Food waste isn't just a devastating misuse of natural resources, it's also a huge part of the world's carbon footprint, according to the United Nations Food and Agriculture Organization (FAO).
Every year, the world throws out about 1.3 billion tons of food -- a startling one-third of the food produced. And that creates a greenhouse gas footprint bigger than all countries, except for China and the U.S.
How? Because of the immense amounts of energy, water and chemicals used for agriculture and food production. The food supply chain produces about 3.3 billion tons of carbon a year.
That means 30 percent of the world's farmland -- about 3.5 billion acres -- is wasted.
And not counting seafood, wasting all that food costs about $750 billion a year, about the GDP of Switzerland, says FAO.
"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 FAO Director-General José Graziano da Silva. "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."
"Food wastage reduction would not only avoid pressure on scarce natural resources but also decrease the need to raise food production by 60 percent in order to meet the 2050 population demand," writes FAO in its report, "Food Wastage Footprint: Impacts on Natural Resources."
The UN study is the first to examine the impacts of global food waste from an environmental perspective, looking specifically at consequences for the climate, water and land use, and biodiversity.
Where waste occurs
The majority of food waste (54 percent) happens during and after food harvesting, particularly while it's handled and stored. The rest occurs during the processing, distribution and consumption stages.
In developed economies, such as the U.S., where up to 40 percent of all food is wasted, the issue is one of consumers buying too much and throwing away what they don't need. Elsewhere, in emerging and developing nations, the waste comes from farming inefficiencies and a lack of proper storage, reports FAO.
Asia (China, Japan, Korea) is a regional hot spot for vegetable waste and rice, the cultivation of which is extremely carbon-intensive. Meat waste is a big issue in Latin America, which accounts for 80 percent of the world's meat waste. Fruit and vegetable waste is problematic in Asia, Latin America and Europe.
How to solve the problem
The highest priority is to reduce crop losses through better farming practices, says FAO. Also important are re-use and recycling strategies that make it easier to donate surplus food to those that need it, and to divert foods not fit for human consumption to livestock.
Beyond these strategies, FAO recommends by-product recycling, anaerobic digestion and composting to recover energy and nutrients. These processes also minimize the amount of methane created by food rotting in landfills.
"UNEP and FAO have identified food waste and loss as a major opportunity for economies everywhere to assist in a transition towards a low carbon, resource efficient and inclusive Green Economy," says Achim Steiner, executive director for the UN Environment Program (UNEP). "Today's excellent report by FAO underlines the multiple benefits that can be realized -- in many cases through simple and thoughtful measures by, for example, households, retailers, restaurants, schools and businesses -- that can contribute to environmental sustainability, economic improvements, food security and the realization of the UN Secretary General's Zero Hunger Challenge."
UNEP and FAO are founding partners of the Think Eat Save -- Reduce Your Foodprint campaign, launched this year to coordinate worldwide efforts to cut food waste.