hydrocarbon gas emission process methane gas emission process A hydrocarbon gas emission process during which a portion of methane gas is transported into the atmosphere. http://orcid.org/0000-0002-3410-4655 envoPolar Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from livestock and other agricultural practices and by the decay of organic waste in municipal solid waste landfills.