The average amount of CO2 in the Earth’s atmosphere shows a steady rise over the last two decades
The concentration of carbon dioxide (CO2) in the Earth’s atmosphere has been measured at Mauna Loa, Hawaii since 1958, and at five other stations subsequently. It shows a steady mean increase from 357 ppmv (parts per million by volume) in 1992 to 389 ppmv in 2011. Seasonal variations of about 5 ppmv each year correspond to seasonal changes in uptake of CO2 by the world’s land vegetation, influenced by the greater vegetation extent and mass in the Northern hemisphere.
The increase in atmospheric CO2 is primarily attributed to the combustion of fossil fuel, gas flaring and cement production and has been accelerating in recent years (IPCC 2007).
This graphic is part of the publication Keeping Track of Our Changing Environment