Post-LGM global warming suppresses basin-wide erosion flux on the Tibetan Plateau by weakening frost cracking intensity

Predicting how much sediment rivers carry is vital for understanding landscape evolution. Most existing models work well for soil-covered hills, where hillslopes are fully soil mantled. However, these models often struggle in rocky, high-altitude regions where sediment supply is limited by how fast bedrock breaks down (weathering-limited). The Tibetan Plateau offers a prime example of such a cold, bedrock-dominated landscape. In this study, we investigated whether “frost cracking intensity” (Fci)–a measure of how effectively ice breaks rock—controls erosion rates. By analyzing erosion data derived from specific isotopes (10Be) in river sands, we found that in the coldest catchments (Fci>5 °C/cm), frost cracking is a important driver of sediment production. Including Fci in our predictive models significantly improved their accuracy compared to using topography alone. This suggests that freeze-thaw cycles effectively shatter bedrock, preparing it for transport. Additionally, we propose that the warming climate since the last Ice Age has likely reduced this frost action, which helps explain why modern sediment fluxes measured at gauging stations are often lower than long-term geological rates.