The population of our planet is projected to hit 9 billion by 2050. Providing food security for these people will be an unprecedented global challenge. A special issue of Science probes and examines the obstacles to reaching this goal, but also provides some promising solutions.

How do we increase food production to feed a larger and more affluent global population while not pushing humanity further beyond the Earth’s already strained planetary boundaries? This problem is fittingly described as a perfect storm by an international team of scientists in a recent special issue of the journal Science that focuses on the question of future food security. Obviously the path forward cannot rely on the strategies used to address food shortages in the past, namely bringing more land under agriculture and exploiting more fish in the oceans. Land available for agriculture is becoming limited and many fish stocks around the world are either overexploited or at their exploitation limits. Some of the strategies discussed in the several perspective pieces and reviews are:

1. Address yield gaps. Yield gap refers to the difference between realized and potential productivity of a farm. It could be minimized through better application of biotechnology and management techniques. A yield gap may also exist because of the high costs associated with inputs (such as fertilizer and water) or the low returns from increased production. This is part of the poverty trap, where the risks of investment are so high and the means to offset them are absent that not investing can often be the most rational decision for a farmer to take.

2. Cut waste. Approximately 30 to 40% of food in both the developed and developing worlds is lost to waste (see figure below). In developing countries most waste occurs at stages prior to the retail stages, for example due to lack of cold storage facilities. Investment in transport infrastructure would reduce the opportunities for spoilage, whereas better-functioning markets and the input of capital could minimize waste, by allowing the introduction of cold storage (though this has implications for greenhouse gas emissions). In developed countries, food waste occurs at the consumer level. Consumers throw away huge amounts of food, due to low prices that give no incentive to minimize waste at the household level. Reducing developed-country food waste is particularly challenging, as it is so closely linked to individual behavior and cultural attitudes toward food.

Makeup of total food waste in developed and developing countries. Retail, food service and home categories are lumped for developing countries (from Godfray et al 2010, Science 327)

3. Change diet. Considering that animals consume one-third of the worlds grain harvests, only provide 15% of the worlds calories and that the conversion efficiency of plant into animal matter is  around 10%, there seems to be a water-proof case that food security could be reached if the majority of people were vegetarians. However it’s more complicated than that. First, there is substantial variation in the production efficiency and environmental impact of the major classes of meat consumed by people. Furthermore, while sophisticated models suggest that per capita cereal consumption in developing nations could rise by 1.5% (enough grain to ease hunger for approximately 3.6 million malnourished children) if rich countries halve their meat consumption, these levels fall very short of the gains many expect from curbing meat consumption. One reason is that farmers in developed countries usually feed their livestock corn or soybeans. Thus, if meat production is slashed, demand for corn and soy drops and they become more affordable. In parts of Africa and Latin America where corn is a dietary staple, this is good news. But people in many developing countries, particularly in Asia, don't eat much corn; they eat rice and wheat and so falling corn and soy prices don't help them. A more controversial finding is that if consumers in developed countries replaced meat with pasta and bread, world wheat prices could rise and trigger malnutrition in developing countries that rely on wheat.

4. Expand, but transform aquaculture. Expansion of aquaculture could have real positive impacts but only if it is complimented with serious efforts to reduce negative externalities (such as antibiotics and organic effluents) and increase the efficiency of resource use. Gains in sustainability could come from concentrating on lower-trophic level species and in integrating aquatic and terrestrial food production, for example, by using waste from the land as food and nutrients.

Local success stories

What is encouraging about this special issue is the smattering of reports that focus on local success stories from around the world. For example, Richard Stone reports how telecommunication networks are having profound effects on farmers in developing countries. Instead of having to drive into town to find out the price rice is fetching, farmers in Embalam, India can now use cell phones to receive weather forecast, download current grain prices and get hints on how to use less seed and fertilizer. All while their harvests are increasing. And from Uganda, Gaia Vince tells a story of how microloans and local outreach work that connects farmers to national agriculture scientists has led some farmers to reach food security in areas where most farms are barren grounds. It is readily apparent that this is one of humanities huge challenges, a "perfect storm" that ranks alongside (and is interlinked with) the mitigation of climate change. Navigating through it will require a revolution in the social and natural sciences concerned with food production, as well as a breaking down of barriers between fields. The goal is no longer simply to maximize productivity, but to optimize across a far more complex landscape of production, environmental, and social justice outcomes.