Australia’s population debate cannot be separated from environmental decline, inequality and economic wellbeing. With continued growth adding pressure, zero population growth deserves a serious place in the national conversation.
Not one of Australia’s political parties with seats in federal parliament has a clear, comprehensive, coherent, constructive, population policy. Informed public debate is needed to assist the development of government policy to address several serious, neglected questions: for example, for various rates of population growth:
- What are the national and global environmental impacts of Australia’s population growth?
- What are the economic costs and benefits of Australia’s population growth?
- What are the social impacts in terms of provision of housing, health, education and infrastructure?
- What fractions of permanent immigration should be allocated to humanitarian, family reunion, and skills?
- What conditions should be placed on temporary immigrants regarding possible future transfer to permanent status?
This article responds to the first two questions.
Human civilisation faces existential threats from environmental impacts. Seven out of nine safe planetary boundaries have been exceeded. These are climate change, biodiversity, freshwater, land use, biogeochemical flows, ocean acidification and novel entities (i.e. chemicals, plastics, etc.).
The state and trend of Australia’s environment are poor and deteriorating. Local environmental impacts come from the global impacts together with increased local land clearing for housing and roads, pollution, resource extraction and invasive species.
At one conceptual level, we can disaggregate environmental impact into the arithmetic product of population, ‘affluence’ A (measured by GDP per person) and technological impact T (measured by environmental impact per unit of GDP). This relationship is the well-known I = PAT identity of environmental science. It is true by definition: with A and T defined as above, it reduces to I = I.
What it tells us is that, if we double population, while keeping ‘affluence’ and technology constant, then environmental impact doubles. Similarly, doubling ‘affluence’, while keeping population and technology constant, results in a doubling of environmental impact.
And, if we halve technological impact, e.g. by transitioning from fossil fuels to renewables, while population and ‘affluence’ are kept constant, then environmental impact is halved.
Clearly, population is one factor, but not the only factor, driving environmental impact.
On a global scale, growth in ‘affluence’ has had a bigger environmental impact than growth in population. But in Australia over the past 20 years the opposite has been true (see data discussed below).
The I = PAT identity has limitations – it only tells us about averages: average population, average economic activity per person, and average technological impact. To obtain more useful information, we must delve deeper.
Not every member of the population has the same environmental impact. A research study carried out for Oxfam International finds that the 10 per cent of the global population with the highest income is responsible for half of all global greenhouse gas emissions. These emissions come from the goods and services the rich purchase and their investments.
In comparison, the 50 per cent of the global population with the lowest income is responsible for only 8 per cent of emissions. Clearly, environmental impact and social justice are linked tightly together.
Almost all Australians are in the top 50 per cent of global incomes. Collectively, we are part of the global income group that’s responsible for 92 per cent of global emissions.
An even greater inequality exists if we measure wealth instead of income. According to another study by Oxfam International, since 2020 the richest 1 per cent globally have captured almost two-thirds of all new wealth creation.
Taxing both high wealth and high income would have multiple benefits: reducing greenhouse gas emissions and other environmental impacts by the rich and fostering a fairer society with a smaller gap between rich and poor.
Although it would be politically difficult in Australia, there are precedents: e.g. Norway, Spain and Switzerland have general net wealth taxes and 24 of OECD member countries, including the UK and the US, levy either an inheritance or an estate tax.
Australia has neither a wealth tax, an inheritance tax nor an estate tax.
Australian governments tend to resist constraining population growth because it increases GDP, creating the false impression that economic growth is improving the welfare and wellbeing of the people. But GDP is not a credible measure of welfare or wellbeing, as discussed in other articles published by P&I (e.g. here and here).
In Australia, from 2005-06 to 2025-26, real GDP grew by about 61 per cent while ‘affluence’, measured by real GDP per person, grew by only about 17 per cent. From 2022-23 onwards, ‘affluence’ actually decreased. These Australian Bureau of Statistics data confirm that GDP tells us very little about the material prosperity of Australians.
Wellbeing is better discussed in terms of indicators such as environmental quality, poverty level, income inequality, job skills, cultural diversity and the availability of universal public services.
Universal public (or basic) services comprise substantial programs for public health, education, housing, transportation, parks and other facilities, together with low-cost childcare and aged care. Together they comprise a social wage.
With appropriate government policies, immigration can fill gaps in job skills, increase innovation and technological advancement, increase economies of scale, and enhance cultural diversity and creativity. However, these benefits do not justify a rate of net immigration so high that it drives population growth.
Population growth is not essential for a prosperous society with a high quality of life. Each of the Scandinavian countries has arguably better public health, education, housing and transport systems than Australia. Each, except Finland, has a lower population.
To sum up, the economic benefits of continuing population growth in Australia have been exaggerated. The environmental impacts are substantial and deteriorating. However, total environmental impact is determined by ‘affluence’ and technology choice as well as population.
In theory, environmental impacts could be reduced by a substantial transition to green technologies and reduced ‘affluence’, while population growth continues at a modest rate. The government could reduce ‘affluence’ by providing universal public services and a job guarantee, or alternatively a universal basic income.
At present, as Australia is a long way from these transitions, zero population growth should be part of the public debate.
Dr Mark Diesendorf was originally a physicist who expanded into interdisciplinary research on energy and sustainability. Previously he was Professor of Environmental Science and Founding Director of the Institute for Sustainable Futures, University of Technology Sydney. Currently he is Honorary Associate Professor in the Environment & Society Group in the School of Humanities & Languages, UNSW Sydney. Web: https://research.unsw.edu.au/people/associate-professor-mark-diesendorf. Mark is the lead author of ‘The Path to a Sustainable Civilisation: Technological, socioeconomic and political change’ (Palgrave Macmillan, 2023).