[KayEyeDoubleDee]

(I'll caveat the following by pointing out that the word may is used an awful lot in the above)

Where (in terms of the different layers of the atmosphere) does this black soot settle? In other words, is it a lower layer phenomenon or upper layer? It would be interesting in light of the basic problem with the current models: Absence of upper level warming predicted to precede lower level warming.

This would also assume that the stuff really does absorb extra infrared (in other words more than the total which would be absorbed through other processes)

[cogitator]

Definitely lower layers in the atmosphere. But in terms
of the difference between the lower troposphere and surface
warming issue, it hasn't been mentioned as a factor.