Fig. 4
From: Global urban expansion offsets climate-driven increases in terrestrial net primary productivity
Relative contributions of urban expansion (Contr.Urb.), climate variability (Contr.Cli.) and residual factor (Contr.Res.) to change in terrestrial NPP from 2000 to 2010. This figure mainly describes spatial pattern of the relative role of climate effect, human activity and unexplained factors on terrestrial NPP change. By conducting two independent experiments as climate-variability-driven and urban-expansion-driven simulations, global terrestrial NPP was estimated as ‘urban-expansion-based NPP’ and ‘climate-variability-based NPP’. The residual factor, which is not explained by urban expansion and climate variability, was also analyzed. Relative contributions of urban expansion, climate variability, and residual factor were determined as the proportions between the trends of climate-variability-based NPP, urban-expansion-based NPP, residual factor and the sum of their absolute values. The spatial explicit approach partitioning the relative influences of urban expansion, climate variability and residual factor provides insight into the mechanisms of terrestrial ecosystem change (see Methods). NPP denotes net primary productivity.
