Qu et al. (2026) Drought propagation as a nonlinear amplifier of ecohydrological damage

Identification

• Journal: Communications Earth & Environment
• Year: 2026
• Date: 2026-02-27
• Authors: Z. Qu, Xiaoyan Li, Josep Peñuelas, Deliang Chen, Chiyuan MIAO, Yuanhong Deng, Fangzhong Shi, Wenqi Li
• DOI: 10.1038/s43247-026-03330-4

Research Groups

• State Key Laboratory of Earth Surface Processes and Hazards Risk Governance (ESPHR), Faculty of Geographical Science, Beijing Normal University, Beijing, China
• School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing, China
• CREAF, Cerdanyola del Vallès, Barcelona, Spain
• CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Barcelona, Spain
• Department of Earth System Sciences, Tsinghua University, Beijing, China
• College of Urban and Environmental Sciences, Peking University, Beijing, China

Short Summary

This study systematically investigates how meteorological drought propagates to soil and ecological drought, revealing that ecohydrological damage is nonlinearly amplified, reaching 162% to 310% of initial meteorological drought intensity, especially beyond a standardized threshold of 2.18.

Objective

• To systematically assess if ecohydrological damage (sum of standardized vegetation greenness and soil moisture losses) is disproportionately amplified through drought propagation.
• To quantify the propagation time, intensity, and resulting ecohydrological damage along different drought propagation pathways.
• To examine how meteorological droughts of distinct origins—precipitation deficit versus potential evapotranspiration surplus—affect drought propagation.
• To evaluate how soil–vegetation feedback modulates drought propagation and its ecohydrological damage.

Study Configuration

• Spatial Scale: Global, with data aggregated to a 0.5° spatial resolution.
• Temporal Scale: Monthly time steps over the period 1982–2020.

Methodology and Data

• Models used: GLEAM (for root-zone soil moisture), BESSv2.0 (for GPP, NEE), Back Propagation Neural Network (for GIMMS LAI4g product), Machine Learning (for RTSIF product), Stegmented regression model (for breakpoint detection), Convergent Cross Mapping (for causal relationships), Linear regressions (for mediation analysis).
• Data sources: Satellite observations (GIMMS LAI4g, RTSIF), reanalysis data (GLEAM, ERA5-Land), gridded climate data (CRU TS), and model outputs (BESSv2.0).

Main Results

• Ecohydrological damage, defined as the sum of standardized vegetation greenness and soil moisture losses, was amplified by drought propagation, reaching 162% to 310% of the initial meteorological drought intensity.
• A nonlinear amplification was observed: ecohydrological damage sharply escalated once meteorological drought intensity exceeded a standardized threshold of 2.18, while propagation time rapidly decreased with increasing intensity, with an abrupt jump at a threshold of 3.08.
• Globally, 99% of affected areas experienced amplified ecohydrological damage, with 77% showing at least a two-fold and 30% a more than three-fold exacerbation, particularly in mid- to high latitudes of North America, northern South America, and humid/dry sub-humid Eurasia.
• Soil and ecological droughts exhibited significantly lower resilience and slower recovery compared to meteorological drought, contributing to amplified damage.
• Precipitation deficits primarily drove soil droughts (0-month lag), while potential evapotranspiration surpluses primarily drove ecological droughts (0–2 month lag).
• The meteorological–soil–ecological drought (M–S–E) pathway resulted in the most severe ecohydrological damage (3.10 times initial meteorological drought intensity), whereas the meteorological–ecological–soil drought (M–E–S) pathway resulted in 2.65 times the initial intensity.
• Internal soil–vegetation feedbacks facilitated drought propagation in the M–S–E pathway (lower antecedent soil moisture intensified ecological drought) but dampened it in the M–E–S pathway (lower antecedent leaf area index buffered soil drought development).

Contributions

• Provides a systematic, quantitative assessment of the full propagation pathways, timing, and ecohydrological damage of meteorological droughts progressing into soil and ecological droughts.
• Distinguishes the differing effects of droughts caused by precipitation deficits versus those driven by excess potential evapotranspiration.
• Elucidates the bidirectional feedbacks between soil and ecological drought and their modulation of drought propagation.
• Offers critical insights for advancing early warning systems and mitigating cascading drought losses, particularly in the context of declining ecosystem resilience and increasing climate variability.

Funding

• National Natural Science Foundation of China (42521001)
• China Scholarship Council (CSC)
• Talents Incubation Project of School of Natural Resources at Beijing Normal University (2024YC06)
• Tsinghua University (100008001)

Citation

@article{Qu2026Drought,
  author = {Qu, Z. and Li, Xiaoyan and Peñuelas, Josep and Chen, Deliang and MIAO, Chiyuan and Deng, Yuanhong and Shi, Fangzhong and Li, Wenqi},
  title = {Drought propagation as a nonlinear amplifier of ecohydrological damage},
  journal = {Communications Earth & Environment},
  year = {2026},
  doi = {10.1038/s43247-026-03330-4},
  url = {https://doi.org/10.1038/s43247-026-03330-4}
}