Recent Desertification in the Yellow River Source Region Driven by Winter Warming

The Yellow River source region (YRSR) is a critical water source for northern China， and is undergoing desertification with its major drivers remaining unclear. Here， we reconstruct the history of aeolian activity over the past ～2000 years using grain-size analysis of sediments from Lake Ngoring. A sensitive aeolian fraction was identified from surface samples and extracted from a sediment core. The record shows weak aeolian activity before ～1000 AD， episodic intensification from ～1000 to ～1650 AD， and a sharp increase thereafter， marking the onset of rapid desertification that is independently corroborated by pollen records. We find that， while reduced precipitation provided a long-term drying background， winter warming likely played an important role in enhancing aeolian activity during the late period. Winter warming may have increased sediment availability and surface erodibility through permafrost degradation， soil desiccation， and vegetation loss. These processes may have formed a positive feedback mechanism that further reinforced aeolian activity. Our findings highlight the important role of winter warming under a persistent arid background in modulating aeolian activity and accelerating desertification in this vulnerable alpine region， offering critical insights for ecological risk assessment.