Carbon Dioxide Measurements

This site provides access to products from the Scripps CO2 Program and serves as a tribute to its founder Charles David Keeling

The primary (in situ) record from Mauna Loa Observatory, Hawaii is based on measurements made with an analyzer at the site. At all other sampling stations, the records are based on flask samples returned to our La Jolla laboratory for analysis. Flasks have also been redundantly collected at Mauna Loa. Isotopic measurements on flask samples of the 13C/12C and 18O/16O ratios of CO2, which we began in 1978, have gradually been expanded to include all stations where we measure the CO2 concentration.

CO2 Concentration at Mauna Loa Observatory, Hawaii

The Scripps CO2 program was initiated in 1956 by Charles David Keeling and operated under his direction until his passing in 2005. It is currently being continued by Ralph F. Keeling, who also runs a parallel program at SIO to measure changes in atmospheric O2 and Ar abundances (Scripps O2 Program).

Current results, including data sets and graphics, are available here from the ongoing program to measure CO2 and chemical species.

For daily updates of the CO2 Concentration at Mauna Loa Obervatory, Hawaii, see


Measurements by the Scripps CO2 program are supported by the U.S. Department of Energy (DOE) and by Earth Networks, a technology company that is collaborating with Scripps to expand the global GHG monitoring network.

In kind support for field operations is also provided by the National Oceanographic and Atmospheric Administration (NOAA), the National Science Foundation (NSF), Environment Canada, and the New Zealand National Institute for Water and Atmospheric Research (NIWA).