Fig. 4.

Comparison of the probability of meeting of the indicated temperature thresholds for the emissions pathways of the peaking and stabilization concentration profiles for 510, 550, and 650 ppm (600 ppm is not shown here). The probabilistic temperature calculations are based on the climate sensitivity PDF by Wigley and Raper (10) (a–c). Probabilities of meeting target for transient temperature increase above preindustrial levels in 2100 (a) and 2200 (b), while probabilities of meeting target for equilibrium temperature increase for the stabilization profiles (c)—target for the maximum transient temperature increase that is reached sometime between 2000 and 2400 (see Fig. 2d) for the peaking profiles. Note that in a, the P650 and S650 lines overlap; this also holds for the P550 and S550 lines.