Improved global wetland carbon isotopic signatures support post-2006 microbial methane emission increase

Abstract Atmospheric concentrations of methane, a powerful greenhouse gas, have strongly increased since 2007. Measurements stable carbon isotopes methane can constrain emissions if the isotopic compositions are known; however, from wetlands poorly constrained despite their importance. Here, we use process-based biogeochemistry model to calculate composition global wetland emissions. We estimate mean signature ?61.3 ± 0.7‰ and find that tropical enriched by ~11‰ relative boreal wetlands. Our shows improved resolution regional, latitudinal variations in simulation scenarios with suggest increases atmospheric 2007 attributable rising microbial findings substantially reduce uncertainty improve understanding budget.