Each person added to our population creates additional demand on natural resources to provide materials for shelter, energy and sustenance. However, it cannot be assumed that an increase in population leads to greater stress on the environment. The extent to which population increase leads to environmental change depends on a range of factors, including:

• how many of us there are
• where and how we live
• the goods and services we produce (for both domestic and export markets) and consume
• the technologies we use to produce our energy, food, materials and transport
• how we manage the waste we produce.

Total population

Australia’s population has more than doubled in the past 50 years. In March 2016, the estimated resident population of Australia stood at 24 million people, an increase of 7.2 per cent since SoE 2011. On average, our population has grown by 1.3 per cent per year during the past 20 years. Figure DRV2 shows the percentage change in Australia’s population from 1860 to 2015.

This section draws on data from population projections from the Australian Bureau of Statistics (ABS; ABS 2008), the intergenerational reports (Australian Government 2010, 2015; ABS 2015a) and the Sustainable Australia report 2013 (NSC 2013).

Total population is determined by 3 factors: mortality, fertility and net overseas migration.

Mortality rates in Australia have fallen significantly during recent decades, adding to population growth and the proportion of older people in the population. Australia’s crude mortality rate fell from 6.7 deaths per 1000 people per year in 2008 to 5.4 deaths per 1000 people per year in 2015. Life expectancy for Australians continues to be among the highest in the world. In 2014, male life expectancy at birth rose to 80.3 years from 79.7 in 2009–11, and female life expectancy increased to 84.4 years from 84.2 (ABS 2015a).

Projected life expectancy at birth in 2055 is 95.1 years for men and 96.6 years for women. The number of Australians aged 65 or older (15 per cent of Australians in 2015) is expected to nearly double by 2061 (Australian Government 2010). Our ageing population will progressively affect the type and number of demands placed on environmental resources (Di Nunzio 2014, ABS 2015a). It will also continue to provide skills and resources for an increasing number of local community groups focused on the environment.

In its report on Australia 2030 scenarios, CSIRO notes that:

The aging population will be an asset, providing a wealth of skills, knowledge, wisdom and mentorship. However this will also present challenges, such as a widening retirement savings gap and rapidly escalating healthcare expenditure. This will change people’s lifestyles, the services they demand and the structure of the labour force. (CSIRO Futures 2016)

The total fertility rate is the average number of children a woman gives birth to in her lifetime; 2.1 is considered the fertility rate needed to keep the long-term population stable in the absence of changes in mortality and net overseas migration. Australia’s total fertility rate in 2014 was 1.80 births per woman, a decrease from the 2011 rate of 1.88 births per woman. Since 1976, the total fertility rate for Australia has been below replacement level (ABS 2015a).

Net overseas migration has been the largest factor influencing the size of Australia’s population, representing about 60 per cent of Australia’s population growth in the past decade. Annual numbers of migrants have varied widely, from a low of 30,000 in 1992–93 to a high of 300,000 in 2008–09. Net migration is an important strategy for offsetting the decline in Australia’s total fertility rate and demographic change associated with our ageing population.Assuming current trends, Australia’s population is projected to increase to between 36.8 and 48.3 million people by 2061 (39.7 million people by 2055) and to between 42.4 and 70.1 million people by 2101 (Australian Government 2015).

Demographic change

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).

The geographical distribution of Australia’s population creates distinct regional pressures on the environment. Most of Australia’s population is in the east, south-east and south-west. A large proportion of the population is concentrated in urban areas, notably the capital cities.

At June 2015, 15.9 million people—around two-thirds of Australia’s population—lived in a greater capital city. These areas generally experienced faster population growth than the rest of the country. Many areas that experienced strong growth were located on the fringes of capital cities, where more land tends to be available for subdivision and housing development (ABS 2016a).

Between 30 June 2013 and 30 June 2014, Melbourne had the largest growth of all capital cities (up by 95,700 people), followed by Sydney (84,200), Perth (48,400) and Brisbane (38,500). Perth had the fastest growth (up by 2.5 per cent), ahead of Darwin and Melbourne (both 2.2 per cent) (ABS 2015b).

Inland rural population growth rates are generally lower than those in urban and coast areas, and rural populations have declined in some locations.

Generally, the most prominent growth outside of 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 2015b).

In the 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. Current projections suggest that 74 per cent of Australians will live in capital cities by 2061 (ABS 2015a).

Under a scenario of medium population growth, Melbourne and Sydney are expected to have 8.6 and 8.5 million people, respectively, by 2061 (ABS 2013). Under the same scenario, Perth will have the highest percentage growth of Australia’s capital cities (187 per cent), increasing from 1.9 to 5.5 million people by 2061. Current strategic planning for the Perth–Peel region is for 3.5 million people by 2031.

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 natural environment and some of the most biologically productive lands currently used for agriculture. This trend is expected to continue and escalate.

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.