2026-09-15 パシフィック・ノースウェスト国立研究所（PNNL）
River flow is the result of interactions among atmospheric and land-surface processes and is influenced by human modifications to landscapes and direct water use. This study examined and summarized measured and projected changes in river flow dynamics across Earth, finding striking contrasts across regions. (From Gudmundsson et al. 2026.)
＜関連情報＞
- https://www.pnnl.gov/publications/global-river-flows-are-shifting-volume-and-timing
- https://www.nature.com/articles/s43017-025-00745-z
世界の河川流量の過去と未来の変化 Past and future change in global river flows
Lukas Gudmundsson,Manuela I. Brunner,Petra Döll,Etienne Fluet-Chouinard,Natalia Frolova,Simon N. Gosling,Yukiko Hirabayashi,Maria B. Kireeva,Xiaomang Liu,Hannes Müller Schmied,Dmitriy Magritskiy,Louise J. Slater,Lina Stein,Yves Tramblay,Kaiwen Wang,Conrad Wasko,Dai Yamazaki & Xudong Zhou
Nature Reviews Earth & Environment Published:16 December 2025
DOI:https://doi.org/10.1038/s43017-025-00745-z
Abstract
Rivers are a vital component of the global water cycle. However, human influence on climate and terrestrial systems is increasingly shaping river flow regimes. In this Review, we summarize the current understanding of past and projected changes in global river flow, focusing on annual volumes, seasonal dynamics and sudden changes. River flow observations reveal distinct regional trends, including increased flows in high-latitude regions and decreased flows in parts of the mid-latitudes and subtropics. Snow-dominated regions in particular show shifts in their seasonal cycle towards earlier flows. These patterns align broadly with historical climate model simulations, suggesting an anthropogenic climate change signal. However, attribution is complicated by the interplay of greenhouse gas emissions, CO2-driven vegetation response, land-use change and water management. Future projections indicate continued change, with certain regions experiencing wetter conditions and others intensified drying. Seasonal changes, particularly those due to altered snow dynamics, are also expected to intensify. Despite modelling and observational advances, uncertainties remain regarding the combined effects of anthropogenic climate change and direct human interventions in terrestrial systems. Closing these gaps requires improved monitoring, advances in modelling and robust attribution frameworks, in support of efficiently managing water resources, sustaining ecosystems and adapting to a changing climate.
