methane is a colorless, odourless gas, which is the most common hydrocarbon in the earth's atmosphere. It is of significance as a greenhouse gas responsible for global warming. About 20% of the total greenhouse effect is attributed to methane.
Methane, a greenhouse gas emitted to the atmosphere from ecological sources such as wetlands, manure deposits, rice paddies, municipal dumps, coal mines, leaks from gas wells, and pipelines.