Wang et al. (2025) Recent south-central Andes water crisis driven by Antarctic amplification is unprecedented over the last eight centuries

Identification

• Journal: Communications Earth & Environment
• Year: 2025
• Date: 2025-11-20
• Authors: Shijie Wang, Mao Hu, Feng Chen, Xiaoen Zhao, Martín A. Hadad, Fidel A. Roig, David M. Meko, Max C. A. Torbenson, Sergio Piraino, Heli Zhang, Xu Yang, Youping Chen, Weipeng Yue, Honghua Cao
• DOI: 10.1038/s43247-025-02858-1

Research Groups

• Yunnan Key Laboratory of International Rivers and Transboundary Eco-Security/Ministry of Education Key Laboratory for Transboundary Eco‑Security of Southwest China, Institute of International Rivers and Eco-Security, Yunnan University, Kunming, China
• State Key Laboratory of Vegetation Structure, Functions and Construction (VegLab), Yunnan University, Kunming, China
• Southwest United Graduate School, Kunming, China
• Key Laboratory of Tree-ring Physical and Chemical Research of the Chinese Meteorological Administration/Xinjiang Laboratory of Tree-ring Ecology, Institute of Desert Meteorology, Chinese Meteorological Administration, Urumqi, China
• Laboratorio de Dendrocronología de Zonas Áridas-Instituto y Museo de Ciencias Naturales, Universidad Nacional de San Juan, CIGEOBIO (CONICET-UNSJ), San Juan, Argentina
• Laboratorio de Dendrocronología e Historia Ambiental, IANIGLA-CCT CONICET-Universidad Nacional de Cuyo, Mendoza, Argentina
• Hémera Centro de Observación de la Tierra, Escuela de Ingeniería Forestal, Facultad de Ciencias, Universidad Mayor, Huechuraba, Santiago, Chile
• Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ, USA
• Department of Geography, Johannes Gutenberg University, Mainz, Germany
• Global Change Research Institute of the Czech Academy of Science, Brno, Czech Republic
• Facultad de Ciencias Agrarias, Universidad Nacional de Cuyo, Mendoza, Argentina
• Institute of Global Environmental Change, Xi’an Jiaotong University, Xi’an, China
• School of Ecology and Environmental Science, Yunnan University, Kunming, China

Short Summary

This study reconstructs 827 years of Negro River streamflow in northern Patagonia using tree-ring records, revealing an unprecedented decline in recent decades. This decline is primarily driven by Antarctic amplification, which exacerbates temperature rise and disrupts circulation patterns, intensifying regional aridity.

Objective

• To develop a reliable streamflow reconstruction for the mainstem of the Negro River in Patagonia and identify periods of water crises.
• To identify and quantify the primary hydroclimatic drivers of streamflow variability, assessing their relative contributions.
• To explore potential large-scale driving mechanisms, particularly the role of Antarctic amplification.
• To project future risks to the Negro River under warming scenarios.

Study Configuration

• Spatial Scale: Negro River basin, northern Patagonia, south-central Andes Mountains, Southern Hemisphere, Antarctic Peninsula.
• Temporal Scale: 827 years (1197 CE – 2023 CE) for streamflow reconstruction; 1928–2017 for observed data; 1850–2100 for future projections.

Methodology and Data

• Models used:
  • Linear regression model (for streamflow reconstruction)
  • Quantile Mapping (QM) method (for bias correction)
  • Multiple Linear Regression (MLR) method (for climate variable contributions)
  • Hierarchical Partitioning (HP) method (for individual climate variable contributions)
  • Community Earth System Model-Last Millennium Ensemble (CESM-LME)
  • Neural network technique (for CMIP6 downscaling)
  • Coupled Model Intercomparison Project Phase 6 (CMIP6) ensemble
• Data sources:
  • Tree-ring records (Araucaria araucana) from south-central Andes foothills (new samples and International Tree-Ring Data Bank - ITRDB).
  • Observed monthly streamflow data: Global Runoff Data Center (GRDC) for Primera Angostura station.
  • Observed gridded monthly hydroclimatic data: Climate Research Unit (CRU TS4.07) for precipitation, maximum, mean, and minimum temperatures, potential evaporation, and Palmer Drought Severity Index (PDSI).
  • Standardized Precipitation Evapotranspiration Index (SPEI) dataset (Consejo Superior de Investigaciones Científicas - CSIC).
  • Global monthly gridded surface runoff dataset (G-RUN) (Institute for Atmospheric and Climate Science of the Eidgenössische Technische Hochschule Zürich - IAC ETH Zurich).
  • Soil moisture data (0–10 cm depth): NASA’s FEWS NET Land Data Assimilation System (FLDAS).
  • Global monthly gridded Sea Surface Temperature (SST) dataset (HadISST1) and Sea Level Pressure (SLP) dataset (HadSLP2r) (Hadley Center, UK Met Office).
  • Global surface temperatures: Berkeley Earth Surface Temperature Project.
  • Paleo-hydroclimatic reconstructed data: Paleo Hydrodynamics Data Assimilation product (PHYDA) and South American Drought Atlas (SADA).

Main Results

• The reconstructed Negro River streamflow for 827 years (1197–2023 CE) has a mean of approximately 910 cubic meters per second (m³/s) and a standard deviation of 351.849 m³/s.
• The recent decline in Negro River streamflow is unprecedented over the past 827 years, showing the lowest combined values for decline rate and duration.
• Since the 20th century, the Negro River has experienced a sustained flow reduction of approximately 10% per decade.
• Eight climate variables (precipitation, PDSI, SPEI, soil moisture, maximum, mean, and minimum temperatures, and potential evapotranspiration) jointly contributed to 64.9% of the reconstructed streamflow variation, with PDSI (13.7%) and soil moisture (12.8%) being the largest contributors.
• Warming is increasingly contributing to severe droughts, with the effect of evapotranspiration due to higher temperatures becoming comparable to that of precipitation.
• Severe streamflow declines are associated with La Niña and positive Southern Annular Mode (SAM) years, corresponding to average streamflow deviations of –110.785 m³/s and –134.752 m³/s, respectively.
• Antarctic amplification, with a warming rate more than three times the global average, is profoundly altering atmospheric circulation, pulling westerlies southward, reducing moisture supply, and intensifying regional evapotranspiration, thereby exacerbating the water crisis.
• Future projections under SSP2-4.5 and SSP5-8.5 scenarios indicate continued streamflow declines of –3.78% to –7.57% per decade, respectively, primarily driven by Antarctic amplification.

Contributions

• Provides the first 827-year streamflow reconstruction for the mainstem of the Negro River in Patagonia, offering an unprecedented long-term perspective on hydrological variability.
• Quantifies the combined effects and individual contributions of regional climate variables to Negro River streamflow variability.
• Identifies Antarctic amplification as a critical, unprecedented driver intensifying regional aridity and streamflow decline through its modulation of ENSO and SAM.
• Projects future streamflow risks under warming scenarios, highlighting the urgent need for adaptive water management strategies in the south-central Andes region.
• Offers a historical baseline for evaluating current and future water resources, particularly emphasizing the exceptional nature of recent declines compared to past centuries.

Funding

• National Natural Science Foundation of China (NSFC project No. 32061123008)
• Excellent Research Group Program for Tibetan Plateau Earth System (No. 42588201)
• Agencia Nacional de Promoción Científica y Tecnológica of Argentina (PICT-2018-1056 to MAH)
• Cooperation International Project between CONICET and NSFC-2019

Citation

@article{Wang2025Recent,
  author = {Wang, Shijie and Hu, Mao and Chen, Feng and Zhao, Xiaoen and Hadad, Martín A. and Roig, Fidel A. and Meko, David M. and Torbenson, Max C. A. and Piraino, Sergio and Zhang, Heli and Yang, Xu and Chen, Youping and Yue, Weipeng and Cao, Honghua},
  title = {Recent south-central Andes water crisis driven by Antarctic amplification is unprecedented over the last eight centuries},
  journal = {Communications Earth & Environment},
  year = {2025},
  doi = {10.1038/s43247-025-02858-1},
  url = {https://doi.org/10.1038/s43247-025-02858-1}
}