Dai et al. (2026) Global Downstream River Flows and Continental Runoff: An Update to 2024

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Journal of Hydrometeorology
• Year: 2026
• Date: 2026-09-21
• Authors: Aiguo Dai, Jun Hu, Anmin Duan, Xianghui Guo, Liu Ming, Risheng Liang, Guizhi Wang, Minhan Dai
• DOI: 10.1175/jhm-d-26-0008.1

Research Groups

Not specified in the abstract.

Short Summary

This study updates and analyzes monthly streamflow data for the world's 936 largest rivers from 1950–2024 to quantify variations and long-term changes in continental discharge, finding that most rivers exhibit large interannual-decadal variations but insignificant long-term trends, with regional patterns consistent with precipitation trends influenced by climate variability and external forcing.

Objective

• To update downstream monthly streamflow for the world’s largest 936 rivers to 2024 using multiple data sources for quantifying variations and long-term changes in continental discharge from 1950–2024.

Study Configuration

• Spatial Scale: Global, covering the world's 936 largest rivers, with regional analyses including the central and Northeast U.S., northern Europe, most Russia, Argentina and Uruguay, northwestern Australia, most Africa, East and South Asia, eastern Australia, the western U.S., western and eastern Canada, and parts of Brazil.
• Temporal Scale: 1950–2024 for streamflow and runoff trends, with specific periods like 1948–2024 for trends, 1949–1993 for global discharge decrease, and analysis of interannual to decadal variations.

Methodology and Data

• Models used: Not specified in the abstract.
• Data sources: Multiple data sources for downstream monthly streamflow, basin-mean precipitation, observed precipitation trends, and tropical Pacific sea surface temperatures.

Main Results

• The dataset was updated with new data for 697 rivers and extended record length for 512 rivers.
• Many large rivers in South and East Asia, Africa, and parts of South America still have short records, and the number of stations with observations has decreased since 1978.
• Streamflow in major rivers exhibits large interannual to decadal variations, which are correlated with basin-mean precipitation.
• Most rivers show statistically insignificant long-term streamflow trends since 1948.
• Out of the 200 rivers with the largest discharges, only 71 (35.5%) show statistically significant streamflow trends during 1948–2024, with 34 positive and 37 negative trends.
• Global continental discharge slightly decreased from 1949–1993, then rebounded to levels slightly above the 1950–1990 mean in recent years.
• Streamflow-inferred runoff trends during 1950–2024 show coherent spatial patterns consistent with observed precipitation trends.
• Runoff and precipitation increases were observed over the central and Northeast U.S., northern Europe, most Russia, Argentina and Uruguay, and northwestern Australia.
• Runoff and precipitation decreases were observed over most Africa, East and South Asia, eastern Australia, the western U.S., western and eastern Canada, and parts of Brazil.
• Both internal climate variability (especially from the tropical Pacific) and externally forced changes (e.g., due to carbon dioxide increases) likely contributed to these regional trends.
• Below (above) normal land precipitation and runoff were observed during warm (cold) phases of tropical Pacific sea surface temperatures.

Contributions

• Provides an updated and extended dataset of monthly streamflow for 936 of the world's largest rivers, covering 1950–2024.
• Offers a comprehensive quantification of interannual to decadal variations and long-term changes in global continental discharge.
• Identifies and maps coherent spatial patterns of runoff trends globally, demonstrating their consistency with observed precipitation trends.
• Attributes regional runoff and precipitation trends to a combination of internal climate variability (tropical Pacific) and externally forced changes (e.g., CO2 increases).

Funding

Not specified in the abstract.

Citation

@article{Dai2026Global,
  author = {Dai, Aiguo and Hu, Jun and Duan, Anmin and Guo, Xianghui and Ming, Liu and Liang, Risheng and Wang, Guizhi and Dai, Minhan},
  title = {Global Downstream River Flows and Continental Runoff: An Update to 2024},
  journal = {Journal of Hydrometeorology},
  year = {2026},
  doi = {10.1175/jhm-d-26-0008.1},
  url = {https://doi.org/10.1175/jhm-d-26-0008.1}
}