Great Salt Lake’s dry lakebed ‘big’ producer of greenhouse gas emissions, study finds

Editor’s note : This article is published through the Great Salt Lake Collaborative , a solutions journalism initiative that partners news, education and media organizations to help inform people about the plight of the Great Salt Lake .

While researchers continue to investigate the effects that dust from the Great Salt Lake might have on communities, a new study highlights another concern tied to low lake levels: greenhouse gases.

The Great Salt Lake's drying lakebed produced an equivalent of 4.1 million tons of carbon dioxide and other greenhouse gases in 2020, according to a study led by the Toronto-based Royal Ontario Museum published Thursday in the journal One Earth . The lakebed likely caused a 7% jump in greenhouse gases emitted in the state.

"Human-caused desiccation of Great Salt Lake is exposing huge areas of lakebed and releasing massive quantities of greenhouse gases into the atmosphere," said lead researcher Soren Brothers 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."

The study is based on collections that researchers from the Royal Ontario Museum, Utah State University and Leibniz Institute for Freshwater Research in Germany gathered between April and November 2020. The lake's southern arm fell to a low of 4,192.1 feet elevation at the end of the year while its northern arm fell to about 4,191.7 feet elevation, per U.S. Geological Survey data. The two peaked at 4,194.9 feet elevation and 4,194.3 feet elevation, about the time the study began.

The lake's decline has long been linked to the diversion of water from its tributaries for agriculture, municipal and industrial uses, as well as some from evaporative loss especially during the region's two-decade-long megadrought.

Researchers used a greenhouse gas analyzing device attached to a closed chamber to collect data from multiple dried lakebed sites every two weeks. The portable device helped the team log carbon dioxide and methane levels in every section.

Once complete, they merged the two gases into one number to measure the impact.

The final calculation of 4.1 million tons is based on "carbon dioxide equivalents," since methane is considered a more potent greenhouse gas than carbon dioxide. The team multiplied the methane figure by 28 times to match the Environmental Protection Agency's determination of how much more potent it is than carbon dioxide.

"As far as we can tell, the Great Salt Lake itself is not a big source of (greenhouse gas) emissions, if any. But the dried-up lakebed definitely is," Brothers told KSL NewsRadio on Friday.

The study doesn't take into account anything beyond 2020. The Great Salt Lake would go onto even lower numbers after the research-gathering period, reaching a record low of about 4,188.5 feet elevation in November 2022. By then, state land managers and other experts determined that some 800 square miles of lakebed had become exposed .

The lake has recovered somewhat since then, as its southern arm reached 4,195.2 feet elevation this year — its highest point since 2019. It's now listed at 4,193.7 feet elevation, while its northern arm has risen back to 4,192.1 feet elevation after it was essentially shut off from the southern arm last year .

The Utah Office of the Great Salt Lake Commissioner is aware of the study but it was still reviewing it as of Monday, according to Tim Davis, Great Salt Lake deputy commissioner. However, he's not surprised by the findings.

Davis said he would suspect that carbon and other emissions would increase as microorganisms and vegetation typically underneath water become exposed and die off. The finding comes shortly after the office released its initial dust mitigation plan that aims to study more impacts of dust coming off the dried lakebed and ways to control it, which is another major concern tied to the dry lakebed.

Experts have said multiple times the easiest and cheapest solution to dust has been getting more water to the lake, which may very well be the case when it comes to emissions.

"It's just another reason for us to get more water to the lake so it can reach its healthy target level (of 4,198 feet)," Davis told KSL.com. "That reason also includes making sure we have a healthy ecosystem, that the communities around the lake are healthy, that the brine shrimp and the economy that depends on the lake — that all of those are healthy. (The new study) is just an additional argument for what we're trying to do."

Contributing: Adam Small