Global estimation of methane emissions from termites

Termite with symbiotic methanogen is one of the methane sources to the atmosphere. Global total emission rate from termite has been estimated using empirical relationships between land-use type or vegetation productivity and termite density and uncertain emission factors (emission per unit biomass per time). For example, in our previous study, we estimate the total emission from termite as 15 to 27 Tg CH4 yr-1. This study revisits the total amount and its uncertainty of termite methane emission. First, we gather observational data to clarify geographic distribution of termites and develop a climatic envelope reflecting the environmental limit mainly by low temperature. Second, we correct data about termite population density, biomass, and emission factors to estimate the range of variability. Finally, we use the termite properties and potential habitat map and a process-based terrestrial ecosystem model (VISIT) to estimate the global total methane emission rate from termites, leading to a refinement of our previous estimate and then the global methane budget.