Wang et al. (2026) Evapotranspiration dominates vegetation cooling in drylands under hydrological limitations

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-01-22
• Authors: Ke Wang, Dongsheng Zhao, Ziwei Chen, Du Zheng
• DOI: 10.1016/j.jhydrol.2026.134988

Research Groups

• Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
• College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
• University Key Lab of Soil Ecosystem Health and Regulation in Fujian, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian Province 350002, China

Short Summary

This study quantifies vegetation-induced temperature changes in global drylands, revealing that increased vegetation leads to a net cooling effect primarily driven by evapotranspiration, with minimal albedo-induced warming, especially under hydrological limitations.

Objective

• To quantify the dominant biophysical feedback mechanism (evapotranspiration-driven cooling vs. albedo-induced warming) by which vegetation alters land surface temperature in global drylands, particularly under hydrological limitations.

Study Configuration

• Spatial Scale: Global drylands
• Temporal Scale: 2001 to 2021

Methodology and Data

• Models used: Intrinsic biophysical mechanism method
• Data sources: Satellite observations

Main Results

• Vegetation increase in global drylands resulted in a net cooling effect (ΔTs = −0.44 ± 0.14 K).
• This net cooling was overwhelmingly dominated by evapotranspiration (ΔTsf = −0.45 ± 0.14 K).
• Albedo-induced warming was found to be minimal (ΔTsa = 0.008 ± 0.004 K).
• The magnitude of ET cooling is highly sensitive to water availability, significantly diminishing when soil moisture (SM) fell below 0.15 m³/m³ and vapor pressure deficit (VPD) exceeded 1.8 kPa.
• Vegetation-induced cooling intensified over time in tropical, arid, and temperate zones within global drylands, with ΔTs declining at rates of −0.01 to −0.02 K/yr.

Contributions

• Clarifies that evapotranspiration-driven cooling is the dominant biophysical feedback mechanism in water-limited drylands, resolving previous uncertainties.
• Provides critical insights for land-management policies aimed at reducing heat stress and ecosystem risk in drylands.
• Suggests that conserving vegetation in semi-arid and dry sub-humid zones offers potential for sustained temperature regulation.
• Highlights that vegetation restoration in hyper-arid regions is unlikely to yield long-term biophysical cooling benefits due to inherent water limitations.

Funding

• Not specified in the provided text.

Citation

@article{Wang2026Evapotranspiration,
  author = {Wang, Ke and Zhao, Dongsheng and Chen, Ziwei and Zheng, Du},
  title = {Evapotranspiration dominates vegetation cooling in drylands under hydrological limitations},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.134988},
  url = {https://doi.org/10.1016/j.jhydrol.2026.134988}
}