The UN Environment Programme (UNEP) said emissions from food loss and waste were about five times greater than those produced by the global aviation industry.
More than 1 billion meals are discarded every day, with households responsible for about 60% of the total.
Food buried in landfills decomposes without oxygen and releases methane, a greenhouse gas responsible for almost one-third of global warming.
Over 20 years, methane traps 86 times more heat than carbon dioxide, making rapid reductions important for slowing near-term warming.
Food waste also squanders the land, water and energy used to grow, process and transport produce that is never consumed.
The Food and Agriculture Organisation (FAO) estimates that 1.4 billion hectares, about 28% of the world’s agricultural land, are used to produce food that is ultimately discarded.
Agricultural expansion is also a major cause of deforestation, meaning food waste contributes indirectly to the destruction of forests that absorb carbon dioxide.
“At a time when the world is searching for practical ways to slow warming quickly, tackling food waste may be one of the most immediate and cost-effective climate solutions available,” UNEP Official Martin Krause said.
Methane remains in the atmosphere for less time than carbon dioxide, meaning lower emissions could produce climate benefits within decades.
However, FAO said there had been no meaningful progress in reducing food losses since 2015.
The world remains far from reaching the Sustainable Development Goal of halving food waste per person by 2030. “We have to move faster,” Krause said.
African countries are introducing measures to reduce methane emissions from discarded food.
Eleven governments have committed to integrating waste pickers into formal waste-management systems and training workers to separate and compost organic material.
Supported by the UNEP-convened Climate and Clean Air Coalition, the projects have established community composting sites, strengthened household waste separation and improved livelihoods.
Black soldier flies are also being used to process organic waste into useful products.
Specialised facilities in Malawi and Uganda are breeding the insects as part of waste-management systems operating across a growing number of communities.
–UN/ChannelAfrica–
