By Dr Alec Thornton
UNSW @ Canberra

A global population of seven billion and counting has serious implications for how to feed our expanding human settlements. The UN forecasts that today's urban population of 3.2 billion will rise to nearly five billion by 2030, when three out of five people will be urban dwellers.

In 1800, three percent of the world's population lived in cities, and these settlements were quite self-sufficient in meeting the needs of the population. This century, more people live in urban areas than in rural areas (51 percent). Much of the urban population growth is occurring on the African and Asian continents. This will undoubtedly increase the number of cities with at least one million occupants, as well as ‘Megacities’, or metropolitan agglomerations of at least 10 million people. There are 21 Megacities in the world, but several of these have more than 20 million people; Tokyo has a population of more than 34 million. Developing regions will account for much of future urban growth over the next 25 years. Currently, one billion people now live in squatter settlements and shantytowns, and this number is expected to increase to two billion by 2030.

Australia is one of the world’s most urbanised countries -- 89 percent of the population live in cities and towns. Sydney and Melbourne have populations over four million; by 2030, these cities might each have a population of six million. Outside of Australia, modern, highly industrialised and heavily populated urban regions have public railways; which actually makes living outside of the city, in smaller towns and villages, an attractive alternative to suburbia, or settlements in exile. Local network of small-scale farms, in green zones between suburbs and in peripheral smaller town, could provide some of the food needs of urban populations. In parts of Europe and North America, these networks exist and are expanding as a community-supported agriculture model.

The ability of Australia to feed its own share of the global population is already challenged and will become even more so in the next 20 to 30 years. Australia already imports much of its food supply and this supply is vulnerable to global shocks in production and distribution. For example, drought in Russia, a grain exporting country, led to price increases here on food staples, such as bread.

The combined impacts of global warming, soil erosion, desertification, drought and population increase in Australia are significant challenges for this country, leading to continued loss of arable land, which makes up less than 6 percent of this country’s total land area. So forget about Australia becoming a ‘food bowl’ for its neighbours, as some commentators have suggested -- as it will likely be the other way around. Most of Australia’s soils are naturally infertile and shallow, requiring careful management and costly inputs to support and maintain modern, intensive farming.

Research on carbon emission offset trading schemes is starting to promote low-carbon agriculture, which includes urban and peri-urban agriculture, as a key, yet untapped, sector. Urban agriculture for food production and forestry is a potential strategy for carbon sequestration and food security, by minimising the ecological footprint of cities---where the bulk of the earth's resources are consumed and wasted.

As the Australian urban population expands, planners, developers and politicians will want to slow down suburban sprawl through increasing densities. This will require more extensive use of light rail, rainwater harvesting and local food production in public green spaces, rooftops and in the suburbs. This is the only way for Australia to future-proof its cities in an era of resource scarcity and population growth.


We’re predominantly a nation of urban dwellers. Only six percent of our total land mass is arable. Filling our food bowls in the future means looking closer to home for food sources, says human geographer Dr Alec Thornton.

See also:

"Forget about Australia becoming a ‘food bowl’ for its neighbours."