Daily Average Mauna Loa CO2:

Week beginning on Jan. 17: 415.18 ppm

Weekly value from 1year ago: 413.80 ppm

Weekly value from 10years ago: 391.63 ppm

Last updated: Jan. 25, 2021

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