Due to the eruption of the Mauna Loa Volcano, measurements from Mauna Loa Observatory were suspended as of Nov. 29, 2022. Observations from December 2022 to July 4, 2023 are from a site at the Maunakea Observatories, approximately 21 miles north of the Mauna Loa Observatory. Mauna Loa observations resumed in July 2023.


The complete Mauna Loa CO2 records described on this page are available.

Additional CO2 data from Mauna Loa and other worldwide sampling sites can be found using the GML Data Finder of public data sets.

These values are subject to change depending on quality control checks of the measured data, but any revisions are expected to be small.

How to reference content from this page

Dr. Pieter Tans, NOAA/GML ( and Dr. Ralph Keeling, Scripps Institution of Oceanography (


Further Reading