The Contribution of Ephemeral Lakes to Global Dust Cycle and Direct Radiative Effect

Abstract

Despite their tiny size, ephemeral lakes with their dry smooth surface may play a major role in the dust life cycle at global scale. However, their impacts on Earth's climate systems, and in particular direct radiative effects have been unexplored. Our results show that ephemeral lakes contribute as much as 52% of dust emission in the Southern Hemisphere (SH), but only 10% in the Northern Hemisphere and 13% globally. Due to the action of physical processes, dust mineralogy of the lakes differs from their surroundings. With no reliable data sets, we performed a sensitivity analysis of dust absorption. With increasing absorption from lakes, lake dust's radiative cooling decreases from −0.1 to −0.03 Wm⁻², globally. These findings highlight the dominant role of ephemeral lakes in the SH dust budget and underscore the need to include them in climate models to better represent dust-radiation interactions and ocean biogeochemical feedback.