FactSentinel

When food waste is buried in a landfill, it decomposes without access to oxygen, a process known as anaerobic decomposition. This environment is ideal for methane-producing microorganisms, which break down organic matter and release methane gas as a byproduct. Methane is a potent greenhouse gas, with a warming potential roughly 25 to 80 times greater than carbon dioxide over relevant timeframes, making landfills one of the largest human-caused sources of methane emissions globally, according to the U.S. Environmental Protection Agency and other environmental agencies.

Composting, by contrast, is an aerobic process that relies on oxygen exposure through regular turning or airflow management. This oxygen-rich environment supports different microbial communities that break down organic material into carbon dioxide and stable, nutrient-rich compost rather than methane. While composting does produce some emissions, they are overwhelmingly carbon dioxide rather than methane, and the climate impact is substantially lower. Studies from organizations like the EPA and various life-cycle assessments consistently show that diverting food waste from landfills to composting facilities can reduce associated methane emissions by significant margins, often cited in the range of 50 percent or more depending on the composting method used.

A common misconception is that all decomposition produces equal environmental harm, when in fact the presence or absence of oxygen fundamentally changes the chemical pathway and resulting emissions. Another misunderstanding is that landfill gas capture systems eliminate this problem entirely, but these systems are often incomplete or inconsistently implemented, allowing substantial methane to escape into the atmosphere regardless.