Qi et al. (2026) From temperature to VPD: shifting drivers of flash droughts amplify ecosystem risks in high-latitude cold climates

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-08-06
• Authors: Long Qi, Chunyu Dong, Tingting Chen, Kairong Lin, Lei Chen, Xiaohong Chen
• DOI: 10.1016/j.jhydrol.2026.136185

Research Groups

• School of Civil Engineering, Sun Yat-sen University, Zhuhai, China
• Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China

Short Summary

This study investigates the evolving drivers of flash droughts globally, revealing a fundamental shift from temperature to vapor pressure deficit (VPD) as the dominant trigger in high-latitude cold zones, amplifying ecosystem risks.

Objective

• To quantify the evolving drivers of flash droughts and identify shifts in their dynamics across different epochs and regions, particularly focusing on high-latitude cold climates.

Study Configuration

• Spatial Scale: Global, with a specific focus on high-latitude cold zones of the Northern Hemisphere.
• Temporal Scale: 1950–2023, divided into two epochs: pre-period (1950–1986) and post-period (1987–2023).

Methodology and Data

• Models used: XGBoost-SHAP (explainable AI framework)
• Data sources: ERA5-Land reanalysis dataset

Main Results

• High-latitude cold zones of the Northern Hemisphere have emerged as epicenters of accelerated flash drought risk, exhibiting heightened frequency (+18.0%), duration (+2.1%), and severity (+6.9%) in the post-period (1987–2023) compared to the pre-period (1950–1986).
• In these rapidly warming cold climates, vapor pressure deficit (VPD) has superseded temperature as the dominant trigger of flash droughts.
• Actual evapotranspiration (AET) during pre-drought and onset phases now predominantly drives drought intensification and severity.
• Contemporary flash droughts in high-latitude cold zones are catalyzed by acute atmospheric evaporative demand (atmospheric thirst) rather than gradual thermal increases.

Contributions

• Uncovers a fundamental shift in flash drought dynamics, identifying VPD as the new dominant trigger over temperature in high-latitude cold climates.
• Highlights high-latitude cold zones as emerging epicenters of accelerated flash drought risk, a region previously less emphasized for such rapid intensification.
• Provides a critical insight for updating current drought monitoring frameworks to incorporate VPD and AET sensitivities for improved anticipation and mitigation of vulnerabilities in cold climate ecosystems.

Funding

• Not specified in the provided text.

Citation

@article{Qi2026From,
  author = {Qi, Long and Dong, Chunyu and Chen, Tingting and Lin, Kairong and Chen, Lei and Chen, Xiaohong},
  title = {From temperature to VPD: shifting drivers of flash droughts amplify ecosystem risks in high-latitude cold climates},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.136185},
  url = {https://doi.org/10.1016/j.jhydrol.2026.136185}
}