NOTICE (September 2017): Data previously stored at the CDIAC archive are being transitioned to the new, ESS-DIVE archive. This website provides access to the CDIAC data during the transition. If you have any questions regarding the new archive or the data transition, please contact

image image image image

Atmospheric CO2 Records from Sites in the Main Geophysical Observatory Air Sampling Network

Main Geophysical Observatory monitoring sites

Map showing location of the Main Geophysical Observatory air sampling network sites