By Faridat Salifu
Recycling food waste instead of dumping it in landfills could dramatically reduce greenhouse gas emissions from major agrifood economies, according to a new global study published in Nature Food.
The study, led by Zhengxia Dou, professor of agricultural systems at the University of Pennsylvania’s School of Veterinary Medicine, analyzed 91 field-based studies across 29 countries to assess the emissions impact of composting, anaerobic digestion, and refeeding food waste to animals.
Dou and her team found that countries like the United States, China, and the European Union which together generate massive volumes of food waste could achieve significant climate gains by diverting this waste from landfills to circular alternatives.
Food waste buried in landfills decomposes anaerobically and produces methane, a greenhouse gas that is over 80 times more potent than carbon dioxide over a 20-year period.
Dou described landfills as “biological amplifiers,” noting that simply burying food scraps contributes disproportionately to global warming due to methane leakage.
Under a hypothetical model where the U.S., EU, and China diverted all landfill-bound food waste equally to composting, anaerobic digestion, and refeed, the emissions savings would be substantial.
In the United States alone, the researchers estimate that such diversion could offset methane emissions equivalent to those produced by nearly 9 million dairy cows.
Refeeding food waste to animals emerged as one of the most resource-efficient solutions, offering additional benefits such as reduced demand for conventional livestock feed and lower pressure on land, fertilizer, and water use.
The study estimates that refeeding could free up more than 5% of China’s land currently used to grow maize and soybeans for animal feed, land that could be redirected toward food production or conservation.
Anaerobic digestion, which converts food waste into biogas, also presented major emissions savings, while composting helped preserve soil nutrients and organic matter.
The researchers concluded that all three recycling pathways are low-cost, field-tested, and capable of delivering rapid climate and resource-use benefits.
They urged governments, especially in high-waste economies, to adopt supportive policies and infrastructure investments to scale food waste recycling at national levels.
The findings also reinforce the need for public awareness, with Dou emphasizing that “everyone eats food, so everyone is a stakeholder in the system.”
She encouraged individuals to reduce food waste at home and called for collective responsibility across the agrifood chain.
The research aligns with global calls for a transition to circular economy models in food and agriculture as a means to address climate change, food insecurity, and environmental degradation.
