River-controlled permafrost dynamics are crucial for sediment transport, infrastructure stability, and carbon cycle, yet are not well understood under climate change. Leveraging remotely sensed datasets, in-situ hydrological observations, and physics-based models, we reveal overall warming and widening rivers across the Tibetan Plateau in recent decades, driving accelerated sub-river permafrost thaw. River temperature of a representative (Tuotuohe River) on the central Tibetan Plateau, has increased notably (0.39 degrees C/decade) from 1985 to 2017, facilitating heat transfer into the underlying permafrost via both convection and conduction. Consequently, the permafrost beneath rivers warms faster (0.37 degrees C-0.66 degrees C/decade) and has a similar to 0.5 m thicker active layer than non-inundated permafrost (0.17 degrees C-0.49 degrees C/decade). With increasing river discharge, the inundated area expands laterally along the riverbed (16.4 m/decade), further accelerating permafrost thaw for previously non-inundated bars. Under future warmer and wetter climate, the anticipated intensification of sub-river permafrost degradation will pose risks to riverine infrastructure and amplify permafrost carbon release.

Erosion of riverbanks is a natural phenomenon, which leads to the loss of important agricultural land areas. At the same time, riverbank erosion can be considered a natural risk that can cause major damage to road and railway infrastructure, flood management infrastructure, biodiversity and even the population located in flood risk areas. This phenomenon is generally more pronounced in the meanders of the rivers and in regions with higher flow rates, but it can be accentuated due to climate change which can lead to changes in watercourse flows. This study aimed to estimate the net annual soil loss due to riverbank erosion on the Siret River, Romania, using aerial photogrammetry and GIS analysis.