Enough food can be produced to feed the world population until at least 2050 without the need to further clear forests for farmland, according to new research.

Key points: World's population expected to reach 9.6 billion by 2050

World's population expected to reach 9.6 billion by 2050 Study modelled 500 food supply scenarios based on no deforestation

Study modelled 500 food supply scenarios based on no deforestation Global veganism would allow the most options for food production

Global veganism would allow the most options for food production Global rich meat-based diet would allow the least options

Modelling published in Nature Communications today indicates diet will be the key to striking a successful balance between future global food needs and conservation goals.

With a shift toward vegetarianism and lower meat consumption, even lower-yield organic farming techniques could be used to generate enough food for the burgeoning world population, according to researchers at the Institute of Social Ecology at the Alpen-Adra University in Vienna.

"All the scenarios we have considered come with completely different ecological costs," said lead researcher Associate Professor Karl-Heinz Erb.

"Some of them have a high environmental pressure, and some of them have a lower environmental pressure, and we found that this is strongly determined by the diet."

The value of conserving natural ecosystems such as forests for climate, health and other biodiversity benefits is widely recognised. But this is challenged by the need to provide food and fuel for the rapidly increasing population.

Dr Erb and his colleagues set out to gauge the world's capacity to conserve existing forests while also providing enough food for the predicted 9.6 billion people who will live on Earth in 2050.

Diet key to environmental choice

The researchers created more than 500 food-supply scenarios based on no further deforestation and using regional forecasts for crop yields, agricultural area, livestock feed and human diet supplied by the UN's Food and Agriculture Organization (FAO).

In each case it was assumed that there would be free and open trade between all parts of the world.

After modelling the interactions between these factors, the research showed which scenarios were feasible — enabling enough food for the world — and which were not.

The researchers were surprised to find that more than half of the scenarios would create conditions in which food supply would be adequate without the need for further deforestation, but these options were strongly dependent on the world's dietary choices.

"Even a very rich diet in general terms would be possible," said Dr Erb. "But if we have a not so meat-rich diet, the options are much greater because we can avoid deforestation and at the same time we can also avoid high-intensity production levels."

In the unlikely situation that the entire world population adopted a vegan diet by 2050, the modelling found that 100 per cent of the scenarios would be feasible; global vegetarianism enabled success in 94 per cent; only about two-thirds are possible if the average diet remains the same as today; while the meat-based Western-style diet would work in only 15 per cent of the futures depicted.

All of the rich diet scenarios would require higher yield farming practices and significant cropland expansion into non-forested areas such as the world's natural grasslands.

Evidence for future debate

Before any decisions can be made on the basis of the analysis, Dr Erb cautioned it would be necessary to account for costs and benefits beyond those included in their models — among them the social and cultural benefits of farming and dietary changes.

"Our analysis provides only the technical basis for negotiations between different experts and stakeholders who should have a say about what is a good development and what is not a good development."

Australian sustainable agriculture specialist at the University of Melbourne, Professor Richard Eckard, agreed that many more factors needed to be considered before anyone begins to talk about reducing livestock numbers or increasing cropland.

"The reality of implementing some of these changes is quite limited," said Professor Eckard.

He pointed to the unsuitability of natural grasslands, such as the African Savanna, for cropping and the role livestock plays in providing the energy for farming in much of the developing world as two potentially important considerations not encompassed by the Australian modelling.