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About 100 billion humans have lived on our planet in its entire history. This means that about 7-8% of all the humans that have ever lived, are living today


The greatest challenge for sustainability science is to provide policy makers with reliable and objective indicators for the influence of population numbers on our society, economy, and environment – at the global, national, local, and individual scales. These metrics are the scientific basis for critical policy discussions serving as a community cost-benefit analysis.

Assessing environmental sustainability requires not only absolute population numbers, it must also include individual (per capita) resource consumption on the assumption that, in general, greater resource consumption equals greater environmental impact. So, population numbers must always be related to consumption levels. The significance of these two statistics is most evident as people in developing countries aspire to the high consumption lifestyles of those living in Western societies.

We have now entered an era of human planetary stewardship and human population number must be a key parameter in our decision-making.

Redhead Day

A Gathering of Redheads

Courtesy Wikimedia Commons

Our population numbers both collectively on the planet and within individual nations bring to a head a whole host of contemporary issues engaging global economics, socio-politics and environmental concerns: the carrying capacity of the Earth; the global management of poverty; the absolute necessity for growth in the global capitalist economy; the global management of political and environmental refugees; global resource use, especially as it relates to climate change and environmental degradation, most notably, but not exclusively, the specific resources of water, food and energy.

We still have little idea of what constitutes desirable population numbers or the appropriate means of population regulation should that be necessary. Economists demand a vibrant and growing economy as a prerequisite for jobs and economic security: this is a non-negotiable starting point for all major political parties. Without economic growth there is stagnation which is detrimental to everyone but especially those who are least able to cope, poor people in developing countries. Economic growth is an essential part of bringing people out of poverty and globally the growing population of the third world aspires to the resource-hungry lifestyles of the West.

The program of economic growth might be seen as part of the historical path for the future, the less fortunate at last catching up with the currently more privileged. But things are not that simple. Environmental scientists and those in favour of a ‘green’ economy point out that growth depends on resources, many of which are finite and that indefinite growth of the population and economy, apart from being a logical impossibility, places unsustainable demands on the environment. As the world population moves from 7 billion to at least 9-10 billion by 2050 we are already consuming resources and creating waste at a rate greater than the Earth can sustain. This is not a trivial matter; it is what future generations will inherit. We need the most accurate possible information on which to base future global management.

Human migration and population increase from about 100,000 BP to the present, then projected to 2100

Most significant phases occur as a rapid population explosion following the Industrial Revolution
and then the ‘Great Acceleration’ following World War Two.
Courtesy: American Museum of Natural History

Mathematics of growth

A steady growth rate (adding a fixed proportion of the total population from year to year) produces exponential growth that compounds over time. The ‘doubling rate’ can be calculated using the formula – 72 ÷ ‘growth rate’ – so a population growing at 2% p.a. would double in size every 36 years. With a steady growth rate of 3% p.a. a city of 2 million in 2000 would, by 2100, have a population of more than 32 million.

Growth is not limitless and it therefore becomes necessary to ask at what point it should be regulated and in what way.

Biology of growth

Biological studies on the growth of populations of organisms show that numbers increase until either they come into equilibrium with their environment (determined mainly by resource availability s but also predation and other factors) or there is a repeated pattern of flourishing and collapse or if numbers greatly exceed sustainability then there may be a sudden and total collapse leading to extinction.

Both authors of the theory of evolution, Charles Darwin and Alfred Russell Wallace, were deeply influenced in their thinking by the work of curate Thomas Malthus who observed that human population increases until it is reined in by (birth) control, famine, war or disease.

The graph of human population growth, it must be admitted, has the alarming character of the exponential growth of populations that occurs before resources run out, or the ‘boom’ before the ‘bust’ of a stock market crash. In the past ‘local’ crashes, even those of the two world wars, were gradually overhauled. A global crash today would be catastrophic. Apocalyptic scenarios may be unproductive but we do need to engage seriously with the problem.

Global population

United Nations statistics give the global population at the end of 2013 as 7.2 billion with a growth rate of 1.14% (82 million p.a.) with a projection to 9.6 billion by 2050 which will require 70% more food each year than now.[5] 


Baron von Mueller

Human population growth

The graph extends from 10,000 BCE projected through to 2100 CE.
Courtesy – American Museum of Natural History

From the above graph we can see that, even with the advent of settled communities following the hunter-gatherer societies of pre-history, in relative terms the first indication of increase came about 2,500 years ago coinciding with the burgeoning of Mediterranean and Chinese cultures during the Axial Age. However, until about 1300 CE across the world the the standard of living was relatively uniform with subsistence agriculture the prevailing occupation and a higher standard of living confined to small ruling elites. From about the 13th to 14th centuries in the West surplus production allowed economies to grow and new technologies to thrive.

A major population spirt becomes evident when vast quantities of cheap concentrated energy, as fossil fuels, become available, powering the Industrial Revolution.

 From 1700 to 1900 Europe’s population tripled from 122 to 421 million, that of China trebled from 150 to 436 million, and India’s doubled to 290 million. One especially dramatic statistic of the Age of Exploration is that around the 16th century at least 90% of native (non-European) populations visited or occupied by Europeans was killed by European epidemic diseases. World-wide the number of people living in cities increased from 2% in 1800 to 10% in 1900 (it exceeded 50% for the first time in 2010). In England of 1800 75% of the population was rural, employed on the land, but by 1900 had moved from farms to factories, rural to urban, those employed in agriculture, forestry and fishing decreasing from 25% in 1831 to 9% in 1901. London remained the largest city in the world through the 19th century, its population increasing from about 1 million in 1800 (only then overtaking the population of Ancient Rome at its height) to about 6.6 million in 1900, with associated epidemics and pollution, especially smog and cholera, and the replacement of wildlife with a human commensal fauna of rats, mice, cockroaches, sparrows, pigeons, fleas and the like.[4]

With the renewal of economic activity in the 1950s after the depravations of two world wars, and with yet more sophisticated technology, energy use, communication and trade, the world again redoubled its rate of growth to enter a phase of ‘population explosion’ that has been referred to as the ‘Great Acceleration’.

World population 1800-2100

United Nations “high”, “medium” and “low” world population estimates for 2100

Historical estimates of US Census Bureau are in black. High estimate for 2100 is 16 billion, lowest estimate suggests a decline to 6 billion from a peak of over 8 billion
Courtesy Wikimedia Commons


The above graph places global population on a shorter time scale from 1800 and projecting through to the year 2100, showing clearly in blue the Great Acceleration that began in the 1950s.

Populations in affluent developed countries are now slowing down towards a plateau of steady self-replacement although population in the developing world is still increasing rapidly. Barring major unforeseen circumstances the world population of about 6 billion in the year 2000 will increase by at least 3 billion to 9 billion between 2050 and 2100 (the global population passed 7 billion in late 2011). In the 21st century there will be rapid population growth in the poorest countries, with little growth and possibly decline in affluent countries where the relative proportion of aging people is on the increase.[2] With the likely increase of world population in 2050 to 50% over current levels the management of population during the next 50 years is critical.

The proportion of the world population living in cities surpassed 50% in around 2014.

Graph showing urbanization from 1950 projected to 2050

Courtesy Wikimedia Commons – Akantamn – Accessed 14 October 2020

The price of progress

The growth of economies and populations is a symptom of success that has been coupled with major advances in technology, sanitation, and medicine. Globally, on average, we live longer, are better educated and more wealthy. Poverty and child mortality have been greatly reduced. Our material lives are enhanced by sophisticated technologies, not just smartphones and the internet, but industrial agriculture etc. etc. Violence is also, on average, in decline.

The irony is that social progress is not an unsullied ‘good’ – there is an unplanned and unwanted downside to growth that arrives as a by-product. Each human, over a lifetime, consumes a staggering quantity of resources. It is no surprise that the greatest step I can take to reduce my carbon footprint – even including abandoning my car and air travel while adopting a plant-based diet – is to have fewer children. Larger populations mean increased consumption of water, energy, materials, and food – all demands on nature that manifest as a sad litany of extinction, pollution, waste, climate change, rapidly spreading pandemics, depletion of fisheries, forests, water resources, soils, wilderness, and so on and so forth. Graphs of human numbers and these parameters move in lockstep. For specific data, such as the 2019 UN Sustainable Development Report, see internet resources.

Reducing population

Despite these alarming impacts on nature, the political reality is that economy ‘trumps’ environment. The poor must live, and, for the aspiring, economies are built on jobs and growth. The environment is hidden from city dwellers. The concern, as always, is that action will only be triggered when it is too late. Perhaps, paradoxically, wealth provides the means to tackle environmental problems. Much hope has been placed on the improvement of womens’ health, including their economic, educational, and political status in relation to men. High female status leads to low fertility and this is assisted by access to contraception and abortion. More draconian policies have been adopted, such as the one-child policy in China.

Demographic transition

Rapid and recent population growth was signalled by a ‘demographic transition’ when nations, over a period of several decades, shifted from high birth rates and high death rates, to lower rates of both. The global increase in urbanization, education, and material standard of living has seen birth rates fall worldwide. Over much of Europe and South America fertility rates are close to replacement levels while in Japan, S Korea, Russia and some nations of E and S Europe it is even lower. Even in S Asia, Africa, and the Middle East where it is still increasing, the rates are coming down.

All this can lead to a more relaxed, even complacent, attitude towards the future. Climate change is a reality check on environmental impact. Covid19 was treated across the world with different degrees of seriousness. Some countries, notably America and Brazil regarded the virus as either a minor problem and/or of less significance than the economic factors. Those countries that introduced tough rulings on masks, curfews, and lockdowns (Australia, New Zealand) achieved the most rapid results. The lesson is that we listen to the science and take programs of sustainable development seriously.


Total population is determined by three factors: mortality, fertility and net overseas migration (births, deaths, and immigration).

Baron von Mueller

Australian population and gender composition – 1788-2000

Based on 2004 data from the Australian Bureau of Statistics
Courtesy Wikimedia Commons

The Australian Bureau of Statistics publishes regular statistics on the Australian population. In 2013 the population was 23 million with a growth rate of 1.7% p.a., the fastest in the OECD (US=0.9, Britain 0.6, India 1.4, World 1.1). There was a net increase of 1048 people per day including both births (40%) and immigrants (60%). Immigration included 488, 100 permanent arrivals. The fertility rate (children/woman) was stable at 1.9.

 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. The population of 24 million in March 2016 is projected to grow to 39.7 million by 2055 (SoE 2016).

Historical background

There are several milestones in the history of Australian population growth, starting with the huge influx of people in the 1850s after the discovery of gold. After Federation in 1900 financial incentives were offered by the government to attract new settlers and this happened again after WWII to not only develop the economy but also to counter fears of invasion in a ‘populate or perish’ campaign from the north. In 1873 the Caucasian (and essentially British) emphasis on immigration, known as the ‘White Australia Policy’ came to an end. Then, with the end of the Vietnam War in 1975 there was a major influx of SE Asian migrants.

In 1900 the population was about 3.8 million, 1950 8.3 million, 2000 19.3 million, 2013 23 million.

In 2012 about half of the growth in net migration was from people with temporary visas; there were twice as many births (303,600) as deaths (149,100) and by 2028 there will be more people over 60 than under 20 placing a heavy burden on the health system.

Aboriginal population

At settlement in 1788 the combined population of New Holland (859 British; est. 350,000 to 750,000 Aboriginal) can be taken as being less than one million. Today in March 2012 it is about 22,855,000 with the Aboriginal numbers about the same as in 1788 after a major decline into the early twentieth century. Between 1960 and 2000 the rate of increase was about 300,000 a year. A 2008 ABS intermediate projection for 2050 was about 34 million.[3]

Fertility rate

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).


The Australian birthrate has fallen steadily since the 1960s probably as a result of more contraception and improved womens’ education and female participation in the workforce. Over the last 40 years increase in population has derived almost equally from natural increase and migration, although in the last few decades the racial mix of migrants, traditionally from Britain, Europe, and New Zealand, now comes mostly from Asia and Africa.

Mortality rate

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).

Life expectancy

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.

An Ageing population

As Australians are living longer so the age profile is changing. In 2012 the Australian Census showed that the median Australian age was 37, up 5 years in two decades. The working population is the economically productive component of society and there is concern that as the proportion of non-wage-earners increases economic growth will suffer and therefore the general standard of living. 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) Currently (2018) it is estimated that by 2022 retirement age adults (64) will outnumber children (to age 15).

Through the 20th century most of Australia’s population growth came from natural increase which contributed two-thirds of the rise in population between 1901 and 2001 according to the Home Affairs department. But over the past decade net overseas migration has overtaken births as the main component of population growth. It has also been the biggest contributor to growth in Australia’s working-age population since at least the 1980s.

Immigrants boost economic growth by increasing the percentage of people in the workforce. They also tend to be younger, better educated, and more motivated than the average resident according to the government’s 2015 Intergenerational Report. Detractors point to the increased demand on environmental resources and the costly need for re-training, complications and sometimes social conflict over differing social values and customs, and language and communication problems.


This account borrows heavily from the Australian State of Environment Report (2016).

Australia has one of the most geographically distinct population distributions of any country as 90% of people live in just 0.22% of the country’s land area (NSC 2013) creating regional pressures on the environment. Most of Australia’s population is in the east, south-east and south-west with most living in urban areas, notably the state capital cities. In June 2015, 15.9 million people—around two-thirds of Australia’s population—lived in a greater capital city, the cities experiencing 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.

Stabilizing population

A stable population number could be achieved with the current birthrate over time provided net migration does not exceed 70,000 p.a., with an outflow of 80,000 p.a. (an average for recent times) total intake would need to be less that 150,000 p.a.[1] Reducing the number of immigrants would be politically more expedient than regulating the birthrate. If net migration were zero from 1990, then the population would have stabilised by 2030.[1] Current policies would result in a population of 40 million in 2050 which would place a huge burden on the environment.


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).

In 1997 it was estimated Australia would reach a population of 25 million by the middle of this century. We are already there and our cities, schools and roads are not prepared for it.

Internal migration

Studies of city populations by the ABS published in 2018 also tell us about internal migration.


Australia’s largest city with a population of 5.1 million and growth rate of 2%. Population increase in the 2016-17 period was primarily due to overseas migration, accounted for about 85,000 of the increase of 102,000, significantly higher than Melbourne’s 64 per cent. The second most powerful driver, natural increase, saw the population swell by 35 000, compared to 36 000 in Melbourne. But internal migration sees Sydney much fewer. Melbourne had a net increase of 9,200 people, while Sydney recorded a net loss of 18,100, losing people to other parts of Australia mainly the remainder of New South Wales and Melbourne.


In the 2016-17 period Melbourne recorded its highest-ever net annual population increase of 125,000 to total 4.9 million Melburnians and a growth rate of 2.7%. The fastest-growing suburb in the country was Cranbourne East swelling by 27 per cent from 27,000 residents in 2016 to 34,000 in 2017. Melbourne’s population is now just 200,000 below that of Sydney which itself saw a record annual increase of more than 100,000 people. Overseas migration was Melbourne’s major source of people accounting for 64% of the growth, followed by a natural increase at 29%.
Internal migration boosted Melbourne by 9,200 people.


Brisbane recorded a 2% growth rate in the 2016-17 period, the city’s fastest growth since 2012-13 increasing the population by 48,000 to 2.4 million. Brisbane’s main source of growth was also overseas migration, accounting for 38 per cent of the population change. But unlike Sydney and Melbourne, the numbers are more evenly spread across the three measured components.
Natural increase accounted for 37 per cent of growth, while internal migration accounted for a quarter increase.

The area with the largest decline in population nationwide was recorded in Queensland, with Collinsville in the Bowen Basin, registering a drop of 5.1%.

The fastest and largest-growing area in Queensland in 2016-17 was Pimpama on the Gold Coast, which grew by 3,000 people, or 31%, largely due to internal migration.

Other capitals

The fourth-fastest-growing city was Canberra with an increase of 1.7% to 410,000. Growth in Western Australia’s Perth, population of just over 2 million, was low at just 1%, slightly behind Tasmania’s capital Hobart, which has 227,000 people, at 1.1%. At 0.7 per cent, Adelaide recorded its lowest growth rate since 2003-04. The South Australian capital now has a population of 1.3 million.

Growth was slowest in Darwin at 0.5%, taking the population there to 147,000.
Demographers said the new figures, combined with the breakdown of population drivers, were invaluable for infrastructure planning.

Different patterns of population growth in different regions can create different political issues.

A Big Australia?

What are the advantages and disadvantages of population growth in Australia?

Australian population projection to 2050

Australia population projection 2010 to 2050

From data in the Intergenerational Report, 2010 (p. 117)
Courtesy Wikimedia Commons

Do we need a ‘Big Australia’ to power economic growth and national prosperity aiming to increase the population to about 30 million by 2050? More people demand more resources and services – housing, clothes and do on which will certainly lead to a larger economy. On the downside it can increase unemployment levels, drive down wages and produce inadequate infrastructure of water, sewage and transport and if migration is of particular ethnic groups lead social tensions. However the commercial sector calls for more workers, the education sector for more overseas students.

Interpretation of the costs and benefits of a rapidly increasing population are contested in all three of the sustainability domains: environmentally, socially and economically.

Environmentally there seems a very clear and direct link between population number, resource use and environmental degradation with the view that this is a market failure that must be addressed, an economic link that needs decoupling. Economically population growth is perceived as self-evidently crucial to economic growth which contributes to Australia’s competitive international standing, national security, and individual well-being.

Ideally population should be stabilized at a level that can be sustainably supported (the view of Sustainable Population Australia) but how this can be measured in practical terms is highly controversial because some claim that Australia should have stopped growing decades ago while others point out Australia is a wealthy country with plenty of space to welcome more. What is the case for these two essentially opposing views?


The prevailing ethos in Australia has been to increase the population with reasons for this strategy being: to deter possible invaders; to populate the empty north; to provide labour for a developing economy; to accept, as a developed nation, our moral duty to accommodate more people in a crowded and conflicted world.

Historically Australia has been desperate for labour, providing highly reduced fares to encourage migrant labour, the ‘assisted passage’. However, population growth is not inevitable, it is a consequence of deliberate political decisions. Both the absolute numbers and ethnic composition of migrants has been a clear part of Australian policy from the earliest days.


Against population growth can placed the pressures of social-racial change, inadequate infrastructure, and environmental impacts to which it may be argued that with adequate water and energy policies combined with improved urban planning and infrastructure investment we would all be better off.


In 1945 both Australia and Sweden had populations of 7 million, since that time the Swedish population has increased to 9 million while over the same period the United Kingdom increased from about 50 million to 60 million. Australia has a population about the same as Sri Lanka which is an island smaller than Tasmania.

Three parameters often associated with economic growth, these being population growth, terms of trade (for Australia relating strongly to the mining boom) and labour productivity which has been declining for about a decade.


Regular updates on the state of the environment in relation to socio-economic factors are published in government State of Environment Reports. Population size relates strongly to food, water and waste management. Social challenges under increasing population relate to quality of life, food security and water access. A major current example is the Murray where in drought it has no flow in the lower reaches due to over-allocation to irrigation. As population numbers rise so do imports and the use of non-renewable resources, and there is reduced access to beaches, roads, bushland and public transport while matters to address include immigration and ageing

Underlying present increase in numbers is the assumption that population growth produces growth in the overall economy including per capita wealth: that economic growth is not only desirable but essential: that without population expansion economic growth will stall, placing pressure on company valuations and the performance of the sharemarket. However, this is not a foregone conclusion. In OECD countries there is a close relationship between stable population numbers and increasing wealth per person and it is slower in countries with growing populations. Some of the most affluent countries like Norway and Switzerland have stable populations. On the other hand there also seems to be a demographic transition in wealthy educated countries to dropping birth rates and slowing growth. It would seem that if there is any additional wealth then this must be perceived as adequately compensating these costs.

At a superficial level resource use can be compensated for by lifestyle choices and improved technology.

Commentary & sustainability analysis

A growing population requires economic growth if it is to maintain material living standards but this requires careful monitoring of the environmental, social, and economic impacts of increasing consumption and resource use. The perception that population growth is needed for economic growth has been questioned by some.

Globally in the 20th century, with the appropriation of more arable land, the improvement of crops, and the use of new technology associated with industrial agriculture, it has been possible to treble global food production in line with the increase in population. But as the global population increases from 6 billion in 2000, to 9 billion in 2050, food security can no longer be taken for granted or the impact of agriculture on both the environment and future resource availability.

With developing countries suffering poverty, and Western affluent countries suffering obesity, there is a clear need to rationalize global food distribution, but socially acceptable means for doing this have proved complicated. Australia, as a food exporter, should not be faced with difficulties here.

Australia’s population has more than quadrupled in the past century and the number of people is expected to reach 25 million by the end of 2018. If this trend continues the population will exceed 40 million within 40 years. We can expect an improvement in life expectancy. with male life expectancy reaching 92.1 years and female life expectancy reaching 93.6 years in 2060-61.
An increasing population places increasing demand on resources and the environment. But more people produce more goods and services and pay more taxes for government services. Some say Australia should have stopped growing decades ago. Others point out Australia is a wealthy country with plenty of space to welcome more residents.

The key parameters associated with the analysis of human population are: the number and impact of of births, deaths, migration, and the effects of the age structure.

Age Structure

The age structure indicates the number of people in each age group which can be important for planning infrastructure like roads, schools, childcare centres, and nursing homes – all of which are age-specific. We need some constancy if possible so that, for example, we don’t build new schools that soon need to be shut down.

For Australia it is only a matter of time before the old outnumber the young. Fertility rates have fallen steeply from a peak of 3.5 babies per woman in 1961 to 1.8 in 2016 — below the level needed to replenish the population. It’s been below this level since 1976.

This, combined with people living longer, means Australia is rapidly approaching a future in which people over 64 outnumber those under 15. We don’t know if this is problematic. Many retirees are healthy and leading productive lives minding children, travelling, and working part time. Australia will reach this demographic turning point within four to 23 years. If fertility falls further and Australia has fewer people arriving than leaving, the balance of old to young will start to reverse in 2022. With zero net immigration Australia would reach ‘peak child. At the momen when the population aged 14 or younger stops increasing. This could occur as early as next year if combined with low fertility, while high fertility would only delay this shift to 2025, according to ABS projections.

Over the 20th century, Australia’s population has become increasingly old. Ageing populations face a number of risks to living standards, including increased health and aged care costs, and a smaller share of working-age people to produce goods, services and wealth.

Reducing the population

Low birth rates, combined with few immigrants and high life expectancy, lead to a dwindling workforce and rapidly-aging population. This has happened in South Korea and Japan and once this trajectory has become established it is very difficult to turn around.

Australia has the unique population needs of regional and remote areas and the move from country to city as a result of uneven economic growth, so we must bear in mind not just the total number of people but also their geographic distribution. Sydney and Melbourne have traffic congestion but Adelaide is welcoming migrants.

Age structure is crucial to a country’s economic health because it determines the percentage of people available to work and this underpins living standards.
The higher the ratio of dependents (those younger than 15 or older than 64) to those of working-age (between 15 and 64 years) the higher the economic burden, since it means fewer people producing goods and services, and paying taxes.
As the last of the baby boomers retire, the economic burden will inevitably increase. But how fast depends largely on the number of overseas migrants.
Does Australia need immigrants?

Australia’s population growth through the 20th century came mostly via natural increase which contributed two-thirds of the rise in population between 1901 and 2001. But over the past decade immigration has overtaken births as the main component of population growth and it has maintained a working-age population since at least the 1980s it is a counterfoil to a naturally aging population by increasing the percentage of people in the workforce. Skilled migrants also tend to be younger, better educated, and more motivated than the average resident according to the 2015 Intergenerational Report. Being younger they also tend to have children thus also boosting the fertility rate.

This thinking prompts statement like that of politician Peter Dutton “I want to bring people in as young as possible, as highly skilled as possible so they’re paying taxes for longer, they’re contributing to Australian society and they’re helping build our nation.”

The ideal population number?

The ideal population size will depend on your individual values and preferences. Understandably many (?most) people will choose to improve their material conditions by supporting economic expansion i.e. ‘wages, jobs, economic growth’. This is familiar political territory.

As contended elsewhere on this web site we need to aim for sustainability with a careful balance of social, economic, and environmental factors.

This is not the place for political advocacy but by now it should be clear that this web site encourages a thoughtful approach to the future in making an honest assessment of what constitutes material sufficiency (an adequate living standard), to recognize the potential social problems of gross inequity both locally and globally, and to recognise that all our behaviour has environmental as well as social and economic consequences.

Historic population statistics, Population Age Structure, and projections are available from the Australian Bureau of Statistics.

Resources & consumption

To live is to consume: the challenge is to consume sustainably

Sustainability can be measured for any kind of biophysical resource and at on any scale (e.g. country, economic sector, institution, household) but perhaps the most basic unit is the individual. Each of us from the moment we are born consume resources either directly, as when we drink a glass of water, or indirectly as when we purchase a car we are, in effect, accepting responsibility for the energy, water and other resources that were needed for its construction. Over a lifetime each individual’s consumption of resources is staggering in its magnitude. For example, although in Australia we only use about 100 to 200 l of water a day directly for washing, drinking, cooking etc. we use about another 3,000 l/day embedded in the goods and services we use. If we live to 80 then this is equivalent to more than 93 GL of water, enough to fill over 37 Olympic swimming pools.

Even so the environment may be able to provide this huge volume of water without significant detrimental effects, but this example does make the point that from a sustainability perspective it would be extremely helpful to have the best possible quantitative measure of the social, economic and environmental impacts of our resource use, bearing in mind our own particular location and the particular circumstances of our resource use: a tall order but a scientific challenge and a worthy goal.

As a hunter-gatherer I would be immediately aware of the impact I was having on my food, water and material resources because I would see it. Modern global trade conceals these impacts. We often do not know the sources of many of the products we use let alone the resource demands involved in their manufacture. In an era of international trade a country that imports all its food exports the environmental problems involved in its provision – water-supply, land use and so on.

Environmental carrying capacity

Peoples’ views are strongly guided by their ideology and political preferences. Certainly it would help the environmental case if there were a clear-cut method of estimating how many people the Australian environment could support in terms of their resource demands but such a figure is elusive because it depends so much on lifestyles both actual and anticipated.

Australia does not have critical shortages of food or water, it seems that infrastructure problems are more urgent – a decline in efficiency of public transport, water delivery, sewage, gas and electricity. Sri Lanka is about the size of Tasmania and has the population of Australia.

Statistics published from the 2016 Census and the updated Estimated Resident Population for the 2015-2016 calendar year.

Major items included: Victorian population 6.244 million, a 2016 growth of 146,600 persons, a rate of 2.4% and a state record, larger than any other state or territory (NSW 116,400) and faster than any other state or territory (ACT 1.7%) and much higher than the national rate of 1.6%. The largest component of Victoria’s growth was Net Overseas Migration, accounting for an addition of 74,000 people. Net Interstate Migration was at record levels for a calendar year, contributing 18,000 to growth and natural increase accounted for an addition of 43,400, with 82,900 births and 39,500 deaths.

The Australian population on 31 Dec. 2016 was 24.386 million, an increase of 372,800 over the calendar year.

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10,000    –    0.002
8000    -    0.005
6000    –    0.011
4000    –    0.028
2000    –    0.072
1000    –    0.115

1      –    0.30
500     –    0.20   
1000      –    0.31      
1100      –    0.33      
1200      –    0.38      
1300      –    0.35      
1400    -
1500    -    0.43–0.50
1600    -    0.50–0.58
1700    -    0.60–0.68
1800    -    0.89–0.98
1900    -    1.56–1.71
2000    -    6.06–6.15
2100    -    c. 10–13   


Inc. C Asia as former USSR

YEAR       MILLIONS       %WP

1      –      34    -      15%

1000      –   40   –    15%

1500      –    78    –    18%

1600    –    112    –    20%

1700    –    127    –    21%

1820    –    224    –    21%

1913    –    498    –    28%

2000    –    742    –    13%

Courtesy - Wikipedia


  YEAR            MILLIONS

  1788              0.000859
  1800              0.005217
  1820              0.033,545
  1840              0.190,408
  1860              1.145,585
  1880              2.231,531
  1900              3.765,339
  1920              5.411,297
  1940              7.077,586
  1960              10.391,920
  1980              14.807,370
  2000              19.272,644
  2020          c. 27.000,000

ABS, 2008

CITY POPULATIONS (millions)[1]

           WEST                      EAST


2000 - New Yk/16.7          Tokyo/26.7
1900 - London/6.6            Tokyo/1.75
1800 - London/0.9            Beijing/1.1
1700 - London/0.6            Beijing/0.65
     + Constantinople
1600 - Const'ople/0.4       Beijing/0.7
1500 - Const'ople/0.1       Beijing/0.6
1400 - Cairo/0.125            Nanjing/0.5
1200 - Baghdad/0.25        Hangzhou/0.8
     + Cairo, + Const'ople
1000 - Cordoba/0.2          Kaifeng/1
800 -   Dam'cus/0.175      Chang'an/1
600 -  Const'ople/0.125    Chang-an/0.25
400 -  Rome/0.5                 Luoyang/0.15
200 -  Rome/0.8                 Luoyang/0.12


1 -      Rome/1                     Chang-an/0.5
200 -  Alex'ia/0.3                Linzi/0.125
500 -  Babylon/0.15           Luoyang/0.08
           + Linzi
1000 - Susa/0.025             Qi/0.035
1200 - Bab'n/0.08              Anyang/0.05
           + Thebes
1500 - Uruk/0.075         Zhengzhou/0.035
          + Thebes                             + Yanshi
<2000 - Memphis/0.06     Erlitou/0.015
3000 - Uruk/0.045             Dadiwan/0.002
4000 - Uruk/0.005             ?Xipo/<0.001
          +Tell Brak                        +?Dadiwan/


Date (CE)          City          Population
M = millions, T = thousands

0-450          Rome                     1.6M
450-700      Constantinople    790T
700-804      Cordoba                160T
804-969      Constantinople    490T
969-1053     Cordoba               370T
1053-1169   Constantinople   246T
1169-1248   Kiev                      200T
1248-1353   Paris                     220T
1353-1391   Cadiz                      90T
1391-1765   Constantinople   710T
1765-1806   Vienna                  930T
1853-1885   London                1.2M
1885-1886   Paris                       2M
1885-1967   London                  8.6M
1967-2004   Moscow               12M
2004-2019   Istanbul                15M

Media gallery

Population, sustainability, and Malthus

CrashCourse World History – John Green – 2014 – 12:50


Top Tenz – 2017 – 8:31

15 LARGEST CROWDS in Human History

Top Fives – 2020 – 16:41

Top 15 Largest European cities in history (1 AD – 2019)

Rankings Hub – 2019 – 12:37

The History of Urbanization, 3700 BCE – 2000 CE

Max – 2016 – 3:20

Top 20 Most Populated Cities in The World 1500 to 2100 (History + Projection)

Animated Stats – 2019 – 6:30

Top 20 Country Urbanization History (1960-2017)

WawamuStats – 2019 – 3:08


First published on the internet – 1 March 2019
. . . substantive revision 28 July 2020
. . . revised 21 November 2020

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