Li et al. (2026) Weakening vegetation control on global terrestrial evapotranspiration in a warmer world

Identification

• Journal: Communications Earth & Environment
• Year: 2026
• Date: 2026-03-10
• Authors: Hongbin Li, Weiguang Wang, Zefeng Chen, Xiaolei Li, Matteo Mura, Adriaan J. Teuling, Alessandro Cescatti, Giovanni Forzieri
• DOI: 10.1038/s43247-026-03372-8

Research Groups

• State Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing, China
• College of Hydrology and Water Resources, Hohai University, Nanjing, China
• Department of Civil and Environmental Engineering, University of Florence, Florence, Italy
• Yangtze Institute for Conservation and Development, Hohai University, Nanjing, China
• Jiangsu Taihu Planning and Design Institute of Water Resources Co., Ltd. Shanghai Department, Shanghai, China
• Hydrology and Quantitative Water Management Group, Wageningen University, Wageningen, The Netherlands
• European Commission, Joint Research Centre, Ispra, Italy

Short Summary

This study quantifies future changes in the sensitivity of terrestrial evapotranspiration (ET) to leaf area index (LAI) under projected warming scenarios, finding that vegetation control on ET will weaken globally by 2100 due to reduced stomatal conductance outweighing CO₂ fertilization. This weakening will diminish LAI-driven evaporative cooling, leading to enhanced water conservation.

Objective

• Quantify changes in the sensitivity of terrestrial evapotranspiration (ET) to growing-season averaged leaf area index (∂ET/∂LAI) through 2100 across different emission scenarios.
• Investigate the underlying ecological mechanisms driving these projected changes.

Study Configuration

• Spatial Scale: Global land (approximately 80% of global land area).
• Temporal Scale: Projections through 2100, with analysis of decadal changes.

Methodology and Data

• Models used: CMIP6 Earth system model simulations.
• Data sources: Satellite retrievals (e.g., for LAI, ET), observational products, reanalysis data (e.g., ERA5-Land, CRU TS), MODIS and AVHRR LAI products, GLEAM v3 (satellite-based land evaporation).
• Framework: Machine-learning framework integrating the diverse data sources.

Main Results

• The current positive sensitivity of ET to LAI (∂ET/∂LAI) is estimated at 71.53 ± 12.01 mm m² m⁻².
• This positive ∂ET/∂LAI is projected to weaken over approximately 80% of global land by 2100.
• The weakening is driven by a declining vegetation control on transpiration, particularly in warm regions and under higher-emission scenarios.
• Projected decadal weakening rates are -0.121 ± 0.026 mm m² m⁻² decade⁻¹ under SSP1-2.6 and -1.247 ± 0.075 mm m² m⁻² decade⁻¹ under SSP5-8.5.
• Conductance-based diagnostics indicate that the suppressing effect of reduced stomatal conductance increasingly outweighs the positive CO₂ fertilization effect with elevated CO₂ concentration.
• Consequently, LAI-driven evaporative cooling is expected to diminish under future conditions, leading to enhanced water conservation.

Contributions

• Provides the first quantification of future changes in the sensitivity of global terrestrial evapotranspiration to leaf area index under various climate change scenarios.
• Identifies the shift in the balance between stomatal conductance reduction and CO₂ fertilization as the primary ecological mechanism driving the weakening vegetation control on transpiration.
• Highlights the diminishing role of LAI-driven evaporative cooling and its implications for future water availability and conservation strategies.
• Integrates a novel machine-learning framework with satellite observations and CMIP6 model simulations for robust future projections.

Funding

• National Natural Science Foundation of China (U25A20752, 52479010, 52325902)
• Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX23_0708)
• China Scholarship Council (CSC) Grant (202306710120)
• Horizon Europe’s Marie Skłodowska-Curie Actions (grant no. 101152010, TYPIC)
• Horizon Europe Project ECO2ADAPT (grant agreement no. 101059498)
• ClimTip project (European Union’s Horizon Europe research and innovation programme under grant agreement no. 101137601)

Citation

@article{Li2026Weakening,
  author = {Li, Hongbin and Wang, Weiguang and Chen, Zefeng and Li, Xiaolei and Mura, Matteo and Teuling, Adriaan J. and Cescatti, Alessandro and Forzieri, Giovanni},
  title = {Weakening vegetation control on global terrestrial evapotranspiration in a warmer world},
  journal = {Communications Earth & Environment},
  year = {2026},
  doi = {10.1038/s43247-026-03372-8},
  url = {https://doi.org/10.1038/s43247-026-03372-8}
}