Climate Monitoring and Diagnostics Laboratory Summary Report No. 26 TABLE OF CONTENTS

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