Atmospheric CO₂
Atmospheric CO₂ has climbed to about 429.1 ppm (August 2026) — up roughly 113 ppm, about 35.9%, since records began at Mauna Loa in 1958.
Source: NOAA Global Monitoring Laboratory. Data through August 2026. Download the data (JSON).
About this indicator
Carbon dioxide is the greenhouse gas most responsible for modern global warming. It is released mainly by burning fossil fuels — coal, oil and gas — and by deforestation, and it lingers in the atmosphere for centuries.
The famous "Keeling Curve" from Mauna Loa in Hawaii has tracked CO₂ continuously since 1958. It rises and falls slightly each year as plants grow and die back, but the long-term trend is a steady, accelerating climb far above anything seen in the ice-core record of the last 800,000 years.
Why it matters: More CO₂ traps more heat near the surface, warming the planet and driving sea-level rise, more extreme weather and ocean acidification.