THE AGE OF DUST


Australia is in the grip of a ‘dust age’, a five year-long spell in which the winds sweep tens of megatonnes of topsoil from the face of the continent.

“Dust is a measure of the care we are taking of Australia, just as the sediment in a river reveals how you are looking after its catchment,” says Professor Grant McTainsh, who heads the dust research team in the Desert Knowledge Cooperative Research Centre.

“Up till 2001, we thought we were getting better at it, based on the previous 40 years’ data. Then a major dust era erupted, from 2002-04, which still persists in NSW and parts of northern SA and western Queensland.”

A single giant dust storm took 4.85 million tonnes of soil, Prof. McTainsh and colleague Dr John Leys, calculated. In the same year 20 other events took over a million tonnes apiece. Accentuating the continent’s violent contrasts they recently observed a huge dust plume rising right alongside a flooding creek.

One of the reasons Prof. McTainsh and his team can be so precise about the scale and origin of dust storms is a newly-formed network of ground observers spread across the continent who supplement the satellite imagery with details of the dust colour (indicating its origin and composition) visibility (indicating volume) and wind direction, things not easy to determine from space.

The Dust Watch network was established in 2002 in NSW by Dr Leys from the NSW Dept of Infrastructure, Planning and Natural Resources and Prof McTainsh from Griffith University. Today it has 200 volunteers – mainly enthusiastic pastoralists – who report in whenever they see a dust storm brewing. Some race it in their utes to assess its speed and use fencelines to calculate visibility.

The network has also given rise to the “dusties”, a new inland sport which involves tracking a storm and having one’s picture taken in front of vast rolling clouds of red or grey dirt that frequently dwarf the spectacular 1983 cloud over Melbourne’s CBD.

But Dust Watch has its serious side. Since 2002 the team has charted 15 events which exceeded safe health limits for breathability. And all of the events speak of lost topsoil, lost nutrients, the land being stripped away and sometimes, gone for good.

In bad events, the plumes extend far across the ocean, stretching halfway to South America and Africa, besides dyeing the New Zealand snows pink. In such events, Prof McTainsh says, cubic kilometres of Australia are lost – far more than is exported by our rivers as sediment.

While today’s Dust Age is, perhaps, not as ferocious as those which accompanied the terrible droughts of the 1890s and 1940s, it is still possibly the third most severe in Australian history.

“This is a desert country, and you have to expect dust,” explains Prof. McTainsh. “A widespread drought, like the current one, is like a big broom sweeping tens of millions of tonnes. The question is: how much is attributable to human activity?”

“We think, on the whole, that Australians are getting better at keeping ground cover on the continent, especially since the rabbits were cut back by calicivirus. But this is still a 1-in100 year drought, and it exposes any weaknesses in our management.”

The Dust Watch network set up under the Desert Knowledge CRC is helping to pinpoint the sources of dust, enabling land managers and policymakers to take corrective action. It is building awareness of the scale of the problem and determination to correct it among inland landholders.

DustWatch is also building partnerships with state agencies and community groups. The Lower Murray Darling Catchment Management Authority, the NSW Dept of Infrastructure, Planning and Natural Resources and the Desert Knowledge CRC are collaborating together to monitor wind erosion and assess the effectiveness of the CMA’s investment strategies.

DustWatch has also come to the attention of the Japanese Meteorological Agency. Recently Dr Masao Mikami visited the Lower Murray Darling Catchment Management Authority to investigate the possibility of a cooperative research project.

Dust is also providing a fascinating new way to ‘read’ the continent and its constant changes. Prof. McTainsh is planning to recruit inland primary schools to join the Dust Watch team, and to put their reports on the web. Thus, he hopes, a future generation of Australians will come to the management of their land already equipped with an understanding of its fragility and its cycles.

More information:

Professor Grant McTainsh, Desert Knowledge CRC and Griffith University, 07 3875 7680 or 0409 279 700

G.McTainsh@griffith.edu.au Dr John Leys, Desert Knowledge CRC and NSW Dept of Infrastructure Planning and Natural Resources, 02 6742 9505 or 0419 634 554

John.leys@dipnr.nsw.gov.au Katie Vargo, Desert Knowledge CRC, 08 8950 7122 or 0428 102 935 Katie.Vargo@csiro.au