If particulates are too small for water droplets to form, perhaps we should go back to less clean burning...
It's good that competing theories keep coming up. It does science, politics and the public no good that the greenies and their political acolytes have made it largely a closed shop of just CO2 = we're all gonna die. The first three paragraphs of Peter Schwerdtfeger's article are enough to be labelled a frontman for big oil in some circles.
I can understand water vapour having nothing to coalesce around might result in no rain. I can understand water vapour having plenty of stuff to coalesce around resulting in rain. I can't quite understand why particles of a particular size would both cause water vapour to coalesce around them and inhibit rainfall. What it sounds like to me is that big particles = rain, no particles = no rain, small particles = some kind of emulsion of water droplets.(In that the water is there, but is suspended in the air and doesn't fall) Does that sound about right?
Chinese and Israeli researchers have shown that the average precipitation on Mt Hua near Xi'an in central China has decreased by 20per cent amid increasing levels of man-made air pollution during the past 50 years. The precipitation loss was doubled on days that had the poorest visibility because of pollution particles in the air. This explains the widely observed trends of decrease in mountain precipitation relative to the rainfall in nearby densely populated lowlands, which until now had not been directly ascribed to air pollution.
It's a pity the article doesn't explain why the rainfall in mountain and densely populated are diverging. Both would be subject to increasing levels of minute particles inhibiting rainfall. A lack of precipitation when visibility is poor is surely because air is not circulating as it usually does rather than some just-the-wrong-sized particles.
I put a lot of stock in change of land use being behind any actual (rather than fiddled statistical) climate change. If the populated lowlands have become more densely populated over those 50 years there will be more heat from the urban heat island effect that may change things, plus better drainage leading to less standing water and less vegetation resulting in less water vapour reaching the mountain.
In the case of Kilimanjaro IIRC it has been suggested deforestation has created a more arid climate around the mountain.