A Coupled Climate-Water-Dust System in Arid China and Its Response to Global Change Since the Last Deglaciation

Abstract

Drylands are characterized by limited water resources, fragile ecosystems, and a heightened vulnerability to climate change. Various surface elements in drylands are closely related and studying their long-term coupling processes and mechanisms is beneficial for managing global warming impacts on drylands. This article reports on a new aeolian sedimentary sequence since the Last Deglaciation (LD) in Hexi Corridor. Combined with our previous eolian and lacustrine sedimentary sequences in the surrounding area, we found a unique regional climate-water-dust coupling process. This coupled pattern is a combined response to Northern Hemisphere solar radiation, ice sheets, and North Atlantic freshwater forcing since the LD. The melting of permafrost during the LD period and substantial erosion of the rivers originating in the Qilian Mountains jointly destroyed the stability of the surface conditions in the Hexi Corridor. Alluvial fans in the plain released a large amount of dust, which quickly accumulated in the upstream mountainous areas after transportation, thereby forming a dust cycle. However, the warmer Middle Holocene experienced stable surface conditions and weak dust activity owing to abundant water resources. As human activities continue to intensify, the climate-water-dust coupling process in this region is closely related to human interference with the surface environment, which is entirely different from the situation where natural processes predominate. This study provides new perspectives on the effects of global warming on dryland surface systems.