Gasi rechisikigo, yakanyanya kuumbwa methane ine huremu hwema molecular 16, yakareruka kupfuura mhepo, iyo ine huremu hwemamorekuru hunosvika 29 nekuda kwezvakanyanya zvinoumba nitrogen uye oksijeni. Musiyano uyu wehuremu hwemamorekuru unoita kuti gasi rechisikigo riite shoma uye rinoita kuti rikwire munzvimbo yemhepo.