Solid waste degrades and releases methane. Any carbon in landfills are sequestered for as long as they remain in the landfill.

Landfilling (click here) is the most common waste management practice, and results in the release of methane from the anaerobic decomposition of organic materials. Methane is around 20 times more potent as a GHG than carbon dioxide. If the disposal of organic matter were decreased (for example by composting or combustion) it would be possible to reduce the amount of methane emissions. However, landfill methane is also a source of energy, and some landfi lls capture and use it for energy. In addition, many materials in landfi lls do not decompose fully, and the carbon that remains is sequestered in the landfi ll and not released into the atmosphere.