Historical Data
Atmospheric CO₂ — World
parts per million (dry air mole fraction). NOAA Global Monitoring Laboratory, marine surface sites.
Complete series
571 observations, January 1979 – July 2026
By decade
Average, minimum and maximum of reported values in each decade.
| Decade | Observations | Average | Minimum | Maximum |
|---|---|---|---|---|
| 1970s | 12 | 337 ppm | 334 ppm | 338 ppm |
| 1980s | 120 | 345 ppm | 337 ppm | 354 ppm |
| 1990s | 120 | 360 ppm | 352 ppm | 369 ppm |
| 2000s | 120 | 378 ppm | 367 ppm | 388 ppm |
| 2010s | 120 | 399 ppm | 386 ppm | 412 ppm |
| 2020s | 79 | 419 ppm | 410 ppm | 429 ppm |