Definition

Methane (CH4) is a colourless, odourless, tasteless, non-toxic gas with a chemical composition of one carbon and four hydrogen atoms. It is a major component of natural gas. CH4 is highly flammable at very high concentrations of about 50,000 ppm. Methane acts as an asphyxiant at extremely high concentrations.

Methane is the second most important greenhouse gas. It is 28 times ( for 100 years timeframe) more potent than carbon dioxide at trapping the sun’s heat into the atmosphere. However, it has an atmospheric lifetime of around 12 years, much shorter than carbon dioxide.