I have been sent bits of information about particulate pollution and how this can reduce rainfall downwind of industrial areas and cities. I made some comment on this issue when I was in Hong Kong and somewhat surprised by the extent of the air pollution.*
Aaron Gingis has been a key proponent of the thesis. He has variously suggested that the reason we have a drought in south east Queensland is because of particulate pollution and that the solution to the drought in the Murray Darling Basin is cloud seeding.
I have often pondered Gingis’ claims while studying this map:
It suggests record low rainfall in our most heavily populated catchments. It was part of a blog post from David Jones in which he commented that Perth, Canberra and Melbourne catchments have all experience their lowest (or nearly so) rainfall on record. David didn’t mention pollution as a cause, and I have been meaning to ask him why.
Anyway, while some doomsayers have been more inclined to blame low rainfall on global warming, the Tasmanian Greens have commissioned Mr Gingis to prepare a report which has concluded that there will be a massive drop in rainfall in Tasmania’s north-east if a proposed pulp mill goes ahead.
According to ABC Online:
Mr Gingis said the ultra fine particles emitted by the mill will change the density of clouds and reduce rainfall in the north-east by up to 80 per cent…
“They make clouds actually constipated, in other words the clouds simply changing their metrophysics and not precipitating or precipitating much less.”
Mr Gingis has lobbied governments, irrigators, bloggers and others on the issue of pollution and reduced rainfall suggesting we can’t do much about the pollution and that the solution is cloud seeding.
It is interesting that ABC Online has just now reported the phenomenon and in the context of a campaign against a pulp mill proposed by timber company Gunns Ltd and there is no mention of cloud seeding as the solution.
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* See https://jennifermarohasy.com.dev.internet-thinking.com.au/blog/archives/001631.html :
I was recently sent the following very interesting papers on global dimming and its potential impact on rainfall in Australia: Rosenfeld, D. (2000) Suppression of rain and snow by urban and industrial air pollution. Science, Vol 287, pp 1793-1796. Rosenfeld et. al. (2005) Potential impacts of air pollution aerosols on precipitation in Australia. Clean Air and Environmental Quality, Vol 40, No. 2, pp 43-49. Rosenfeld, D. (2006) Aerosols, Clouds and Climate. Science, Vol 312, pp. 1323 – 1324. ABC TV Four Corners did a feature on global dimming in March 2005, the transcript and reference documents can be found here: http://www.abc.net.au/4corners/content/2005/s1328747.htm
Jennifer Marohasy BSc PhD has worked in industry and government. She is currently researching a novel technique for long-range weather forecasting funded by the B. Macfie Family Foundation.