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 http://www.jennifermarohasy.com/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 is a critical thinker with expertise in the scientific method.
Mr Gingis claims of an 80% reduction in rainfall due to one more factory (in this case a pulp mill) in a heavy industrialised area with BHP’s Temco, Comalco and a power station must be of great alarm to people in Tasmania that depend on rainfall, especially those that grow trees!
Yet according to the Federal Department of Environment and Heritage he has made these sort of claims before: “that annual rainfall in the Snowy Mountains and in the Victorian Alps has been reduced by at least 30 percent over the past 50 years. He identifies the cause of this decrease as being industrial pollution from activities near Adelaide and near Geelong”
Luckily for the rainfall of north eastern Tasmania the DEH has investigated these claims about the Snowy and found “it has not been established that this has had any significant effect upon annual precipitation in these regions. Indeed the average annual precipitation in most areas of Southeastern Australia has shown an overall increase over the past 50 to 100 years.”
Perhaps the greens should admit that they just hate industrial forestry rather than trying to spread fear about a new factory that won’t get approval unless it meets the environmental standards already set by the Federal and State Governemnts.
Strange – I thought all this came out of Mather’s work in South Africa which enhanced rainfall. {Graeme Mather died in 1997}
Journal of Applied Meteorology
Article: pp. 1134–1146
Coalescence Enhancement in large Multicell Storms Caused by the Emissions from a Kraft Paper Mill
Graeme K. Mather
CloudQuest (Pty) Lid., Nelspruit, South Africa
While conducting a randomized seeding experiment, a storm was selected whose microphysical characteristics were so far from what was expected, given the existing thermodynamic environment, that some explanation was needed to account for the apparent errant behavior of this storm. More than a decade of sampling at −10°C using the project Lear jet has led to a simple classification technique, based on cloud-base temperature and buoyancy, which predicts the absence or presence, and to some extent the degree of coalescence (coalescence-freezing) precipitation growth in local convective storms. The unusual nature of this storm was recognized against this extensive microphysical database. The probable cause is attributed to emissions from a Kraft paper mill 10 km south of the storm’s position. The mill had recently undergone an expansion program that had quadrupled its output of paper products.
Using the radar characteristics of this unusual storm as a guide, a search of one season of radar data revealed the existence of five other similar storms, all within about 30 km of the paper win. These records indicated that the storms apparently modified by the paper mill tended to last longer, grow taller, and rain harder than any other storms recorded on that day.
The new awareness of this apparent inadvertent weather modification by the paper mill led to launching missions to intercept clouds growing in the vicinity of the mill. Storms, apparently altered by the mill, were sampled and compared to other nearby storms. The most singular feature of the modified storms was the appearance of lame (>4 mm) drops at the most common sampling level (−10°C), indicating an accelerated or enhanced coalescence precipitation formation process.
Measurements in a field of cumuli indicated a broadening of the cloud-base droplet spectra in clouds affected by the emission of the mill. It is the addition of this “long tail” to the cloud-base droplet spectra that is apparently turning on or at least enhancing coalescence in affected storms.
For anyone interested go to Google Scholar and you can Mather’s other published work on hygroscopic cloud seeding (vis a vis silver iodide)
http://scholar.google.com/
Try a search on “Mather cloud seeding paper mill”
Daniel Rosenfeld has done lots of work on suppression of rainfall processes from pollution including the Indonesian fires in the 1990s.
http://www.earth.huji.ac.il/data/pics/PWFEB01rosenfeld.pdf
Again try a Google Scholar on ” Rosenfeld cloud rainfall” with or without “Indonesia” and “Amazon”.
What is even more interesting is that maybe the Asian pollution cloud indirectly affects rainfall distribution in northern Australia by moving the circulation patterns !
http://web.maths.unsw.edu.au/~matthew/lr_aerosols.pdf
So looking at David’s map with an eye for pollution inducing rainfall decline you might say where’s Sydney’s big spot. And Adelaide and Port Pirie. Why is Shoalwater Bay so dry and a big deficiency behind Fraser Island.
Has SE Qld’s air pollution been improving? If so why weren’t deficiencies worse a decade ago?
What happens with big macroscale effects like El Nino – 1991-95 saw a major drought from Charters Towers to Toowoomba in the sub-coastal zone – worse on record at that time. Why not do a desktop study to see if circulation changes or El Nino explains the problem. Met Bureau?
Is cloud seeding in a drought a bad idea if no clouds to seed. So only useful in making average years better. Have we even thought properly how we would use the technology.
Does cloud seeding steal someone else’s rainfall so will Toowoomba sue Brisbane? Will Eden-Monaro graziers sue the Snowy Mountains trial?
CSIRO gave cloud seeding away suggesting little effect and too long to get a statistically significant result (like 20 years!). Western Tasmania maybe being the exception. What gauge network would we need in SE Qld given the spotty nature of thunderstorms to pick up a trend.
Certainly cloud seeding changes cloud behaviour but would it have rained anyway? You a good double double blind trial. And how do you circumvent the years/time problem. Maybe new technology with lidar and doppler radar can help to speed analysis and experiment time up. Certainly the Thai government seems to be investing. Google “Thailand cloud seeding”.
Are hygroscopic salt flares (Mather) better in northern Australia than traditional silver iodide?
So is it snake-oil or breakthrough. Very hard to tell IMHO. Should governments invest. If they don’t do it properly i.e. do some quick flights in a drought – it’s little better than a political gesture. Hard call?
Perhaps we should consider Queenslanders are suckers for this sort of thing.
The Charleville Steiger Gun
http://www.queenslandholidays.com.au/things-to-see-and-do/steiger-vortex-rainmaking-guns/brochure.cfm
To the south of town (on the western side of the road, in front of the scout hall) is the Steiger Gun. This bizarre piece of Western Queensland history is captioned: ‘Steiger Vortex Rainmaker Gun. One of ten guns used by the Queensland Government Meteorologist Prof. Clement Wragge at Charleville, September 26 1902.’ It was a vain attempt to induce a deluge and thus break the drought which had been going on since 1896. Wragge’s novel approach was to send blasts of air into the atmosphere. He persuaded the authorities in Brisbane to build Steiger guns which he duly placed around Charleville. They were all filled with gunpowder and ignited. Nothing happened. That night Wragge addressed a group of local citizens in Aeschimann’s Hall in Charleville and, so rumour has it, was greeted with considerable scepticism and derision. (Sort of like this blog !) He left town the next day.
When I last looked, which was a few years ago, I remember seeing a general trend of improvement in air quality over our cities including in particulate pollution? This is a real problem for Gingis and some of this recent claims in IMHO? But I’m keeping an open mind and generally agree with the thrust of Luke’s questions and comments.
An 80% rainfall reduction in the NE of Tasmania is not all the greens claim the pulp will do!
According to Greg Barns the greens claim that pollutant emissions could extend to New Zealand, 1600 kilometres away, and cause a reduction in the New Zealand ski season by five days.
There will also be damage to New Zealand’s agricultural sector because pollutants from the pulp mill will suppress rainfall.
For these and other alarmist predictions Greg’s opinion piece is worth a read at
http://www.news.com.au/mercury/story/0,22884,20545497-5006550,00.html
Jen’s been wise to include the BOM reduced rainfall map and add “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. It’s my guess David can’t say why even if he had a hunch.
But let’s be clever and say cloud seeding won’t fix things regardless of the atmospheric dust (er sorry; particular pollution).
Jennifer there are no clouds to seed over much of the country for most of the time. Readers can easily imagine a withered up pilot crumpled under the wing of his old plane fully loaded with silver iodide waiting for the big chance. The only thing up in our sky right now is some very dry bullshit.
In fact; there is a warning on ABC midday news telling people (young & old) in my region to avoid dehydration in the hot weather forecast later this week.
Readers may also no there is not much secondary industry in the Murray Darling Basin. As a former West Coaster; we need clag to make clouds over land.
Cinders comments but can’t find the source: “that annual rainfall in the Snowy Mountains and in the Victorian Alps has been reduced by at least 30 percent over the past 50 years. He identifies the cause of this decrease as being industrial pollution from activities near Adelaide and near Geelong”
I went back to this report – Aron Gingis & Ian Searle on ABC 2003
http://www.abc.net.au/landline/stories/s933799.htm
But I don’t need other peoples stuff like this to have an opinion after half a lifetime watching paper mills and clouds. Burnie had a pulp and paper mill complex in production for the best part of a century. I never heard a complaint from Penguin, Ulverstone or Devonport about lack of rain. We won’t look at Wynyard because it’s on the wrong side. Note: Living or working near Mt Read as we once did is even more on the wild side (I miss it).
http://www.bom.gov.au/announcements/media_releases/tas/20050601m.shtml
The process of turning wood into pulp actually makes clouds unless its groundwood pulp. When I worked at Burnie on the brand new continuous digester the exhaust steam sometimes went high in the sky after combining with the digester exhausts next door but it often rained on the nearest hill. The whole area was covered in its outfall.
Elsewhere we had better success with outfall (mostly furnaces not digesters) after we put flutes on the stacks. Luke will appreciate that I watched vortexes making clouds in a few places. But I doubt Luke will appreciate how bushfires also make rain in the same way.
Cinders will appreciate that governments listen to scientists like Aaron not practical blokes like you and me.
Sydney’s air quality has improved for a number of reasons,
– cleaner running more modern diesel motors
– ditto petrol
– cabs run on gas
– decentralisation of industry (and subsequent urbanisation of inner city areas)
It can get pretty smokey out towards Liverpool, esp in winter.
Cinders – this seems at odds with Mather’s work that rainfall was “enhanced” downwind of the kraft paper mill (if I read it right).
It’s the city pollution/forest fire smoke that is “supposed” to suppress rainfall formation processes.
Despite the fact that Australian dust from our dust storms may find their way to NZ alps I find it incredible that any pollution would be concentrated enough at that distance to do anything (but does anyone have anything?).
Jen – I think I have seen an “answer” to the decrease in pollution that it’s very dependent of a particular particle size and that may be a component of modern emissions. Dunno really – long bow?
And just to be clear – I think area of rainfall enhancement is very interesting and maybe new technology like doppler radar and lidar can speed things up. But should we modify the weather or invest more in forecasting and rolling with the dry spells/droughts i.e. not fighting the odds. Anyone?
Another modication technology I understand is used by orchardists at Gayndah on citrus and by fruit and vegetables growers at Stanthorpe are anti-hail cannons – to suppress hail formation – but do they work ? I don’t know.
Nevertheless here we have a different bunch of producers complaining that they do very well and are stealing rainfall.
http://www.abc.net.au/rural/qld/stories/s1064758.htm
http://www.abc.net.au/news/australia/qld/widebay/200407/s1149949.htm
Here’s some more great anecdotal stuff on Steiger guns in Austria and Clement Wragge.
http://www.austehc.unimelb.edu.au/fam/0825.html
Taz – I bow to your superior observations of cloud physics.
Taz,
To help you through the mass of information at the Department of the Environment and Heritage this page http://www.deh.gov.au/water/publications/cloud-seeding/claims.html is part of the consultants assessment of the Gingis submission.
The page also links to the Departmental Consultant’s conclusions and executive summary.
From the map, this thing does not ring true. A huge area from little industrialised Brisbane, but none from Adelaide, & stuff all from Sydney. Then another area on the Vic/SA boarder.
Most of those shown are not down wind,[prevailing wind] of the claimed source.
On this diagram the theory looks a little shaky.
To suggest that one mill could have more effect than Sydeny also stretches credibility.
If the theory is right, they’ll have to find some other sources, than industry, & that may not suit the agenda.
The meterological issue with all this is that I suggest there may have been changes to the southern hemisphere circulation (possibly to do with greenhouse, natural variation and ozone depletion). So how does one disentangle all these different assertions – see for example – http://www.cmis.csiro.au/healthycountry/updates/sep05/story3.htm
Hasbo – I think they’re implicating automobile emissions as well as industrial but your comment still holds.
Luke, I spent my last school years on an orchard at Young, NSW. We were surrounded, on 3 sides, by the largest producers in the district.
They all fired off hail rockets, when ever hail threatened. We never got hail, although near by areas often did.
I wondered for years, & the science honors class studdied, the reason for the hail distribution.
Did the rockets work?
Despite this huge application of mental power, the question remained unanswered.
Hasby – really great story – unfortunately for the fruit to really know if it worked we’d have to give you a randomised and sealed envelope which said fire or do not fire every time you thought about launching. And do that for 10 years. 🙂 The owner however may might not have approved of any “destructive sampling”. 🙂