In responding to long-term physical implications of net overseas migration to Australia it is proposed to address the impact of increased population on the natural and built environment in the following areas:

• scarcity of water resources through climate change
• loss of agricultural land through urban expansion and mining
• loss of biodiversity

Climate Change

In the first update to his 2008 Climate Change Review Professor Garnaut “was clear about the link between recent extreme weather events – from Black Saturday to cyclone Yasi – and global warming. … if we are seeing the intensification of extreme weather events now .. you ain’t seen nothing yet.” (Age 5/2/11) (1) The intensification of extreme weather events then must be taken into consideration when deciding on a sustainable population strategy for Australia given the demands an increased population will have on food production and water resources.

Most food producing regions are in the eastern states of Australia. Two of these states have in the last ten years been subjected to a ten year drought and this year Queensland and Victoria have experienced devastating floods. For example financial losses for agriculture in the Loddon river catchment (with farmland still under water three weeks after the initial deluge) is estimated to be between $1.5 billion and 2 billion. The Department of Primary Industries reports that more than 4400 kilometers of fencing and 218,000 hectares of grazing pasture and field crops have been lost. (Age 14/2/11) (2)

Recent experience of the ten year drought also demonstrated that lack of water supply is an absolute constraint on population growth in capital cities but especially in Perth which is utterly dependent on bore water and desalination plants both for agriculture and domestic water supply. Unfortunately desalination plants are expensive to run requiring vast amounts of energy. They also leave behind concentrated brine which can harm the marine environment.

Mining

The population that Australia could sensibly support is limited by the meager supply of fertile land close to reliable water resources. Unfortunately the land is in demand not only for agriculture and food productions but also for forestry, urban settlement, industrial development, mining, waste disposal and recreation. Most recently the commencement of coal seam gas mining in the Surat and Bowen Basins, the Darling Downs and Hunter Valley is impacting on farming and residential communities.
The coal seam gas industry plans to drill 40,000 wells in Queensland by 2030 with each well occupying at least a hectare of prime agricultural land. The Victorian Government has approved gas exploration in the Bay of Islands Coastal Park in the states’ south-west.

Not only will fertile land be lost to the coal seam gas industry but equally scarce water supply could be polluted unfit for drinking because of the method used in mining gas. To access the seam hydraulic fracturing is used where a mix of highly toxic chemicals and water is pumped hundreds of meters underground, forcing the rock to crack and release natural gas trapped in it. The problem is that a third of the liquid stays below ground and may leach into water supplies making it unfit to drink. The tragedy is that once the aquifer is contaminated it cannot be restored as a reliable water source.
Traces of cancer-causing chemical benzene have been found in water samples taken from Arrow Energy’s MoranbaH coal seam gas project west of Mackay. Benzene was also found in eight wells at Origin and Australia Pacific LNG coal seam gas wells last month. (Business Age 17/1/11)(3)

Food Security

Fertile agricultural land is under threat, as seen above, from mining interests, and closer to major cities, from expansion into urban growth corridors where market gardens once flourished close to city markets. The failure of planners to take account of the impact of alienating productive land is a continuing problem as they buckle to the pressure from developers who see an increased migrant intake as essential for the expansion of their construction industries.

Food security is also under threat due to the Australian Government’s failure to legislate to control the sale of prime agricultural land to foreign governments whose mission statement refers to their food security. (Hassad Foods & Qatar) Lack of a food security policy could lead to Australia becoming reliant on imported food.

Melbourne’s Water Supply

A comprehensive report into the long term physical implications of net overseas migration by the National Institute of Labour Studies Flinders University (4) claims that the water supply for Melbourne could become critical by 2050. Melbourne is substantially affected by climate modelling output that suggests a fall in average rainfall of 20% to 30% resulting in run-off for dams of under 50%. On these calculations by 2050 Melbourne is likely to have permanent water restrictions on use.

Biodiversity

Melbourne’s population is being planned literally around key biodiversity areas in the west adjacent to remnant native grasslands, and in the south-east adjacent to the Mornington and Westernport Biosphere Reserve. Only 5% of the original vegetation remains within the city’s Urban Growth Boundary. Natural ecosystems within the city and inner suburbs of the Port Phillip and Westernport Catchment Management Area (CMA) have been permanently altered according to the State of the Environment Report DSE 2008.

Concern continues over the loss of native grassland in the north and west areas of Greater Melbourne where native grasslands once covered 870,000 ha before clearing for agriculture and settlements occurred. Melbourne West Investigation Area concludes that there is a declining trend in the extent of biodiversity in the landscape where new urban expansion is planned.

Sustainable Population Strategy for Australia

Shortage of water and loss of agricultural land coupled with an intensification of climate induced floods and droughts calls for a limit to be set on the size of population for Australia.

Flinders University National Institute of Labour Studies (NLS) 2010, researched the impact of various levels of Net Overseas Migration (NOM) on Australia’s natural assets and built environment beginning with a literature review of previous studies. Griffith Taylor, Sydney University 1921, concluded that, on the basis of his research, because Australia was mostly desert, Australia’s carrying capacity would support a maximum of 20 million people.

Research continued on from Taylor’s work with various authorities, including the CSIRO, (Future Dilemmas 2002)(5), identifying resource and environmental variables, based on a large number of demographics, increasing greenhouse gas emissions. Regrettably more recent research and business lobbying appears to favour a big Australian future rather than Griffith Taylor’s sustainable population maximum of 20 million.

What has dramatically intruded into the debate in 2011 is the surfeit of water flooding farms in Queensland and Victoria and the time required to restore food producing land and crops. In many cases intensification of climate change induced drought and floods may spell the end of farming in certain regions leading to Australia’s costly dependence on imported food products.

Footnotes and Bibliography

• Manning, Paddy. “Garnaut’s climate update adds more heat to the debate.” Age 5 February 2011.
• Gray, Darren. “Flooded farmers still getting drought hand-outs.” Age 14 February 2011.
• Quinn, Karl. “Drinking water in filmmaker’s shock plot.” Age 13 November 2010.
• Flinders University National Institute of Labour Studies. (NLS) July 2010.
• Ibid (NLS)