The Issues

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Physical limitations on population growth

• Australia's capacity to sustain a large population is limited because the continent is largely arid with old, nutrient-poor soils and a variable climate.
• Only six per cent of the continent is arable¹.
• Dryland salinity threatens to destroy up to 17 million hectares of agricultural land by 2050^2,2a.
• Our rivers show severe signs of degradation through extraction, regulation by dams and other forms of habitat destruction, and increasing salinity is likely to make the water in many of them undrinkable and unfit for irrigation within a matter of decades, further reducing the possibility of large settlements, particularly inland^3,3a.
• The CSIRO predicts that by 2070, there will be a 1 to 6^oC warming over the continent. There is likely to be less rainfall in the southwest, parts of the southeast, and in Queensland. Where warming is combined with lower rainfall, there will be greater moisture stress⁴. This has significant implications for agriculture, critically, food production.
• The global oil extraction rate is currently four times the rate at which it is being discovered. While global per capita oil production peaked in 1979, the absolute peak is imminent and production will decline thereafter. Oil products (petrol, diesel, plastics, medicines, fertilisers, etc) will become increasingly expensive. This has huge implications for the economy, particularly manufacturing and food production⁵.

How many people can the Earth support?

       How many people can Australia support?

              How many people can other countries support?

The Optimum Population Trust is an environmental organisation in England whose concern is with the impact of population growth on the environment. Their research is based on climate change, energy requirements, impacts on biodiversity and other environmental factors. They recommend stabilisation and gradual population decrease globally and in the UK.

The Optimum Population Trust, determined that at the current standard of living (as determined by the WWF's Living Planet Report 2002), the optimum population for Australia is 10 million (rather than our present 20.4 million) and at a lower standard of living, it is 21 million.

Click the following link to download a spreadsheet that outlines the methodology for calculating sustainable population numbers for the earth and each country:

OPT Carrying Capacity spreadsheet (862Kb)

^References

^{1. http://www.auslig.gov.au/facts/dimensions/compare.htm}

^{2. State of Environment Committee. Australia State of Environment Report 2001. CSIRO Publishing. p 53.}

^{2a http://www.csiro.au/index.asp?type=mediaRelease&id=SaltAustraliasGreatestBattle&stylesheet=mediaRelease}

^{3. State of Environment Committee. Australia State of Environment Report 2001. pp 57-69.}

^{3a. http://www.csiro.au/index.asp?type=mediaRelease&id=Prwhitebook&stylesheet=mediaRelease}

^{4. CSIRO Atmospheric Research. Brochure. http://www.dar.csiro.au/publications/projections2pp.pdf}

^{5. http://www.peakoil.org}