Daily Average Mauna Loa CO2:

Week beginning on June 7, 2020: 416.27 ppm Weekly value from 1 year ago: 413.77 ppm Weekly value from 10years ago: 391.79 ppm Last updated: June 24, 2020

Source: National Oceanic and Atmospheric Administration; Mauna Loa Observatory has been monitoring C02 levels since 1958