Airborne and everywhere: evolving role of the modern dust cycle in the earth system

Dust has played a critical role throughout Earth’s origin and evolution and continues to do so in the present. The expanding scale and increasing pace of anthropogenic activities over the last few centuries have resulted in a dustier 21st-century world that influences all aspects of planetary life, from personal health to global biogeochemical cycling of elements and climate. In recent years, measurements and models have advanced our understanding of global dust flux. However, uncertainties remain over the quantification and role of low-level emissions and depositions, episodic and extreme dust events, high-latitude dust, bioaerosols, and anthropogenic dust. Furthermore, the ecological consequences of dust loss to source regions, its reactivity in the atmosphere, and dust gain in depositional ecosystems remain underappreciated. Even as dust influences climate and the changing climate impacts dust in a feedback loop, several aspects of the dust life cycle, such as the role of dust in the global carbon cycle and the contribution of anthropogenic dust to Earth’s radiation budget, remain poorly constrained. In a world wherein the continents are measurably losing freshwater and soil moisture (undergoing aridification), and wildland and urban fires are increasing in frequency and intensity, dust is emerging as a major player at local, regional, and global scales. Nevertheless, dust remains an underappreciated and understudied component of global biogeochemical cycles (especially its role in biospheric productivity) and climate models (especially its role in climate feedback). This commentary aims to inform, intrigue, and challenge Earth scientists to pursue research on the fast-evolving modern dust cycle—its sources, sinks, fluxes, size distribution, composition, abundance, reactivity, consequences, and fate in the Earth system.