Potential of Clumped Isotopes in Constraining the Global Atmospheric Methane Budget

Abstract Atmospheric methane (CH 4 ) and its isotopic composition trends over the last decades are explained by various flux scenarios, from tropical wetland emission increases through to reductions in global hydroxyl (OH). In this study, we develop a modeling framework assess potential usefulness of clumped isotope measurements distinguish between main drivers change CH burden. We model interhemispheric differences 0.12‰ 0.38‰ seasonal cycles 0.02‰–0.04‰ 0.21‰–0.32‰ for Δ 13 3 D 12 2 , respectively, which is insignificant relative uncertainty that could eventually be made. show, however, specifically provide constraints understanding total source sink magnitudes, has not been possible with current sets observables. Changes OH concentration 10% developed across three result difference up 2‰ would observable given measurement limits. For type global‐scale analysis, show unlikely additional useful information. suggest an emphasis should now on developing methods make ambient air samples, followed sampling at clean Northern Southern Hemisphere sites, combined more accurate precise laboratory kinetic effects relevant atmospheric sinks.