Methane & Composting

Methane as a Greenhouse Gas

• Methane is a greenhouse gas produced from decomposing food and yard wastes when they break down in an anaerobic environment -- or an environment that lacks oxygen -- such as a landfill. Methane has 25 times the impact of carbon dioxide on climate change, According to Amherst College, and 13 percent of all greenhouse gases produced in the U.S. are related to food provisions.

Composting Reduces Landfill Methane Levels

• Food and yard wastes combined constitute between 28 and 39 percent of all solid municipal wastes in the country, depending on the area -- most of which could be composted, according to horticulture expert George W. Dickerson from New Mexico State University. Composting these materials in an oxygen-rich environment would significantly reduce methane emissions and acid-liquid drainage associated with landfills. Instituting comprehensive municipal composting systems would accomplish methane emission reduction. However, residents composting their own materials at home would further lessen the environmental impact of these wastes, as fuels and costs associated with transportation and industrial machinery would be eliminated.

Harvesting Methane From Food Wastes

• Since significant levels of methane are being produced in landfills and released into the atmosphere, scientists have researched how to harvest this gas as a useful resource instead. Methane produced from compostable materials in landfills can be captured and used as an energy source in place of fossil fuels. Anaerobic environments produce little heat and so the decomposition takes longer. However, once the decomposition is complete, the result of decomposing food and yard wastes in isolation from other wastes is the same: nutrient-rich humus. This humus can then be used by gardeners and farmers.

Compost and Other Greenhouse Gases

• Composting food and yard wastes would not only reduce methane emission levels at the landfill, it would reduce another greenhouse gas associated with agricultural fertilizer production -- carbon dioxide. Finished compost, or humus, is no different from the humus found naturally in forests; it just doesn't take as long to decompose. Compost, therefore, contains all the nutrients of naturally occurring humus, including nitrogen and phosphorus. To artificially produce one unit of nitrogen fertilizer, four units of carbon dioxide -- or CO2 -- are emitted. Making one unit of phosphorus fertilizer produces 1.75 units of CO2, according to Amherst College. Using compost, instead, would eliminate these emissions.