The Great Salt Lake is getting less great by the year

Utah's Great Salt Lake is drying out and releasing greenhouse gases into the atmosphere. The effect of drying lakes has largely not been included in climate calculations, making true emissions levels inaccurate. Salt lakes all over the world are facing similar fates, and the changes are making conservation efforts a priority. 

A very salty buffet

A study published in the journal One Earth found that 4.1 million tons of carbon dioxide and other greenhouse gases were released by the Great Salt Lake in 2020, causing a 7% increase in Utah's greenhouse gas emissions and worsening climate change. The lake has been steadily drying, falling to a record low level two years ago. While the water level has rebounded slightly in the past few years, the lake's level remains below what is considered a healthy range. 

"Human-caused desiccation of Great Salt Lake is exposing huge areas of lake bed and releasing massive quantities of greenhouse gases into the atmosphere," Soren Brothers, lead author of the study, said in a statement. "The significance of lake desiccation as a driver of climate change needs to be addressed in greater detail and considered in climate change mitigation and watershed planning." 

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The emissions come from microorganisms releasing carbon dioxide while feeding on materials exposed to the drying lakebed. "Everything that's flowed into that lake over the last 10,000 years or so since it's existed has ended up on that big lake bottom," Brothers said to The Salt Lake Tribune. "It's a huge buffet for bacteria to consume. Suddenly they have access to 10,000 years of deposited organic matter that's been off-limits until then." As the lake dries, more matter is exposed for consumption. Human actions, namely agriculture, are mostly to blame for the drying of the Great Salt Lake. "Upstream water diversions for expanding alfalfa farms and dairies have resulted in less flows into the lake," said NPR. "Utah's rapid population growth has also been to blame."

Lost in calculation

The true magnitude of emissions caused by drying lakes is understated in climate calculations. "They must include the drying lakes in those inventories," Rafael Marcé, a research scientist at the Centre for Advanced Studies in Blanes, Spain, said to The Washington Post. "Because in the case of very big lakes, they could be missing something which is very relevant." 

In addition, the loss of water can have major impacts on the surrounding ecosystem. Shorebird and brine shrimp populations have been declining in the region. Dust storms have also increased, worsening air pollution. "Scientists have warned that the lake has high concentrations of neurotoxins and cancer-causing carcinogens — including arsenic and mercury," said NPR.

The good news is that attention has been paid. "For generations, the lake was seen as kind of this dead thing that just happens to be there and will always be there," Utah Gov. Spencer Cox said to NPR. "Now that people are realizing there's a potential that it might not always be here, that's gotten people's attention in a positive way." The Utah state legislature has invested approximately $1 billion in water conservation efforts.

Salt lakes account for approximately 44% of the volume and 23% of the surface area of lakes worldwide. "The significance of lake desiccation as a driver of climate change needs to be addressed in greater detail and considered in climate change mitigation and watershed planning," said Brothers.