Figure
2 Some possible controlled paths
of year-by-year emissions of CO2
over the next 300 years that would hold eventual concentrations
below ceilings of 750, 550, and 350 ppmv. The projected path (solid
black line) from which each of the three departs is the projection
of IPCC scenario IS92a, from Fig. 1. The far-less stringent emissions
profile that would result from the extended Kyoto Protocol (in blue,
also from Fig. 1) is also shown. The horizontal dashed blue line
is the 1990 level.