Feeding our cities: counting the environmental cost

Humanity faces the daunting challenge of feeding nine billion people by 2050. Experts forecast that by then, about 70 per cent of the population will live in cities. As cities modernise their inhabitants become wealthier and diets diversify. Increasingly, growing urban populations rely on food produced elsewhere, while more and more land is required to meet food demand. The question is: will there inevitably be a time when these cities will not be able to source enough food?

The Human Ecology Research Group investigates the interactions between humans and their environments. One of its projects is to examine how food is sourced in three wealthy cities and their hinterlands: Canberra, Copenhagen (Denmark) and Tokyo (Japan). Dr Rob Dyball and David Dumaresq are collaborating with researchers from Copenhagen and Tokyo. “These capital cities and their regions have very different global, climatic and physical locations and socio-economic circumstances,” Dyball explains.

Dyball and Dumaresq are researching the trade-offs between food production and other land uses such as urban developments in the regions on which these cities depend. They have analysed data from 1965, 1980, 2000 and 2005 on the production, import and export of the three cities’ common food items such as apples, beef and wheat. According to their preliminary research, much of the food that their populations eat is not local produce. “In that sense, we can now say, from a human ecological perspective, that the ecosystem services city populations depend on are globally based,” says Dyball.

The research, so far, suggests that working out the earth’s capacity to support ever-growing urban populations is not a straightforward exercise. “Our research is not predictive or prescriptive, but is intended to help decision makers understand our global food system,” Dyball says.

The world’s population is growing and with it the percentage that is urbanised. As urban centres draw in rural populations, cities are increasingly dependent on an ever smaller number of people skilled in food production. Furthermore, as cities expand, smaller and less ecologically productive land areas are made available for farming. This means that global food supplies are vulnerable not only to social changes that affect land management, but also factors that affect the biological productivity of farmland such as climate change.

Dyball and Dumaresq’s research findings will be crucial in the development of food strategies that build the capacity of ever growing cities around the globe to adapt to this changing environment.