Daily CO2 readings are updated here automatically with the latest atmospheric CO2 readings available from the Mauna Loa Observatory in Hawaii.
Data sources:
March 1958 to April 1974: Scripps Institution of Oceanography, May 1974 to present day: Dr. Pieter Tans, NOAA/GML
Last update: 2:35:02 AM on Apr. 25, 2025, Hawaii local time (UTC -10)
| Latest | One year ago | Change from previous year | ||
|---|---|---|---|---|
| Date | Reading | Date | Reading | |
| Apr. 24, 2025 | Unavailable | Apr. 24, 2024 | 428.42 ppm | n/a |
| Apr. 23, 2025 | Unavailable | Apr. 23, 2024 | Unavailable | n/a |
| Apr. 22, 2025 | 430.46 ppm | Apr. 22, 2024 | 427.21 ppm | 3.25 ppm increase (0.76 %) |
| Apr. 21, 2025 | 430.51 ppm | Apr. 21, 2024 | 427.29 ppm | 3.22 ppm increase (0.75 %) |
| Apr. 20, 2025 | Unavailable | Apr. 20, 2024 | 426.34 ppm | n/a |
| Apr. 19, 2025 | Unavailable | Apr. 19, 2024 | 426.97 ppm | n/a |
| Apr. 18, 2025 | Unavailable | Apr. 18, 2024 | 427.47 ppm | n/a |
| Apr. 17, 2025 | Unavailable | Apr. 17, 2024 | 427.04 ppm | n/a |
| Apr. 16, 2025 | 430.07 ppm | Apr. 16, 2024 | Unavailable | n/a |
| Apr. 15, 2025 | 430.27 ppm | Apr. 15, 2024 | 424.92 ppm | 5.35 ppm increase (1.26 %) |