Photograph by Bob Sacha, National Geographic

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Pigs are slaughtered in Sichuan Province, China. 

Photograph by Bob Sacha, National Geographic

Sustainable Earth: Food

For Rio+20 leaders seek the right balance of technology and policy to feed a growing world more sustainably.

In a world that produces more food than ever before, far too many people will still go to bed hungry tonight.

"Food security—hunger—is a huge problem," said Shenggen Fan, director general of the International Food Policy Research Institute. "Almost a billion people are suffering from undernourishment. They simply don't have enough to eat.

"And more than two billion people are suffering from nutritional deficiencies, the lack of things like iron, zinc, and vitamin A. This 'hidden hunger' can cause great damage to people's health and to their productive lives because economic growth really suffers with undernourishment," said Fan.

When the United Nations Conference on Sustainable Development (Rio+20) will be held in Brazil from June 20 to 22, Fan stressed, "poor people's access to food has to be at the center of the discussion."

Of course, the main sources of human food include farms and fisheries. But both of these sources are being exploited unsustainably.

Down on the Farm

More than 40 percent of the world's population is employed in agriculture—more than in any other sector. In developing countries, tiny smallholder farms provide up to 80 percent of the total food supply. These rural, poor households are most vulnerable to variable weather and climate.

"Around half of these small farmers in the developing world are either self-sufficient, just eating what they produce, or they are net food buyers rather than net food sellers," Fan said. "So the first priority for them is to grow more healthful, nutritious food to feed themselves. They can't just produce rice. They need a more diversified production."

Since the 1900s, a staggering 75 percent of the world's total crop diversity has disappeared from farmers' fields. Restoring crop diversity can help small farmers achieve a more varied and nutritious diet, while getting greater productivity from the land with fewer inputs of water, fertilizer, and energy. This is partly because breaking up monoculture tends to reduce concentration of pests, and certain plant combinations can even serve as "biological controls" by repelling pests. A diversity of crops also tends to make a farm better able to weather changes in rainfall or temperature.

Fan touts the advance of new crop varieties like rice, corn, and sweet potatoes bred for the climates in which they're grown that can better tolerate troublesome pests or resist heat and drought. "We're looking at seeds that have higher nutritional value but [by requiring less human intervention] also cut down energy use and carbon emissions at the same time," Fan said. That's another important step toward sustainability for an industry that produces some 30 percent of all greenhouse gas emissions, and is among those most threatened with changes as the climate shifts.

But helping smallholder farmers feed their families is only an initial step, Fan stressed. "Eventually we must help many smallholders to graduate from subsistence farming so they can sell produce and provide educational opportunities for their children. We have to help them to earn money through food production," he said.

Fishing for Change

Fishing is another paramount source of human food; some three billion people count on marine species as their primary source of protein. Our oceans once seemed inexhaustible, but today the troubling impacts of overfishing are already being felt around the globe. If the seas are to nourish future generations they must be managed far more sustainably and protected from destructive threats like pollution. (Read more about fisheries in our oceans coverage of Rio+20.)

Earth's surging population is likely to make our food problems even more acute. It's projected that two billion more people will need to be fed by the year 2050, raising the specter of more food crises like the one that struck in 2007 and 2008. In those years, spiking demand led to rising grain prices, bad weather and poor harvests depleted supplies, and rising oil prices made it more expensive to grow food—and consequently to buy it.

Prices in some countries rose a staggering 75 percent from 2006 levels, and 115 million people joined the ranks of the chronically hungry, according to UN estimates. Developing nations bore the brunt of the disaster, particularly across Africa, and food riots and political unrest appeared around the world in places like Bangladesh, Haiti, Tajikistan, and Yemen. The poor, already the hungriest, are hardest hit by such events.

"Unfortunately, right now our way of using natural resources to feed the world and to promote the current living standards is not sustainable," Fan said. "Because water will be limited, energy will be more expensive, and the climate will be hotter. If we don't do something, I guarantee we'll have more food crises and more severe food crises."

For all the potential improvements in food production methods, Fan stressed, consumption patterns must also change.

"In the United States and Europe we are eating too much meat, and the consumption of meat really exhausts natural resources," he said. "Emerging economies like China and Brazil are picking up their meat consumption, and they account for perhaps 30 percent of the world's population. We simply don't have enough natural resources for them to follow our consumption patterns."

Fortunately, the path toward a more sustainable future can also provide more immediate help for those who need it most—and that's the challenge for Rio+20, Fan said.

"There are many opportunities where we can really promote policies, strategies, and investments that will improve food security and at the same time cut the use of natural resources by using them more efficiently," he said. "These goals aren't at cross-purposes; there is a synergy here we can use to our advantage."