Fig. 1: Long-term changes in global annual photosynthesis from TBMs and multiple satellite observations.

a, Relative changes in global terrestrial photosynthesis (∆GPP, %) from 1982 (CO₂ = 341 ppm) to 2012 (CO₂ = 391 ppm) based on simulations from process-based models in the TRENDY project model ensemble (orange, mean ± s.d.) and two different satellite approaches (empirical MODIS algorithm (MA, solid lines); a machine learning method (ML, dashed lines)). Estimates from the satellite approaches were obtained allowing for an effect of increasing CO₂ on either the fAPAR (red lines, dots), the LUE of photosynthesis (blue line) or both fAPAR and LUE (black lines, dots). b, Inferred CO₂ sensitivities (\({\beta }_{{\rm{R}}}^{{\rm{GPP}}}\); Methods) from the data presented in a, for the standard satellite-based approaches using ML and the MODIS algorithm (MA) with the CO₂ effect on GPP manifest through changes in fAPAR, the modified MA approach with a CO₂ effect only on LUE (MA, only LUE) and both ML and MA satellite RS-based approaches with an effect of increasing CO₂ on both LUE and fAPAR. Black error bars represent the mean standard error of \({\beta }_{{\rm{R}}}^{{\rm{GPP}}}\) for each product (MA, ML) or the mean standard error across TRENDY models.