Some offset projects consist of the combustion or containment of methane generated by farm animals, landfills or other industrial waste. Methane has a Global warming potential (GWP) 23 times that of CO2; when combusted, each molecule of methane is converted to one molecule of CO2, thus reducing the global warming effect by 96%. Methane can also be processed using an anaerobic digester which generates electricity or heat.

An example of a project using a anaerobic digester can be found in Chile where in December 2000, the largest pork production company in Chile, initiated a voluntary process to implement advanced waste management systems (anaerobic and aerobic digestion of hog manure), in order to reduce greenhouse gas (GHG) emissions.