Population and the natural environment

Bill McCormick, Science, Technology, Environment and Resources Section

Humans affect the environment in a variety of ways, including:

  • through the consumption of energy and resources
  • through the discharge of wastes and pollutants
  • through the displacement of plants and animals and the modification of natural ecosystems by agriculture, and
  • by cities, transport systems and industry.

Ecosystem services

Natural and modified ecosystems provide humans with:

  • provisioning services such as water, food, fibre, biomass fuel, genetic resources
  • regulating services such as climate regulation, flood and drought mitigation, water purification, pollination, disease and pest regulation and control
  • cultural services, such as recreation, aesthetic values, and heritage, and
  • supporting services, such as soil formation, nutrient cycling and primary production.

Modification of these ecosystems can reduce the effectiveness and amount of these services.

Sustainable population

In June 2010, the Australian Government appointed a Minister for Sustainable Population to develop a sustainable population strategy, ’underpinned by respect for the environment and respect for the needs of Australians requiring good infrastructure and services’.

There are calls to set population targets for Australia. These often relate to the number of people that would be the optimal population, rather than a sustainable population. Estimating the number of humans that Australia can support without damaging the natural environment (that is, the sustainable population or ‘carrying capacity’) is not readily possible; it depends on a number of variables, including:

  • the lifestyle and level of per capita resource consumption
  • the location of the population around the country
  • the quantities of the various pollutants that are discharged into the air, soil, water and biological systems
  • the sources and types of food and how and where they are produced
  • the location (source) and types of energy consumed, and
  • the location (source) and types of resources (for example, water, soil, minerals) used to make products that are consumed.

While it is difficult to estimate a specific sustainable population level there is no question that we need to eventually stabilise Australia’s population. There are limits in terms of the ability of the environment to supply resources and the ability of it to absorb waste products. Some commentators argue that we have already exceeded sustainable population levels for Australia.

Ecological footprint

The term ‘ecological footprint’ is used to assess the impact of individuals, cities or countries on the environment. One definition of ecological footprint is a measure of how much biologically productive land and water an individual, population or activity requires to produce all the resources it consumes and to absorb the waste it generates using prevailing technology and resource management practices’. Several Australian states and territories have calculated their ecological footprint.

Victorian ecological footprint

‘The average Victorian resident has an Ecological Footprint of 6.83 global hectares, more than three times higher than the world average. This equates to a total Footprint of 33 million global hectares, or 147% of the land area of Victoria. However, a part of Victoria’s Ecological Footprint will be located in other parts of the world to provide the wide range of goods and services consumed by its residents. The Ecological Footprint consists of both actual (real) land (arable land, pasture, forests, built land etc.) and “carbon land” (the land required to absorb the carbon dioxide emitted through the consumption patterns of a given population)’.

Different levels of consumption between populations will affect the environmental impacts of those populations. Altering consumption patterns to reduce the impact may enable the population of a country to increase, without putting further pressure on the environment. This may mean consuming less, but alternatively, the impacts of consumption can be cut by introducing technologies that reduce energy use, waste products and increase efficiency.

Intensification of agriculture

An increasing population requires more food and other primary products. Growth without end means that limits will be eventually reached in terms of the area of suitable agricultural land able to produce food and fibre needed for consumption and export. Population growth means growth in agricultural production, a trend that has been occurring for many years. Such an increase, whereby more food is produced from less land, is feasible up to a point, but can have major impacts on the environment if not managed properly. If practised sustainably, there is the potential to reduce, or at least minimise, these impacts. Methods of achieving this include:

  • changing farming practices, for example, improved management of livestock wastes or agro-forestry, to reduce greenhouse gas emissions
  • using improved plant breeds with increased water use efficiency and genetically modified crops to reduce pesticide use, and
  • precision agriculture to deliver water, nutrients and pesticides to the crops when and where they are needed, thus reducing consumption and offsite environmental impacts.

Comments

An increasing population will make it more difficult to meet environmental commitments. For example, to reduce Australia’s carbon emissions from year 2000 levels by five per cent by 2020, while the population is increasing to 27 million, means a reduction in per capita emissions by almost 20 per cent. Thus, population growth means that ways must be found to reduce individual footprints.

Library publications and key documents

B Foran and F Poldy, Future dilemmas: options to 2050 for Australia’s population, technology, resources and environment, report prepared for the Department of Immigration and Multicultural and Indigenous Affairs, CSIRO, Canberra, 2002, http://www.cse.csiro.au/publications/2002/fulldilemmasreport02-01.pdf

T Wiedmann, R Wood, J Barrett, M Lenzen and R Clay, The ecological footprint of consumption in Victoria, report prepared for the Victorian Environment Protection Authority (EPA Victoria) by the Stockholm Environment Institute at the University of York and the Centre for Integrated Sustainability Analysis at the University of Sydney, 2008, http://epanote2.epa.vic.gov.au/EPA/Publications.nsf/2f1c2625731746aa4a256ce90001cbb5/6a4f318c29647984ca2574710004e3ad/$FILE/ATTAD7EZ/1269.pdf

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