Climate Monitoring and
Summary Report No. 26
Annual average emissions of carbon dioxide to the atmosphere
from global fossil fuel burning (blue histogram) and the increase
in global carbon dioxide remaining in the atmosphere each year (green
histogram), expressed in petagrams (billions of metric tons) of carbon.
The straight red line represents an average linear growth rate of
carbon dioxide in the atmosphere. On average, this growth rate has
represented about one-half of the fossil fuel emission over the years;
however, large interannual fluctuations in atmospheric carbon dioxide
growth rate are evident. This interannual variability is due to variations
in natural carbon dioxide sources and sinks, mainly terrestrial processes
such as photosynthesis and respiration, and oceanic uptake and release.
For the period 1980 to the present, the atmospheric carbon dioxide
growth rates were derived from data of the NOAA/CMDL Cooperative Air
Sampling Network, which currently comprises over 50 stations. Prior
to 1980, the annual growth rates were derived from Mauna Loa Observatory
measurements. Comparison of the global and Mauna Loa record after
1980 indicates that the Mauna Loa data are reasonably representative
of the global average growth rate.
U.S. Department of Commerce
National Oceanic and Atmospheric Administration
Oceanic and Atmospheric Research