A light, colorless, gaseous, inflammable hydrocarbon, CH4; marsh gas. It is the simplest of the aliphatic hydrocarbons. See Marsh gas, under Gas.
(CH4) A gas produced by the decay of organic matter. Has a strong odour, is quite flammable and poisonous.
(CH4). hydrocarbon that is a greenhouse gas with a global warming potential most recently estimated at 24.5. Methane is produced through anaerobic (without oxygen) decomposition of waste in landfills, animal digestion, decomposition of animal wastes, production and distribution of natural gas and oil, coal production , and incomplete fossil fuel combustion. The atmospheric concentration of methane has been shown to be increasing at a rate of about 0.6% per year and the concentration of about 1.7 parts per million by volume (ppmv) is more than twice its preindustrial value. However, the rate of increase of methane in the atmosphere may be stabilizing.