Australia's future population — facing up to difficult choices

In the absence of a national population policy, Australia is moving towards a more or less stable population of around 23 to 25 million people in one or two human generations' time.

A new report by the CSIRO Resource Futures team looks at the future impact of three population/immigration scenarios on infrastructure, resources and the environment to the year 2050.

Our report focuses on the environmental aspects of population impact, with particular emphasis on the quality and quantity of water, soils, biodiversity, atmosphere and natural amenity.

The first scenario considers what would happen with a zero net immigration rate. The second concerns an immigration rate of 70,000 a year (the current policy setting) and in the third (high population) scenario the rate is set at 0.67 per cent of the current population per year.

Under the low scenario, Australia's population would be 20 million by 2050, the medium scenario gives a population of 25 million and the high scenario results in a population of 32 million by 2050. By 2100 the scenarios give between 17, 25 and 50 million people.

Significant progress toward a sustainable physical economy in Australia requires more than just managing our future levels of population. It will also require the simultaneous management of infrastructure, lifestyle, energy, international trade, inbound tourism and the technology incorporated in key machines and processes.

The scenarios show continued growth in a range of key sectors of the physical economy at least until 2020. Even under the low population scenario, declining household size, internal migration patterns and requirements for tourism accommodation will stimulate activity for the building industry. In terms of the physical economy, this growth gives us cause to be optimistic in the short term.

The reasons for optimism are that 20 years of assured activity gives the nation time to implement substantial innovation and that stocks of buildings, motor cars, passenger transport and freight systems that incorporate the cleanest, most advanced technology will have time to penetrate the national system.

And, as long as these trends eventuate, growth could underpin new export industries that are rich in services and information, which can substantially replace the current export mix.

Under our high-population scenario, the population is proportionally younger. The proportion of dependent people - important for health and welfare issues - is greater than for the low and medium scenarios.

The changing demographic structure envisaged in our scenarios raises important issues. First, regional Australia tends to age more than the cities, due to internal migration. The impact of regional aging is compounded by increasing age-related medical problems in the regions, compared to younger cities. Also, the demand for services such as education will fluctuate, because of slow-moving changes in demographic structures.

The report argues it is feasible to prepare the workforce and its infrastructure well ahead of time, to better accommodate these issues.