Quantifying Methane Emissions from Landfilled Food Waste
Methane, a powerful greenhouse gas, is emitted from landfills, resulting from the decaying of organic waste over time under anaerobic conditions. Municipal solid waste landfills are the third-largest source of methane emissions from human activities in the United States. Food waste comprises about 24 percent of municipal solid waste disposed of in landfills. Due to its quick decay rate, food waste in landfills is contributing to more methane emissions than any other landfilled materials. An estimated 58 percent of the fugitive methane emissions (i.e., those released to the atmosphere) from municipal solid waste landfills are from landfilled food waste.
![Illustration of a landfill with truck in foreground dumping food waste on the ground and superimposed in the corner a hand holding a plate with uneaten food being scraped into the food waste pile. Text at the bottom reads: In landfills, wasted food breaks down quickly, generating methane before landfill gas collection systems are in place. Wasted food causes 58% of methane emissions from landfills, but food waste only makes up about a quarter of the total waste in landfills EPA logo.](/system/files/styles/large/private/images/2023-10/kenny_landfill-methane.jpg?itok=-NO9BDj6)
To understand the impact food waste has on U.S. landfill greenhouse gas emissions, EPA developed the report, Quantifying Methane Emissions from Landfilled Food Waste, to estimate the quantity of methane emissions released into the atmosphere from decaying food waste in municipal solid waste landfills in the United States from 1990 to 2020. This analysis relied on existing, widely-used EPA models and data sources to compare the estimates of modeled methane emissions while examining factors that influence methane emissions. These factors include 1) total tonnage of landfilled food waste, 2) landfill characteristics, 3) food waste decay rate, 4) landfill gas collection systems installation and efficiency, and 5) amount of methane oxidized as the gas passes through the landfill cover material. This report is EPA’s first published estimate of annual methane emissions from landfilled food waste and the first peer-reviewed national reference point for the amount of methane emissions attributable to food waste in U.S. municipal solid waste landfills.
Results from the analysis revealed that while total emissions from municipal solid waste landfills are decreasing, methane emissions from landfilled food waste are increasing. Findings from this report illustrate the outsized impact landfilled food waste has on methane emissions. This data confirms that diverting food waste from landfills is an effective way to reduce methane emissions from municipal solid waste landfills.
![Photo of cars in a traffic jam with an illustration superimposed on the left hands side showing a hand holding a fork scraping food scraps into a garbage can. The EPA logo is in the bottom corner and a banner of text reads wasting food in the U.S. causes ghg emissions equivalent to those of more than 50M gas powered passenger vehicles.](/system/files/styles/large/private/images/2023-10/car-emissions_food-waste-life-cycle.jpg?itok=SJ6f1zZt)
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Report: Quantifying Methane Emissions from Landfilled Food Waste (pdf)
Landfill graphic: Landfill Methane from FW_EPA graphic 2023 (jpg)
Vehicle emissions graphic: Car emissions FW life cycle_EPA graphic 2023 (jpg)