Figure 3.3: Fossil fuel
emissions and the rate of increase of CO2 concentration in the atmosphere.
The annual atmospheric increase is the measured increase during a calendar year.
The monthly atmospheric increases have been filtered to remove the seasonal cycle.
Vertical arrows denote El Niño events. A horizontal line defines the extended
El Niño of 1991 to 1994. Atmospheric data are from Keeling and Whorf (2000),
fossil fuel emissions data are from Marland et al. (2000) and British Petroleum
(2000), see explanations in text.