Tang et al. (2025) Emergent constraints reveal underprediction of future global water availability under anthropogenic forcing

Identification

• Journal: Global and Planetary Change
• Year: 2025
• Date: 2025-12-16
• Authors: Senlin Tang, Qiang Zhang, Xintong Gong, Chong-Yu Xu, Vijay P. Singh, Fubao Sun, Yao Feng, Ziwei Li, Likun Han
• DOI: 10.1016/j.gloplacha.2025.105252

Research Groups

• Advanced Interdisciplinary Institute of Environment and Ecology, Guangdong Provincial Key Laboratory of Wastewater Information Analysis and Early Warning, Beijing Normal University, Zhuhai, China
• Department of Geosciences and Hydrology, University of Oslo, Oslo, Norway
• Department of Biological and Agricultural Engineering, Texas A&M University, College Station, TX, USA
• Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX, USA
• National Water and Energy Center, UAE University, Al Ain, United Arab Emirates
• Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Science and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
• University of Chinese Academy of Sciences, Beijing, China
• Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Science, Fudan University, Shanghai, China
• Key Laboratory of Polar Atmosphere-ocean-ice System for Weather and Climate of Ministry of Education, Fudan University, Shanghai, China

Short Summary

This study identifies the drivers of global water resource changes, attributing the observed upward trend primarily to greenhouse gas forcing, and employs an emergent constraint method to reduce uncertainties in future projections, revealing a significant underestimation of future global water availability.

Objective

• To identify the drivers and quantify the uncertainties, including their spatial heterogeneity, influencing global water availability.
• To reduce uncertainties in future projections of global water resources under anthropogenic forcing using an emergent constraint method.

Study Configuration

• Spatial Scale: Global
• Temporal Scale: Historical analysis (1980–2014), emergent constraint application (1995–2014), future projections (2081–2100).

Methodology and Data

• Models used: Optimal fingerprinting, emergent constraint method.
• Data sources: Historical observations, climate model simulations under SSP2–4.5 and SSP5–8.5 scenarios.

Main Results

• Greenhouse gas (GHG) forcing explains approximately 77.6 % of the observed upward trend in global water resources from 1980 to 2014, significantly outweighing natural external forcing (45.8 %) and aerosols (−23.4 %).
• Model uncertainty accounts for approximately 89.2 % of the total variance in future global water-resource projections.
• Constrained projections revealed an underestimation of future water-resource changes by 18.0 % under SSP2–4.5 and 13.4 % under SSP5–8.5 for the 2081–2100 period.
• Model uncertainty in future projections was reduced by 33.1 % (SSP2–4.5) and 26.4 % (SSP5–8.5) after applying the emergent constraint.

Contributions

• Advances the understanding of the drivers and uncertainties in global water resources.
• Provides more reliable future projections of global water availability by substantially reducing model uncertainty through the integration of historical observations with the emergent constraint method.
• Offers critical information for informing adaptation strategies and long-term water resources planning.

Funding

Not specified in the provided text.

Citation

@article{Tang2025Emergent,
  author = {Tang, Senlin and Zhang, Qiang and Gong, Xintong and Xu, Chong-Yu and Singh, Vijay P. and Sun, Fubao and Feng, Yao and Li, Ziwei and Han, Likun},
  title = {Emergent constraints reveal underprediction of future global water availability under anthropogenic forcing},
  journal = {Global and Planetary Change},
  year = {2025},
  doi = {10.1016/j.gloplacha.2025.105252},
  url = {https://doi.org/10.1016/j.gloplacha.2025.105252}
}