How can methane be produced by inorganic processes inside Earth?

While methane is primarily associated with organic processes, such as the anaerobic decomposition of vegetable matter, some methane may be produced through inorganic (abiogenic) processes within Earth.12

The theory of inorganic formation suggests that Earth’s original carbon was derived from cosmic debris, such as carbonaceous chondrite meteorites, which contain hydrocarbons. It is hypothesized that these hydrocarbons may be continuously outgassing from within the planet, potentially accumulating as abiogenic gas deposits that never passed through an organic phase.1

However, it is important to note that significant accumulations of inorganic methane have yet to be discovered, and any such gas resulting from widespread outgassing would likely be too diffuse to be of commercial interest. While industrial methods like the Fischer-Tropsch reaction can convert carbon monoxide and hydrogen into hydrocarbons, this is a human-engineered process rather than a natural geological mechanism for methane production.13