Mauna Loa CO2

September 2019




Sep. 2019

408.54 ppm

408.55 ppm


405.51 ppm

405.59 ppm

Sep. 2017

403.37 ppm

403.27 ppm

Last Update: Oct 7 2019
Oct 7 2019
View Data: NOAA  |  CO2.Earth Scripps

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

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


CO2 Past.  CO2 Present.  CO2 Future.