25 September 2019

The CO2 Fertilization Effect on Global Plant Biomass

Quantifying the sensitivity of global plant biomass to CO2.


Earth System Models are widely used to examine long-term changes in ecosystem function, but validation and attribution of observed changes can be difficult. This problem is particularly relevant for the effect of rising CO2, which is expected to increase leaf area and ecosystem productivity, due to the low signal to noise ratio and limited duration of most observations. Combining ecosystem experiments with models and remote sensing observations provides a potential opportunity to overcome these limitations.


The results suggest large past and potential future increases in global biomass and LAI due to the effect of elevated CO2, emphasizing the importance of observation networks in the coming decades. Further, these results demonstrate the potential of combining models and remote sensing observations with results from ecological experiments.


We combine models, remote sensing, and observations from elevated CO2 experiments to identify a strong effect of eCO2 on global biomass accumulation, modulated by both climate and nutrient availability. The response we identify from eCO2 experiments is consistent with the global distribution of changes in leaf area and biomass observed from remote sensing, suggesting that those changes are primarily due to eCO2. The results suggest that CO2 levels expected by 2100 can potentially enhance plant biomass by ~12% above current values.

William J. Riley
Lawrence Berkeley National Laboratory
Terrer, C, R Jackson, I Prentice, T Keenan, C Kaiser, S Vicca, J Fisher, et al.  2019.  "Nitrogen and phosphorus constrain the CO2 fertilization of global plant biomass."  Nature Climate Change 9(9): 684-689.  https://doi.org/10.1038/s41558-019-0545-2.