The decline in desert drift potential weakens aeolian dust emission

Abstract

Near-surface wind speed (NSWS) is one of the most important factors shaping local terrain and geomorphological features, and its variations have significant environmental impacts, strongly influencing global dune dynamics and dust emissions. In recent years, the reduction in wind speed may have mitigated drought stress induced by rising temperatures, further weakening dust emissions. In this study, we present changes in global dust aerosol optical thickness (DOT) alongside variations in dust events, in response to alterations in desert regions associated with climate change. We find that global near-surface dust events (excluding Europe) declined annually from 2000 to 2023. Concurrently, the DOT in desert regions, specifically in the eastern Thar Desert, the Sahara Desert, and the Badain Jaran Desert, also decreased annually. This decline is primarily attributed to the reduced intensity of sand-moving wind regime in these areas, with drift potential (DP) decreasing by 37 %, 10 %, and 8 %, respectively. Additionally, dust activity has also diminished to varying degrees in parts of North Africa, Northeast Asia, South America, and Southern Africa. Finally, we project future changes in aeolian dust conditions in desert areas over the next three decades under the SSP 2–4.5 and SSP 5–8.5 scenarios. Under future simulation scenarios, the declining trend in DP is projected to intensify over the next three decades, with significant regional disparities. Notably, under the high emission scenario, the median DP of global deserts is projected to decrease by 1.1 m³ s⁻³ compared to the median under the medium emission scenario, with the reductions primarily occurring in the southern Sahara Desert and northeastern Australian deserts. Conversely, significant increases in DP are projected under high-emission scenarios in the Arabian Desert, Taklamakan Desert, and Gobi Desert. These changes are anticipated to heighten the risk of global dust events, which may be associated with large-scale ocean-atmosphere oscillations. Such projected changes will impact dune erosion and dust emissions, influencing urban and rural planning in desert regions and posing potential risks to human health.