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Global synchronous increase in light-saturated and peak vegetation productivity
Kun Huang1,2, Jianyang Xia1,2
1Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, Research Center for Global Change and Complex Ecosystems, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China.
Fundamental Research
|June 11, 2026
Summary
Global vegetation productivity is increasing, with peak productivity (GPPmax) and light-saturated productivity (GPPsat) rising together. Rising atmospheric CO2 is the main driver, suggesting enhanced carbon sequestration potential.
Area of Science:
- Ecology
- Global Carbon Cycle
- Plant Physiology
Background:
- Terrestrial gross primary productivity (GPP) is the uptake of atmospheric CO2 by plants.
- GPP increases with light but saturates (GPPsat), and peak productivity (GPPmax) may be rising.
- The light-saturation constraint on enhanced GPPmax is not well understood.
Purpose of the Study:
- To investigate the light-response curves of global vegetation productivity.
- To determine if GPPmax has increased and if it is constrained by light saturation.
- To identify the drivers of changes in GPPmax and GPPsat.
Main Methods:
- Utilized 1269 site-years of FLUXNET data.
- Combined FLUXNET measurements with a flux-based gridded dataset.
- Constructed observationally derived light-response curves for global vegetation.
Main Results:
- Observed a synchronous increase in GPPmax and GPPsat globally.
- Found a consistent ratio (approx. 80%) between GPPmax and GPPsat across biomes.
- Identified CO2 fertilization as the primary driver, followed by temperature.
Conclusions:
- Rising GPPmax and GPPsat are increasing the capacity for atmospheric CO2 sequestration.
- Evergreen broadleaved forests show less light saturation, indicating further productivity potential.
- CMIP6 models project continued GPPmax increases through 2100.
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