Fig. 1.

Probability distributions for the total effective RF of carbonaceous aerosols from (A) contained combustion (CC) and (B) biomass burning (BB) from the four sets of analyses considered here. The four estimates are: (i) A*, AeroCom intercomparison study with internal mixing adjustment; (ii) H, Hansen et al. (6, 12); (iii) J, Jacobson (7, 9, 13, 14); and (iv) RC, Ramanathan and Carmichael (1). The nine models in A* are shown individually and collectively. The efficacies from H are applied to A and RC. Solid lines incorporate the snow albedo effect, assuming that it is caused by CC and BB in proportion to their BC emissions, whereas dashed lines exclude the snow albedo effect. The upper x-axis on (A) indicates for each RF value the number of years earlier CO₂ emissions must be cut to 50% of 2005 levels in a 500 ppm CO₂e stabilization scenario where CC carbonaceous aerosols emissions are kept constant rather than cut to zero. For example, the CC RFe from H (with 90% confidence range) is 0.23 ± 0.18 W m^-2; if CC emissions are not cut, CO₂ will have to reach 50% of 2005 levels 8.9 years (1.5–16.7 years) earlier than otherwise. See Fig. 2 for illustration.