Revisiting enteric methane emissions from domestic ruminants and their ?¹³C_CH4 source signature.

ABSTRACT: Accurate knowledge of ¹³C isotopic signature (?¹³C) of methane from each source is crucial for separating biogenic, fossil fuel and pyrogenic emissions in bottom-up and top-down methane budget. Livestock production is the largest anthropogenic source in the global methane budget, mostly from enteric fermentation of domestic ruminants. However, the global average, geographical distribution and temporal variations of the ?¹³C of enteric emissions are not well understood yet. Here, we provide a new estimation of C3-C4 diet composition of domestic ruminants (cattle, buffaloes, goats and sheep), a revised estimation of yearly enteric CH₄ emissions, and a new estimation for the evolution of its ?¹³C during the period 1961-2012. Compared to previous estimates, our results suggest a larger contribution of ruminants' enteric emissions to the increasing trend in global methane emissions between 2000 and 2012, and also a larger contribution to the observed decrease in the ?¹³C of atmospheric methane.

SUBMITTER: Chang J 

PROVIDER: S-EPMC6668425 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature