<p>Climate change is unequivocally altering river hydraulics worldwide, with profound implications for flow regimes, sediment dynamics, and ecological integrity. This review synthesizes global case studies from diverse regions, including the Himalayas, African river basins, and Arctic systems, to evaluate the impacts of rising temperatures, shifting precipitation patterns, and intensifying extreme weather events. Key findings highlight accelerated snow-to-rain transitions in boreal and alpine zones, permafrost thaw-induced bank instability, and increased flood and drought frequencies, which collectively disrupt seasonal flow patterns and amplify sediment transport in cryosphere-fed basins. Such changes threaten aquatic ecosystems by elevating water temperatures, degrading habitats, and endangering cold-water species, while exacerbating water scarcity and infrastructure risks. The review underscores advancements in predictive modeling, including machine learning and hybrid frameworks, to address non-stationary hydrological behaviors, though challenges persist in data-scarce regions. Effective adaptation requires multidisciplinary strategies, integrating sustainable river basin management, nature-based solutions (e.g., riparian restoration, floodplain reconnection), and engineered interventions. Emphasizing the synergy between local knowledge and scientific innovation, the study calls for dynamic socio-ecological frameworks, long-term sediment-biodiversity studies, and scalable climate-hydrological models. Proactive, integrated approaches are vital to mitigate cascading risks, safeguard ecosystem services, and balance human needs with environmental preservation in a rapidly changing climate.</p>