Recent research has revealed that the drying lake bed of the Great Salt Lake in Utah released an astounding 4.1 million tons of carbon dioxide and other greenhouse gases in the year 2020. This study highlights the often-overlooked role of desiccated lake beds in contributing to greenhouse gas emissions, which may become more significant as climate change progresses.
Recent findings from the Royal Ontario Museum (ROM) reveal that the drying lake bed of the Great Salt Lake, Utah, emitted 4.1 million tons of carbon dioxide and various greenhouse gases during 2020. This study points to desiccated lake beds as an underappreciated but possibly substantial source of greenhouse gases, a situation likely to worsen with ongoing climate change. The results of this research were shared in the article titled, “A desiccating saline lake bed is a significant source of anthropogenic greenhouse gas emissions,” published in the journal One Earth.
“Human-induced drying of the Great Salt Lake is revealing extensive areas of lake bed and releasing enormous amounts of greenhouse gases into the atmosphere,” stated Soren Brothers, the lead researcher and ROM’s Allan and Helaine Shiff Curator of Climate Change. “The impact of lake drying on climate change warrants further exploration and should be included in climate change mitigation strategies and watershed management.
The water level of the Great Salt Lake fluctuates from year to year, primarily based on the meltwater inflow from nearby mountains—ranging from peak levels in the 1980s to record lows in 2022. However, human activities such as agricultural, industrial, and municipal water consumption have led to the continuous depletion of the lake. Similar competing demands for water are affecting lake levels around the globe. As famous saline lakes like the Aral Sea, Lake Urmia, and the Caspian Sea dry up, they not only obliterate essential habitats for various species and worsen air quality, impacting human health, but also contribute to climate change as newly exposed soils release carbon dioxide and methane.
The research team assessed the emissions of carbon dioxide and methane from the exposed Great Salt Lake sediments between April and November 2020, comparing these with estimates of aquatic emissions to quantify the human-induced greenhouse gas emissions resulting from lake desiccation. Their calculations suggested that the lake bed released 4.1 million tons of greenhouse gases, with carbon dioxide making up 94% of that total, amounting to about a 7% increase in Utah’s greenhouse gas emissions from human activities.
This field research was conducted while Soren Brothers served as an Assistant Professor of Limnology at Utah State University, and lead author Melissa Cobo was pursuing her master’s degree at USU. Co-author Tobias Goldhammer collaborated from the Leibniz Institute for Freshwater Research (IGB Institute) in Berlin, Germany. They measured carbon dioxide and methane levels every two weeks using a portable greenhouse gas analyzer linked to a closed chamber on the dried lake bed. Multiple sampling sites were visited throughout the year, with additional locations assessed during an in-depth three-day campaign to analyze spatial variability across the lake, which is the largest saline lake in the western hemisphere, covering 1,700 square miles (4,400 square kilometers).
Since methane is 28 times more effective as a greenhouse gas compared to carbon dioxide, the overall climatic impact of these emissions was calculated in “carbon dioxide equivalents” to recognize methane’s heightened effect. Ultimately, the data showed that greenhouse gas emissions from the exposed lake bed had a strong positive correlation with higher temperatures, even in areas that have been dry for over twenty years. To understand whether the lake would historically have been a substantial source of greenhouse gases, the researchers conducted near-shore emission measurements and analyzed water chemistry data from both their team and government sources. These results indicated that the original lake was unlikely to have been a significant atmospheric greenhouse gas source, hence marking the dried lake bed as a new contributor to atmospheric warming.
With climate change intensifying drought conditions in arid regions, the drying of rivers and lakes may be enhancing feedback loops that impact climate change. This factor should be taken into account in evaluations of global greenhouse gas emissions and in reduction strategies.
