Data to support 'The size of tropical vegetation gross primary production'

Satellite-based optical observations have converged to show average estimates of global contemporary gross primary production (GPP), the photosynthetic assimilation of atmospheric CO2 by terrestrial vegetation, at 120-140 Pg C yr–1. This consensus was challenged by a recent modeling study conducted by Lai et al in Nature, which posits a higher global estimate of 157±8.5 Pg C yr-1, revealing a pronounced discrepancy in the tropics where modeled fluxes of 79 Pg C yr-1 exceed satellite-derived values by a factor of 1.33-1.85. We demonstrate that L24’s extrapolation is methodologically flawed, as it generalizes a site-specific temporal relationship between the ratio of carbonyl sulfide (OCS) to CO2 fluxes (LRU) and photosynthetically active radiation (PAR) from a single boreal station and also neglects the critical influence of vapor pressure deficit (VPD). This finding underscores the need for caution in upscaling site-level physiological constraints to the global scale, warranting the necessity of a global comprehensive validation before conducting for global estimates.