2.4 billion extra people, no more land: how will we feed the world in 2050?

The finite resources of the Earth will be be stretched as never before in the coming 40 years because of the unprecedented challenge of feeding the world in 2050, leading scientists have concluded in a report to be published next week.

Food production will have to increase by between 70 and 100 per cent, while the area of land given over to agriculture will remain static, or even decrease as a result of land degradation and climate change. Meanwhile the global population is expected to rise from 6.8 billion at present to about 9.2 billion by mid-century.

The Government-appointed advisers are expected to warn that "business as usual" in terms of food production is not an option if mass famine is to be avoided, and to refer to the need for a second "green revolution", following the one that helped to feed the extra 3 billion people who have been added to the global population over the past 50 years.

In the hard-hitting report, commissioned by the Department of Business, Innovation and Skills, the scientists will warn that the era of cheap food is over, and that governments around the world must prepare to follow the leads of China and Brazil by investing heavily in research and the development of new agricultural techniques and practices.

The authors of the Foresight report, Global Food and Farming Futures, will argue that to boost crop yields to the level needed to provide enough food for all by 2050 every scientific tool must be considered, including the controversial use of genetically modified (GM) crops – which have been largely rejected by British consumers.

They will suggest that the public needs to be better convinced of the benefits of GM food, and will advocate an educational campaign to improve acceptance of what they see as one of a set of innovative technologies that can contribute to and improve food security in the coming century. "We say very clearly that we should not tie our hands behind our backs by dismissing GM," said one of the report's authors.

The scientists are expected to recommend that GM technology should be shifted away from the private sector to one that is mostly funded and deployed by publicly funded bodies, in order to avoid what is seen as the stranglehold of large agribusiness companies such as Monsanto.

To combat the huge amounts of food waste – up to 40 per cent of food bought in developed countries ends up being thrown away – the scientists are also expected to recommend changes to legislation covering "sell by" dates. Relaxing these restrictions, the scientists will argue, could help to reduce the enormous amount of edible food discarded by British consumers.

They also want to see a massive injection of funds into agricultural research, to reverse the decline of public funding in recent decades as a result of successive governments viewing agriculture as low priority in times when food was cheap and plentiful.

The report's conclusions and recommendations mirror closely those of a French study published last week on how to feed the world in 2050. The report by two leading research institutes, in a project entitled Agrimonde, found that nothing short of a food revolution is needed to avoid mass famine. "A few years ago the world and Europe was producing too much food, and food was getting cheaper and cheaper. Now world agriculture lies at the heart of major worldwide challenges, and [this report] tells us why business as usual is not an option," said Patrick Caron, one of the Agrimonde authors.

Like the UK's Foresight report, the French study found there is no overwhelming obstacle to feeding a global population of 9.2 billion people, provided food yields are boosted, waste is cut both after harvesting and in the kitchen, and food distribution is improved.

However, the French study also suggested there are two possible routes to feeding the world. One involves unsustainable improvements in crop yields which do not take into account the detrimental impact on the environment, while the other is a sustainable route which will involve people in the developed world consuming less and decreasing their average food intake.

"The world can properly feed 9 billion people by 2050, but it will depend on what's on our plates and what is wasted from our plates," said Sandrine Paillard, who contributed to the Agrimonde study.

People in the developed world could decrease their food consumption – as measured by daily energy intake – by an average of 25 per cent and still have a healthy diet, she said.

Case Study: Chinese family who exemplify the problem

The Chinese exemplify the trend in the developing world for people to move from the country, and a largely vegetarian diet, to the city, where they eat more meat and fish.

Han Xiaotao, 29, and his wife Cui Xiaona, 28, are migrant workers from the small town of Xingtai in Hebei province. They have moved to run a butcher stall at a market in Haidian in western Beijing.

"Life in the countryside is much simpler," said Mr Han. "There we ate simple food like noodles, mantou [steamed bread] and corn, and supplied vegetables for the family from our courtyard, things like cucumber, tomatoes, potatoes, cabbage and green onions. When I was young we had only cabbage every day."

They now regularly enjoy pork, beef and chicken. "My wife likes fish!" said Mr Han. "In the countryside, it is too difficult to buy fish. But here it is so easy."

New 'green revolution' must boost yields yet preserve the environment

The principle problem of feeding the world in 2050, when the global population is expected to peak at about 9.2 billion people, is to increase food production without extending the area of land set aside for agriculture.

Scientists believe the only way this can be done is by bridging the "yield gap" between what a plot of land should be able to produce, with the best techniques and practices, and the actual amount of food produced.

This is seen as one of the main goals of agricultural research over coming decades. The problem will be exacerbated by the need to increase yields sustainably without damaging the environment either through soil degradation or water pollution.

During the "green revolution" of the 1960s and 1970s crop yields were increased significantly through modern crop-breeding techniques and the use of agro-chemicals, such as fertilisers and pesticides. Over the past 50 years only about 9 per cent of extra land globally has been brought into agricultural production, yet some cereal crop yields have almost doubled.

However this past increase is unlikely to continue into the future without radical changes to the way food is produced, stored and transported. For a start, some agricultural land that was productive in the past has been lost to urban development. Other land has suffered desertification, soil degradation or salinisation caused by over-irrigation.

Scientists estimate, for instance, that in parts of southeast Asia where irrigation is available, the average maximum rice yields that should be possible are about 8.5 tonnes per hectare. But actual average yields are only 60 per cent of this figure.

Maintaining a high yield requires continual innovation in order to control weeds, diseases, insects and other pests that can develop resistance to different control measures, and to counter crop diseases that emerge in areas previously free of them.

Scientists believe that crop yields should be increased by "sustainable intensification". This means improving the efficiency of food production without incurring the negative side effects on the environment seen in the first green revolution, when intensive farming led to higher yields but at the cost of environmental degradation.

Prosperity brings fresh challenges

A growing human population and a transformation in the diet of billions of people in the coming 40 years will place unprecedented pressure on food production, which will need a second "green revolution" to match the one that has helped to feed the world over the past half century.

The current population of around 6.8 billion people is expected to grow to just over 9 billion by 2050, and there will be a continuing mass migration of people from the countryside into cities. This urbanisation in developing nations will be coupled with an increase in wealth and a shift towards diets rich in meat and dairy produce, which require more farmland to produce compared to more vegetarian diets.

Although without immigration Europe's population is expected to decline by 2050, Africa's will double, China's will peak in about 2030, and India will overtake China as the world's most populous country by around 2020. The increased wealth and urbanisation of India and China in particular will place additional burdens on global food production.

Scientists have documented three phases of food consumption countries pass through as they develop. The first is known as the expansion phase, when undernourished people begin to eat more poor-quality food, mainly grain, roots, tubers and pulses. The second phase is substitution, when these staples are replaced by more energy-rich foods such as meat, dairy and vegetable oils.

The end result is the nutrition phase, when the increased production of high-energy foods requires more resources, for instance when grain is fed to livestock – this requires more land and agricultural inputs such as the use of pesticides and fertilisers.

Some developing countries experience all three phases at once, resulting in the double burden of undernutrition among the poorer classes, even as overnutrition and obesity emerge as problems in other sectors of their societies.