Daily Average Mauna Loa CO2:

Week beginning on May 31, 2020: 417.20 ppm Weekly value from 1 year ago: 414.28 ppm Weekly value from 10years ago: 393.28 ppm Last updated: June 13, 2020 Source: National Oceanic and Atmospheric Administration; Mauna Loa Observatory has been monitoring C02 levels since 1958