J. A. O’Donnell Joshua C. Koch 2025 <h3 class="c-article__sub-heading" data-test="abstract-sub-heading">Purpose of Review</h3><p>Streams and rivers are undergoing rapid change as the Arctic warms and thaws. We review recent observations in Arctic stream systems to identify ubiquitous changes and the most useful tools for observing change and exploring the underlying processes.</p><h3 class="c-article__sub-heading" data-test="abstract-sub-heading">Recent Findings</h3><p>Recent literature indicates increasingly significant trends in river hydrology and chemistry due to persistent warming in the Arctic and longer observational records for analysis. However, regional differences in the magnitude and direction of these trends persist. We also observe thresholds in ground thaw and surface–groundwater interactions that can impact river hydrology and chemistry.</p><h3 class="c-article__sub-heading" data-test="abstract-sub-heading">Summary</h3><p>Warming and thaw are occurring rapidly at high latitudes, resulting in increasing, yet variable responses in stream systems across regions and scales. These differences highlight the need for long-term records and an interdisciplinary approach to explain trends and predict future states. Stream systems respond to multiple landscape changes related to hydrology (changing precipitation and subsurface flow), geology (ground thaw dynamics), and ecology (vegetation change).</p> application/pdf 10.1007/s40641-025-00202-5 en Springer Nature Observing northern high-latitude river systems to understand changes in a warming Arctic article