Methane is a potent greenhouse gas. It eventually decays into carbon dioxide, but that takes decades. Thus, if we want to minimize global warming in this century, we had better care about methane production.
Methane is a product of biomass rotting. Thus, biochar can reduce methane production as well as CO2 production, relative to letting the biomass decay through natural processes.
Methane is also a product of incomplete combustion. Thus, biochar, if done wrong, could lose much of its short-term greenhouse gas benefit.
