion depends on this product, such as the first account of a previously unreported phenomenon.

The graphics referred to here are the plots displayed on the front page and located at PDF Downloads.

Please direct queries to Ralph Keeling (

MLO data from the most recent month is preliminary

Mauna Loa carbon dioxide data from the most recent month is preliminary and subject to subsequence updates to account for retrospective calibration and quality control. See for data that has passed these routine quality checks and updates. The datasets are archived once a month on the website and the Scripps CO2 Program library archive database at UCSD.

Data sources

CO2 data starting in 1958 are from the Scripps CO2 program



Citation: 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.

CO2 data before 1958 going back 2000 years



Citation: Rubino, Mauro; Etheridge, David; Thornton, David; Allison, Colin; Francey, Roger; Langenfelds, Ray; Steele, Paul; Trudinger, Cathy; Spencer, Darren; Curran, Mark; Van Ommen, Tas; Smith, Andrew (2019): Law Dome Ice Core 2000-Year CO2, CH4, N2O and d13C-CO2. v1. CSIRO. Data Collection.


CO2 data before 1958 going back 800,000 years



Citation: Lüthi, D., M. Le Floch, B. Bereiter, T. Blunier, J.-M. Barnola, U. Siegenthaler, D. Raynaud, J. Jouzel, H. Fischer, K. Kawamura, and T.F. Stocker. 2008. High-resolution carbon dioxide concentration record 650,000-800,000 years before present. Nature, Vol. 453, pp. 379-382, 15 May 2008.