The population capacity of Australia

Australia is one of the emptiest countries in the world. In fact, it is the 12th least densely populated country in the world, ranked alongside vast, empty territories such as Mongolia and Western Sahara.

However given that a significant area of Australia is arid desert, perhaps it has reached capacity, constrained by limited food production? Certainly, Small Australia advocates such as Dick Smith appear to think that Australia is under unsustainable population pressure, having made comments this week that Brisbane increasing its population to 4 million would be "complete madness".

Unfortunately for Dick, the food capacity figures don't support his view. Australia has by far the most food growing capacity per capita on earth. Real Population Density measures the number of people per kilometre of arable land. The chart below inverses Real Population Density and shows the amount of arable land per person - and Australia clearly has the largest by a significant margin.

The amount of arable land per capita, in square metres. Australia has by far the most arable land per resident. Other notable countries are highlighted in orange for comparison.

So we can see that Australia under-uses its arable land relative to other countries. But what could its population be if it matched the utilisation seen in other nations? The chart below shows what Australia's population could be.

If Australia had the Real Population Density seen in each of these nations, what would its population be?

If Australia fed as many people as the world average with its arable land, its population would be 152 million, around 7 times its current population, or just under half of the population of the United States.

Australia could allow its population to grow to 84 million, and it would match the utilisation of food growing capacity of the United States. If it grew to a massive 1.4 billion, it would only then be matching Japan and South Korea's real population density.

Of course there are multiple factors that can skew these figures. Food exports and imports will affect the figures at a national level. Other parameters include level of development and cultural differences; these will affect how food is used. Perhaps the fairest comparison is the United States - a nation of a similar geographical area, development level and culture - which indicates an Australian population of 84 million is entirely sustainable.

The 'Real Population Density' figures used here are derived from the 2005 CIA World Factbook.