Scripps CO2 program grants unrestricted usage of the figures on this website provided credit is given to the Scripps Institution of Oceanography. For figures showing data before 1958, permission may also be required from those providing these earlier data (see links below). The figures referred to here are the plots displayed on the front page and located at PDF Downloads.
CO2 data after 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. http://escholarship.org/uc/item/09v319r9
CO2 data before 1958 going back 2000 years
Citation: MacFarling Meure, C., D. Etheridge, C. Trudinger, P. Steele, R. Langenfelds, T. van Ommen, A. Smith, and J. Elkins. 2006. The Law Dome CO2, CH4 and N2O Ice Core Records Extended to 2000 years BP. Geophysical Research Letters, Vol. 33, No. 14, L14810 10.1029/2006GL026152.
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.
Future CO2 levels will be strongly dependent on future CO2 emissions. The three scenarios are based on different assumptions for future emissions. The scenarios use the Joos et al (2013) impulse-response model to account for land and ocean carbon sinks. The model is forced with past fossil-fuel and land-use emissions from CDIAC and future CO2 emissions as shown. Future emissions either use RCP emission scenarios (e.g. Fuss et al., 2014) or use emissions based on a back calculation, as required to keep CO2 constant at current levels. The model starts at the observed preindustrial level of 282 ppm and is calibrated to match the latest CO2 observations by uniformly adjusting the global sink strength, which requires a ~19% increase in sink strength.
References and data sources
Fuss et al., “Betting on negative emissions.” Nature Climate Change 4: 850.
Joos et al. (2013). “Carbon dioxide and climate impulse response functions for the computation of greenhouse gas metrics: a multi-model analysis.” Atmospheric Chemistry and Physics 13(5): 2793-2825.
For an overview of RCP pathways, see: van Vuuren et al. (2011) Climatic Change, 109: 5. https://doi.org/10.1007/s10584-011-0148-z
Carbon Flux to the Atmosphere from Land-Use Changes 1850-2005 Data
Global Carbon Emissions Data