Figure SPM-6: Stabilizing CO₂ concentrations would require substantial reductions of emissions below current levels and would slow the rate of warming.

1. CO₂ emissions: The time paths of CO₂ emissions that would lead to stabilization of the concentration of CO₂ in the atmosphere at various levels are estimated for the WRE stabilization profiles using carbon cycle models. The shaded area illustrates the range of uncertainty.
2. CO₂ concentrations: The CO₂ concentrations specified for the WRE profiles are shown.
3. Global mean temperature changes: Temperature changes are estimated using a simple climate model for the WRE stabilization profiles.Warming continues after the time at which the CO₂ concentration is stabilized (indicated by black spots), but at a much diminished rate. It is assumed that emissions of gases other than CO₂ follow the SRES A1B projection until the year 2100 and are constant thereafter. This scenario was chosen as it is in the middle of the range of SRES scenarios. The dashed lines show the temperature changes projected for the S profiles (not shown in panels (a) or (b)).The shaded area illustrates the effect of a range of climate sensitivity across the five stabilization cases. The colored bars on the righthand side show uncertainty for each stabilization case at the year 2300. The diamonds on the righthand side show the average equilibrium (very long-term) warming for each CO₂ stabilization level.Also shown for comparison are CO₂ emissions, concentrations, and temperature changes for three of the SRES scenarios.