Zhang et al. (2026) Warming since the Last Glacial Maximum amplifies Northern Hemisphere drought expansion driven by the Pacific Decadal Oscillation

Identification

• Journal: Communications Earth & Environment
• Year: 2026
• Date: 2026-10-21
• Authors: Chao Zhang, Anmin Duan, Mingqiang Liang, Shutao Cao, Yuxin Xie, Aiguo Dai
• DOI: 10.1038/s43247-026-04186-4

Research Groups

• Center for Marine Meteorology and Climate Change, State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
• Marine Biogeochemistry Division, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
• Earth and Climate Research Center, Earth and Life Institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
• Department of Atmospheric and Environmental Sciences, State University of New York, Albany, NY, USA

Short Summary

This study reveals that Pacific Decadal Oscillation (PDO) regime shifts regulate spring precipitation by altering subtropical trough positions and associated wind patterns. Crucially, the research demonstrates that the 4-6 °C warming since the Last Glacial Maximum has significantly amplified the negative PDO drying effect across the Northern Hemisphere.

Objective

• To clarify whether the Pacific Decadal Oscillation (PDO) influences precipitation variability by affecting subtropical troughs, and how warming since the Last Glacial Maximum (LGM) modulates this relationship.

Study Configuration

• Spatial Scale: Northern Hemisphere, East Asia, North America, India-Burma region, western North America.
• Temporal Scale: Decadal (PDO modulation), Last Glacial Maximum (LGM), present-day, spring season.

Methodology and Data

• Models used: Climate simulations for present-day and Last Glacial Maximum (LGM) conditions.
• Data sources: Reanalysis data, present-day and Last Glacial Maximum (LGM) simulations.

Main Results

• A negative PDO phase deepens the India-Burma trough and shifts its base approximately 1330 km equatorward, inducing northeasterly anomalies that weaken moisture transport and suppress precipitation over East Asia.
• Concurrently, a negative PDO phase shallows the North American subtropical trough and shifts its base approximately 560 km poleward, promoting a ridge development that reduces precipitation in water-stressed western North America.
• The 4-6 °C warming since the LGM has amplified the negative PDO drying effect, increasing the affected area by 160% in East Asia and 57% in North America.

Contributions

• Provides a mechanistic understanding of how the Pacific Decadal Oscillation (PDO) regulates subtropical trough dynamics to shape spring precipitation patterns.
• Quantifies the significant amplification of PDO-driven drought expansion due to warming since the Last Glacial Maximum, offering a basis for drought risk assessments under future warming scenarios.

Funding

• National Natural Science Foundation of China (Grant Nos. 42675019, 42305016, 42030602, U2442205)
• GEOMAR Helmholtz Center for Ocean Research Kiel
• Outstanding Postdoctoral Scholarship of the State Key Laboratory of Marine Environmental Science (MEL) at Xiamen University
• Chinese Scholarship Council (File No. 202306310194)

Citation

@article{Zhang2026Warming,
  author = {Zhang, Chao and Duan, Anmin and Liang, Mingqiang and Cao, Shutao and Xie, Yuxin and Dai, Aiguo},
  title = {Warming since the Last Glacial Maximum amplifies Northern Hemisphere drought expansion driven by the Pacific Decadal Oscillation},
  journal = {Communications Earth & Environment},
  year = {2026},
  doi = {10.1038/s43247-026-04186-4},
  url = {https://doi.org/10.1038/s43247-026-04186-4}
}