Landfills are engineered to bury waste tightly, creating exactly the conditions these microbes prefer. Food scraps, grass clippings, and branches are especially methane-rich compared with paper or wood, which is why this waste stream has drawn the attention of climate researchers.

What does "diversion" mean in practice?

Keeping food out of landfills does not mean it disappears. Three practical routes exist:

• Composting, where microbes break down scraps in the presence of oxygen and produce a soil amendment rather than methane.
• Anaerobic digestion, a controlled industrial process that captures methane from decomposing waste and burns it for electricity or heat.
• Source reduction, which means simply wasting less food in the first place.

Each route has tradeoffs. Backyard composting handles small volumes but struggles with meat, dairy, and oily foods. Municipal programs require trucks, drop-off sites, and public education. Digesters need capital investment and a steady feedstock, but they recover energy and avoid the landfill entirely.

How large is the 6% figure?

The 6% figure represents the potential methane reduction if all food and yard waste in the U.S. were diverted from landfills. It does not account for methane that may be released during composting or digestion, though those emissions are typically far lower than open-landfill conditions.

The estimate also assumes the U.S. could capture or process all organic waste — a logistical leap that no current policy approaches. A more realistic scenario, with partial diversion, would yield a smaller cut. Researchers frame 6% as an upper bound rather than an immediate target.

What are the limitations?

The finding is a modeling exercise, not a measurement of an active program. It does not quantify the cost of building composting infrastructure at national scale, nor does it address how households would change their habits.

Methane from oil and gas operations, livestock, and coal mines each contributes a larger share of the U.S. total, and those sources face different policy tools. Broader adoption of food-waste diversion would depend on local government capacity, funding, and public participation — variables no single number can capture.

Why does the number still matter?

Even with those caveats, the 6% figure gives policymakers an anchor. Methane has drawn renewed attention as a near-term climate lever, and food waste is one of the few sources where individual behavior, municipal policy, and industrial technology all intersect.

A kitchen scrap tossed into a landfill becomes part of a climate problem far larger than the trash can it lands in. Diverting it could be one of the simpler pieces of the methane puzzle — provided the infrastructure and habits line up.