Example
Suitable food and garden waste can become a soil amendment.
The catch
Poor aeration or management can create methane and other emissions.
Related terms
Methane, Anaerobic decomposition, Anaerobic digestion, Biogas, Biomethane, Destruction efficiency
In more depth
Composting, explained.
Composting's main climate benefit is what it avoids. Food and garden waste that rots in a landfill produces methane, while a well-turned compost heap or windrow keeps oxygen in the mix and releases mostly CO₂ that plants absorbed recently. That makes it a simple route for organic waste diversion, especially where anaerobic digestion, which also recovers energy, is unavailable.
Compost returns nutrients and improves soil structure, and it can add to soil carbon, though that store is modest and reversible. Labels need care. Packaging marked compostable often needs the sustained heat of an industrial facility and may barely change in a garden bin.