The United Nations estimates that by 2050 there will be 9.7 billion people on the planet, up from 7.1 billion today. That's a lot of mouths to feed, especially when you consider that industrial agriculture is already putting the planet under stress from erosion, carbon emissions, chemical pollution – and loss of natural biodiversity.

The good news, according to a study released this week, is that there are many ways to provide enough food for a population approaching 10 billion – and still keep our remaining forests intact.

"There has been an argument that there would be a trade-off between feeding people and protecting the forests," lead author Karlheiz Erb, told DW. "The study shows that from a technical perspective many options are feasible – even without drastic changes to our diet."

Still, we can't have our cake and eat it. A balance has to found between the kind of farming methods we want to use, preserving natural habitats, and our daily diet.

Meat – or the environment

Predictably, the study found that how much meat we eat is a huge factor. If humankind gave up animal products altogether and went vegan, we'd actually need less space for farming in 2050 than we did in 2000.

If we keep eating meat as we do today, we'll need over 50 percent more cropland than we use today.

The study worked largely from projections of food demand drawn up by the US Food and Agriculture Organization, which assume strong intensification of agriculture. But it also looked at scenarios for lower crop yields – either as a result of a shift toward less intensive methods, such as organic farming – or as a result of climate change impacts that might reduce productivity.

"If we also see we have a strong surge in vegetarian – or even vegan diets – even at the have low yield levels, we can have feasible scenarios, because the demand is not so high," Erb said.

Business as usual?

Erb says that "business as usual" scenarios for food availability are possible. But he admits that even aside from the ecological costs they entail, there is also the question of whether they are desirable.

Typical western diets, heavy on meat and processed foods, aren't healthy. At the same time, one in nine people around the world "do not have enough food to lead a healthy active life," according to the World Food Program.

From this perspective, the question is not so much whether we can maintain the status quo as the population grows, but how we can find better ways of feeding the world – and fast.

Jose Luis Vivero Pol is a research fellow on food governance at the Catholic University of Louvain, Belgium. He arguesthat as one of the most fundamental necessities for life, food should be seen as a commons – with basic nutrition guaranteed in the same way many countries guarantee access to education and healthcare.

Waste not, want not

He argues that the challenge is not find ways of increasing food production – we already produce enough to feed close to nine billion people. But we waste almost a third of that.

"Because food is so, so cheap we don't care if we waste a third – it's still profitable," Vivero told DW. "That would be impossible in any other industrial production chain."

Vivero blames the "commodification" of food – the imperative to produce as much food as possible, as cheaply as possible – for a culture that takes food for granted. In the industrialised West, we assume we can eat meat as often as we like and think little of chucking a huge share of what we buy in the bin.

Vivero believes that when individual consumers make choices that have such a negative impact on others, the state needs to step in – for example by diverting the huge subsidies given to industrial farming to more sustainable practices, and by taxing or limiting meat sales.

Grassroots change

The American and European governments have little appetite for such intervention. But around the world, people are beginning to think differently about food.

"Obviously, to have a majority of agriculture turn organic would mean a huge shift," says Sören Köpke, editor of the academic journal Food for the Future, "Decentralizing food production, splitting it up into smaller units into smaller units again like it was for centuries – I don't seen this kind of political change coming very soon. What I see is grassroots movements trying to change agriculture from the bottom up."

Vivero points to "urban hipsters" getting involved in farmers' markets, community gardens and food sharing fairs, as well indigenous communities that produce and share food in ways that aren't mediated by markets.

A choice for the future

Erb stresses that his study was not about food security in general, but about ensuring that we are able to grow enough food, given current levels of consumption. It also makes no assessment of which scenarios might be preferable, in terms of environmental or social impact.

Even so, the results could be interpreted as offering humankind a choice – between preserving ecosystems and human health – or food production systems that are unhealthy for people and the planet.

"Population growth can be seen as kind of a smokescreen," Köpke says. "The inequalities in place in the capitalist system are much more important than population growth."