||Liu Y, Whitman WB. Metabolic, phylogenetic, and ecological diversity of the methanogenic archaea. Ann N Y Acad Sci. 2008 Mar1125:171-89 Table - link PubMed ID18378594
||Modified from Lowe (2) and Prather and Ehhalt (140)
||Tg=10^12 gramms. Methane deposits released by coal mining, petroleum drilling, and petrochemical production. This value range is 13-18 percent of total methane emissions. (Estimates of the relative contribution of methane emission from a source to the total global emissions of 600 Tg of CH4 per year).