By Michael McCord, Granite State News Collaborative

Just as New Hampshire has yet to run a comprehensive food waste characterization study, the same could be said nationally. A landmark 2023 EPA study laid out over three decades of research about the impact of food waste and its connection to methane emissions. The study is unique in part because, as the EPA acknowledges in its summary, “there is no other peer-reviewed national reference point for the amount of methane emissions attributable to food waste” in American municipal solid waste (MSW) landfills.

Some of the findings include:

• In 2020, food waste was responsible for approximately 55 million metric tons of CO2 equivalent emissions in MSW landfills across the country.

• An estimated 58 percent of the fugitive methane emissions (i.e., those released to the atmosphere) from MSW landfills are from landfilled food waste.

• An estimated 61 percent of methane generated by landfilled food waste is not captured by landfill gas collection systems and is released to the atmosphere. Because food waste decays relatively quickly, its emissions often occur before landfill gas collection systems are installed or expanded.

• While total methane emissions from MSW landfills are decreasing due to improvements in landfill gas collection systems, methane emissions from landfilled food waste are increasing.

• For every 1,000 tons (907 metric tons) of food waste landfilled, an estimated 34 metric tons of fugitive methane emissions (838 mmt CO2e) are released.

• Reducing landfilled food waste by 50 percent in 2015 could have decreased cumulative fugitive landfill methane emissions by approximately 77 million metric tons of CO2 equivalents (mmt CO2e) by 2020, compared to business as usual. 

(Carbon dioxide equivalent emissions, or CO2e, measures how much total greenhouse gas has been released into the atmosphere, which includes carbon dioxide, methane and nitrogen oxide. Methane, according to the EPA, is 28 times more potent than carbon dioxide in trapping heat in the atmosphere)

In layperson’s terms, as food waste in an anaerobic (covered, minimal air circulation) landfill slowly decomposes, it creates methane-producing bacteria that is either captured through landfill collection systems or naturally released into the atmosphere as a gas. The best illustration is the often-told story of the lettuce head taking 25 years to decompose while it produces methane all that time. By comparison, food waste in a compost bin can take as little as three weeks to fully decompose. 

These articles are being shared by partners in the Granite State News Collaborative. For more information, visitcollaborativenh.org.