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Abstract

We provide a comprehensive review of the proxy data on the 13C/12C ratios and uncertainties of emissions of reactive carbonaceous compounds into the atmosphere, with a focus on CO sources. Based on an evaluated setup of the EMAC model, we derive the isotope-resolved dataset of its emission inventory for the 1997 2005 period. Additionally, we revisit the calculus required for the correct derivation of uncertainties associated with isotope ratios of emission fluxes. The resulting overall surface CO emission 13C in 2000 of (25.2±0.7)-up estimates and a factor of two less uncertain. In contrast to this, we find that uncertainties of the respective inverse modelling estimates a re substantially larger due to the correlated nature of their derivation. We reckon the 13C values of surface emissions of higher hydrocarbons being within 24 to 27 (uncertainty typically below ±1), with an exception of isoprene emissions 15 being close to 30. The isotope signature of ethane surface emission coincides with earlier estimates, however integrating very different source inputs. 13 C values are reported relative to V-PDB.