This study compares CO₂ flux estimates obtained from atmospheric and oceanic inversions to assess their accuracy and interannual variability. The atmospheric inversion, using a time-dependent inverse (TDI) model with 87 stations, is compared with an ocean inversion that uses ocean interior observations and an ocean general circulation model (OGCM). The results show that the atmospheric inversion estimates are generally in good agreement with the ocean inversion, particularly in the Southern Hemisphere. The study also examines the impact of interannually varying (IAV) meteorology on the forward tracer transport model (TTM) simulations of atmospheric CO₂ concentrations. The TTM simulations using TDI-derived fluxes show improved fits to observed interannual variability in growth rates and seasonal cycles of atmospheric CO₂. The analysis suggests that using IAV meteorology and a larger observational network helps capture regional representation and interannual variabilities in CO₂ fluxes more realistically. The study concludes that the TDI model fluxes are valid and can be used to simulate atmospheric CO₂ concentrations effectively.This study compares CO₂ flux estimates obtained from atmospheric and oceanic inversions to assess their accuracy and interannual variability. The atmospheric inversion, using a time-dependent inverse (TDI) model with 87 stations, is compared with an ocean inversion that uses ocean interior observations and an ocean general circulation model (OGCM). The results show that the atmospheric inversion estimates are generally in good agreement with the ocean inversion, particularly in the Southern Hemisphere. The study also examines the impact of interannually varying (IAV) meteorology on the forward tracer transport model (TTM) simulations of atmospheric CO₂ concentrations. The TTM simulations using TDI-derived fluxes show improved fits to observed interannual variability in growth rates and seasonal cycles of atmospheric CO₂. The analysis suggests that using IAV meteorology and a larger observational network helps capture regional representation and interannual variabilities in CO₂ fluxes more realistically. The study concludes that the TDI model fluxes are valid and can be used to simulate atmospheric CO₂ concentrations effectively.