Methane is a colorless odorless gas. It is also known as marsh gas or methyl hydride. It is easily ignited. The vapors are lighter than air. Under prolonged exposure to fire or intense heat the containers may rupture violently and rocket.
Methane is the main hydrocarbon component of natural gas, which is a type of fossil fuel. At typical temperatures and pressures it is a gas and makes up around 95% of the content of LNG, and around 80-90% of natural gas.
Methane is also a greenhouse gas, like carbon dioxide (CO2). It has a shorter atmospheric lifetime than CO2, at 12 years, but this is "balanced" by the fact that it is more effective at trapping heat than CO2, as methane has a GWP (Global warming potential) of 21.
Methane combustion provides a significant fraction of the world's primary energy, and is used for home heating, cooking food, heating water, and electrical generation. It can even provide energy for transportation.
However, this means that it is also a significant contributor to climate change since this methane produces a fair amount of the carbon dioxide that humans emit into the atmosphere.
Methane’s atmospheric lifetime - around 12 years - is much shorter than that of carbon dioxide, which lingers for more than a century. But methane is, per unit, more than 20 times as potent as CO2 as a greenhouse gas.
That means that over a 20-year period, the global-warming potential of one tonne of atmospheric methane is similar to that of around 85 tonnes of CO2, according to the Intergovernmental Panel on Climate Change.