A Huge Amount of Food is Wasted—And With It, Water, Energy, and Nutrition

Greenhouse gas emissions and food supply

About 70 percent of the water humans use globally is consumed by agriculture, and a full third of the greenhouse gas emissions we produce come from food production. Despite these massive costs, one-third to one-half of the world’s food supply—an estimated 1.3 billion tons—is simply lost or wasted every year. At the same time, 815 million people around the world remain undernourished. This results from a global food system that is simultaneously inefficient and over-productive and suggests that we are missing serious opportunities to reduce hunger, carbon emissions, and the stress on water resources.

In low- and middle-income countries, the chief problem is food loss—food that is produced but never makes it to consumers. Lower rates of farm mechanization, pesticide use, cold storage for produce, market access, and a greater susceptibility to extreme weather events mean that farmers are more likely to lose a portion of their crops, especially fruits and vegetables. In fact, farmers in Sub-Saharan Africa lose 35 percent of their crops during handling and storage, compared to 10 percent in North America. The pressure to avoid losses pushes farmers toward the production of cereal grains, which can be stored and transported more easily but are less nutritionally valuable than the fruits and vegetables which are much more susceptible to loss. This has negative consequences for food and nutrition security and contributes to the high rates of poverty among smallholder farmers.

In high-income countries, a highly efficient food production and processing system minimizes food losses. But a tremendous amount of the food successfully produced is simply wasted—unconsumed or discarded by consumers. People in North America and Europe waste about double the amount of food per capita compared to people in Sub-Saharan Africa and South and Southeast Asia. In wealthy nations, rates of food waste actually rise with the amount of food produced, perhaps because freedom from worry about scarcity encourages people to be less worried about waste. The inverse is true in the low- and middle-income countries, where rates of food waste are very low.

The scale of food loss and waste is galling, and unacceptable if we’re to meet the food security targets set by the Sustainable Development Goals. But more than food, waste on this scale also harms global water resource stability. Roughly a third of all water used for agriculture in North Africa and West and Central Asia—areas experiencing frequent water scarcity—is used to grow food that will ultimately be lost or wasted. In general, the food products most vulnerable to spoilage have highest water content. Food loss and waste thus carry significant waste of limited water resources. While water is technically an infinitely renewable resource, it is “consumed” by food production because the water that goes into growing and processing food is not available for other uses without investing significant amounts of energy to reclaim and clean it. The water that is lost in unconsumed food is, for practical purposes, wasted along with any energy cost that went into production.

Worse still, the carbon cost of producing that wasted food remains, and it is significant. Every year, about 3.3 billion tons of greenhouse gasses (7 percent of global emissions), and roughly half of the United States’ emissions, are created by producing food that is ultimately wasted. Simply reducing food waste would play a valuable role in the global struggle to rein in greenhouse gas emissions.

Because higher- and lower-income countries experience food losses in different parts of the supply chain, they require distinct responses. In the low- and middle-income countries, this means continued support for conditions that prevent spoilage and improve farmers’ ability to get their products to consumers. This includes improving cold storage chains for transporting perishable food products and improved market access for smallholder farmers to bring their products to consumers beyond the farm gate.

Food waste in high-income countries results from surplus and cultural choices. The desire for aesthetically perfect produce and the appearance of abundance in supermarkets results in a substantial amount of waste. Some reduction can be achieved by changing our behavior—only buying what we need and being sure to use it. But changes in the amount of food wasted by supermarkets will probably require extensive public pressure and perhaps legislation. France, for instance, is currently experimenting with a law that bans food waste by grocery stores. Enforced by steep fines, the rule requires grocers to donate nearly expired fare to food banks instead of throwing it away. This law not only helps significantly reduce the quantity of food going to landfills, but also directly reduces hunger in the country.

Reducing food loss and waste would go a long distance toward achieving food and nutrition security, and could be enough to prevent the need for agriculture to consume new sources of water and by extension the energy resources and greenhouse gas emissions that come with expanded water use. This is a clear case in which the solution to scarcity is not producing more, but seeking a tighter fit between what is produced and what is consumed.