Population growth, distribution and composition drive environmental change
One of the drivers of environmental change is population growth and demographic change. Demographic change includes the movement of people within a country to new locations, and changes in the composition of the population (e.g. through changes in the relative numbers of different age groups).
Total population is determined by 3 factors: mortality, fertility and net overseas migration. Fertility and mortality rates are decreasing, but, during the past decade, net overseas migration has been the largest influence on the size of Australia’s population, representing about 60 per cent of growth.
In March 2016, Australia’s population was 24 million people—more than double the population in 1966. Assuming current trends, in the next 50 years, this number is projected to increase to between 36.8 and 48.3 million people (ABS 2016a).
Each person added to our population theoretically creates additional demand on natural resources to provide materials for shelter, energy and sustenance—although a direct one-to-one relationship between population growth and increased pressures on the environment cannot be assumed. The extent to which population increase leads to environmental change depends on a range of factors, such as:
- how many of us there are
- where and how we live
- the amount we consume
- the technologies we use to provide our energy, food, materials and transport
- how we manage the waste we produce.
Australia’s population has one of the most geographically distinctive distributions of any country, with 90 per cent of people living in just 0.22 per cent of the country’s land area (NSC 2013). At June 2015, 15.9 million people—around two-thirds of Australia’s population—lived in a capital city, and these areas generally experienced faster population growth than the rest of the country. Many areas that experienced strong growth were on the fringes of capital cities, where more land tends to be available for subdivision and housing development (ABS 2016a).
Generally, the most prominent growth outside capital cities between 2011 and 2015 occurred along the coast of Australia, particularly in Queensland. The concentration of Australia’s population near the coast, mostly in urban areas, creates substantial pressure on coastal ecosystems and environments in the east, south-east and south-west of the country (ABS 2015).
Inland rural population growth rates are generally lower than in urban and coastal areas, and rural populations have declined in some locations.
In coming decades, Australia’s capital cities are expected to experience higher percentage growth than their respective state or territory populations, resulting in a further concentration of Australia’s population in metropolitan areas.
Urban growth is already driving land-use change in Australia, with expansion in peri-urban areas (on the outskirts of cities and large towns) having direct impacts on the environment and the availability of farm land. This trend is expected to continue.
Well-planned, higher-density residential areas can reduce the need to expand into greenfield sites, and provide opportunities for more efficient energy use (a result of smaller dwellings) and more efficient transport. Poorly planned and executed urban growth can exacerbate environmental pressures and have direct impacts on biodiversity—for example, through land-use change and by changing the ability of ecosystems to mitigate floods.
The implications of the size, nature and distribution of Australia’s population for the natural environment, our heritage, and the built environment of our cities and regions are considered throughout the SoE 2016 thematic reports.