Daily Average Mauna Loa CO2:
Week beginning on Nov. 3, 2019: 409.90 ppm
Weekly value from 1 year ago: 406.99 ppm
Weekly value from 10 years ago: 385.42 ppm
Last updated: Nov. 12, 2019 Source: National Oceanic and Atmospheric Administration; Mauna Loa Observatory has been monitoring C02 levels since 1958