"A scaling theory for the size distribution of emitted dust aerosols suggests"......

[degrub]

here we go again

http://www.pnas.org/content/early/2010/12/23/1014798108.abstract

[Dr Mordrid]

Seems like every week there is a major problem with GCM's found, yet the warming community mantra changes not. Seems at some point someone needs to say 'never-mind until you get your act straight'.

[Brian Ellis]

This is very possible. Up to now, most studies have been on PM10, which usually settles fairly quickly except in strong winds, mainly because the dust is visible. PM2.5 and less can be true aerosols. Then there is the nature of the dust (traffic related, volcanic, ocean salt, desert dust storms etc) which have different albedos and particle shape; these have different residence times for a given particle size. Some. such as salt and some types of volcanic dust, "rain out" faster than others. Some make better nuclei for condensation. Some are denser than others and tend to remain more in the lower troposphere (layering). Yes, there are many variables and some are unresearched. Some have positive and some negative radiative forcing. Some are anthropogenic, others aren't. Those that aren't contribute to the base global warming while the anthropogenic ones influence man-made climate change, both negatively and positively. However, given that the atmospheric residence time of individual dust particles is short, their climatic influence is relatively small. Even the finest volcanic particles thrown into the stratosphere from major eruptions hardly cause a blip in the radiation received, lasting generally a maximum of 3-4 years, which is almost negligible on the climatic scale. Overall, the IPCC range of tolerances on dust and its effect covers most eventualities and has little influence on the overall results, compared with the radiative forcing of GHGs. Nevertheless, the more we learn, the more the tolerances can be tightened.