Nature Climate Change, Published online: 24 December 2025; doi:10.1038/s41558-025-02508-6Whether erosion is accelerating or decelerating along Arctic rivers has been unclear, but each trend has distinct implications for the vast amount of carbon stored in permanently frozen soils. Now, research demonstrates that warming air temperatures are driving divergent outcomes for Arctic rivers, causing some to erode their banks more rapidly while others slow down.