A desiccating saline lake bed is a significant source of anthropogenic greenhouse gas emissions

Abstract

Saline lake desiccation is widespread and typically caused by anthropogenic withdrawals for agricultural, industrial, and municipal uses, but its impact on greenhouse gas (GHG) emissions is unknown. While dry-flux studies have shown that desiccating waterbodies emit carbon dioxide (CO₂) and methane (CH₄) from exposed sediments, these studies are often seasonal and for freshwater systems, limiting their application to chronically desiccating saline lakes. We measured CO₂ and CH₄ emissions (April to November, 2020) from the exposed sediments of Great Salt Lake (Utah, United States), and compared them with aquatic emissions estimates to determine the anthropogenic emissions associated with desiccation. In 2020, the lake bed emitted 4.1 million tons of CO_2eq to the atmosphere, primarily (94%) as CO₂, constituting a ∼7% increase to Utah’s anthropogenic GHG emissions. As climate change exacerbates drought in arid regions, anthropogenic desiccation and associated climate feedbacks should be considered in assessments of global GHG trajectories as well as local GHG emissions reduction efforts.