ROME – Global food waste amounts to 1.3 billion tonnes per year and is causing economic losses as well as environmental harm, according to a new report from the Food and Agriculture Organization of the United Nations. Food waste accounts for an estimated $750 billion annually in direct economic consequences for producers, consumes a significant volume of water and is responsible for an estimated release of 3.3 billion tonnes of greenhouse gases.

“All of us – farmers and fishers; food processors and supermarkets; local and national governments; individual consumers – must make changes at every link of the human food chain to prevent food wastage from happening in the first place, and re-use or recycle it when we can’t,” said José Graziano da Silva, director-general of the F.A.O. “We simply cannot allow one-third of all the food we produce to go to waste or be lost because of inappropriate practices, when 870 million people go hungry every day.”

The report highlights the segments of the supply chain where food waste occurs. For example, 54% of global food waste occurs during production, post-harvest handling and storage. Forty-six per cent happens at the processing, distribution and consumption stages.

The F.A.O. said developing countries suffer more food losses during agricultural production, while food waste at the retail and consumer level tends to be higher in middle- and high-income regions — where it accounts for 31% to 39% of total waste — than in low-income regions where the range is 4% to 16%.

“Hot spots” identified in the report include rice production, meat production and fruit. Waste of cereals in Asia is a significant problem, the F.A.O. said, with major impacts on carbon emissions and water and land use. Rice’s profile is particularly noticeable, given its high methane emissions combined with a large level of wastage.

While meat waste volumes in all world regions is comparatively low, the global meat business generates a substantial impact on the environment in terms of land occupation and carbon footprint, especially in high-income countries and Latin America, which in combination account for 80% of all meat waste. Excluding Latin America, high-income regions are responsible for about 67% of all meat wastage, according to the report.

Fruit was identified as a hot spot because of the amount of water wasted during production, and vegetable waste in Asia, Latin America and Europe was cited because of the large carbon footprint during production.

The F.A.O. said a combination of consumer behavior and a lack of communication through the food production supply chain underlie the higher levels of food waste in higher income regions. Consumers fail to plan their shopping, over-purchase, or over-react to “best-before-dates,” while product quality and aesthetic standards lead retailers to reject large amounts of edible food.

In developing countries significant post-harvest losses in the early part of the supply chain are a key problem, occurring as a result of financial and structural limitations in harvesting techniques and storage and transport infrastructure, combined with climatic conditions favorable to food spoilage, according to the F.A.O.

The report makes three recommendations for reducing the amount of global food waste, starting with better balancing production of products with demand. There is vast room, the F.A.O. said, for improving communication between suppliers and retailers to match demand and supply. Such communication may reduce the number of producers who produce a product but leave it rotting in the field for lack of a market to sell it. Supermarkets also may stand to improve their ordering process in an effort to reduce the number of unsalable products in producer’s hands.

In developed countries, the report said more environmentally-minded food retailing is needed. The F.A.O. recommends retailers move away from the practice of displaying large quantities of food, which are perceived as contributing to increased sales, or discarding food when it starts to approach the end of its shelf life. Rejection of food products on the basis of aesthetic or safety concerns was identified as a major cause of food losses and waste. In some cases, farmers discard 20% to 40% of fresh produce because it doesn't meet a retailer’s cosmetic specifications.

In the event of a food surplus, the F.A.O. recommends re-use within the human food chain – finding secondary markets or donating extra food to feed vulnerable members of society – represents the best option. If the food is not fit for human consumption, the next best option is to divert it for livestock feed, conserving resources that would otherwise be used to produce commercial feedstuff.

Finally, the F.A.O. noted that while re-use is not possible, recycling and recovery should be pursued. For example, the report said, byproduct recycling, anaerobic digestion, compositing, and incineration with energy recovery allow energy and nutrients to be recovered from food waste, representing a significant advantage over dumping it in landfills, because uneaten food that ends up rotting in landfills is a source of methane, which is a particularly harmful greenhouse gas.