Great Salt Lake's Historic Low Explained

The level of the Great Salt Lake in Utah reached a record low in 2022—a decline widely attributed to low stream flows from the lake's three major tributaries as a result of a combination of drought, climate change and water diversions. A new study led from Portland State University (PSU), however, has revealed that the picture is more complex than assumed—with warming temperatures also playing a significant role. The reduction in the lake's volume poses ecological and economic issues for Utah—but also public-health concerns, the research team cautions. "As the lake shrinks, it's exposing this dry lakebed that could possibly increase dust events into the metropolitan area, affecting the air quality for nearby residents," said PSU environmental scientist Siiri Bigalke in a statement.

At its historical low point—which occurred in November 2022—the Great Salt Lake measured just 4,188.5 feet above mean sea level, some 22 feet below its historic average. In their study, Bigalke and her colleagues developed a model to simulate the lake's changing volume as a product of both water coming into and evaporating out of the lake. This allowed the team to assess the relative contributions of streamflow and precipitation into the lake and evaporation off it to the record low of 2022. The analysis revealed that a reduction in streamflow into the Great Salt Lake, while significant, only accounted for about two-thirds of the decline in its volume. The rest, the researchers report, was mainly driven by increasing evaporation off the lake as a result of warmer temperatures—an effect likely only to increase going forward. "As the climate is warming, evaporation off the lake increases, so the contribution from warming to the evaporation is significant," said paper co-author and PSU climate science professor Paul Loikith. "Without the warming trend, 2022 wouldn't have been record low. Even though streamflow is dominant, the increase in evaporation was necessary to reach the record low." This, the researchers added, means that while an increase in streamflow can lead to rapid recovery in the short term, climate change is only going to lead to more water loss in the long term. "The lake has a lot of social and economic relevance for the region and Utah," Bigalke said. "It provides over $1.9 billion in annual economic revenue, serves as a vital feeding ground for millions of migratory birds and enhances snowfall over the Wasatch Mountain Range." Wasatch is home to 11 world-class ski resorts—with Salt Lake City set to host the Winter Olympics again in 2034. With their initial study complete, the team are now hoping to explore how increasing evaporation, precipitation changes and potentially also human-caused water diversions might be affecting streamflow into the Great Salt Lake. Do you have a tip on a science story that Newsweek should be covering? Do you have a question about lakes? Let us know via science@newsweek.com.

Reference:

Bigalke, S., Loikith, P., & Siler, N. (2025). Explaining the 2022 Record Low Great Salt Lake Volume. Geophysical Research Letters, 52(2). https://doi.org/10.1029/2024GL112154