Mauna Loa CO2

October 2021




Oct. 2021
413.93 ppm pending
Oct.2020 411.51 ppm pending
Oct. 2019 408.75 ppm pending
Last Update: Nov. 5, 2021 TBD
View Data: NOAA

Mauna Loa Observatory (MLO)  |  Atmospheric CO2
monthly mean concentrations  |  ppm = parts per million

Two independent records of CO2 changes are maintained in parallel at Mauna Loa.   A graph showing the two records together is available at the bottom of the Scripps CO2 Program website.  All-time monthly record highs for CO2 are recorded at the CO2 Records webpage. 

Use the tabs below to view the latest monthly CO2 data, charts and related links.


CO2 Past.  CO2 Present.  CO2 Future.