On this episode of Possibly, we’re taking a look at the Great Salt Lake. The lake has been shrinking for years, but it’s also doing something strange- it’s creating more greenhouse gas emissions than people expected.

Megan Hall: Welcome to Possibly, where we take on huge problems like the future of our planet and break them down into small questions with unexpected answers. I’m Megan Hall.

Today, we’re taking a trip to the Great Salt Lake in Utah, which is the 8th largest salt water lake in the world, but it’s shrinking. And the lake is also doing something strange- it’s creating more greenhouse gas emissions than people expected. Here to explain are Emma Mejia and Hamid Torabzadeh from our Possibly Team.

Emma Mejia: Hello!

Hamid Torabzadeh: How’s it going?

Megan Hall: So how does a lake create greenhouse gas emissions?

Emma Mejia: To help us answer this question, we talked to one of the scientists who worked on this investigation.

Soren Brothers: My name is Soren Brothers. The Allan and Helaine Shiff Curator of Climate Change at the Royal Ontario Museum, and for research I’m a limnologist, so I study lakes.

Hamid Torabzadeh: Soren says it’s important to understand something about the Great Salt Lake-

Soren Brothers: There’s nothing that flows out of it. All of the stuff that flows into that lake has settled on the lake bottom.

Emma Mejia: The Great Salt lake is around 11,000 years old, so there’s a lot of stuff at the bottom!

Megan Hall: Interesting, what exactly is this “stuff”?

Hamid Torabzadeh: There’s all sorts of things, like decaying plants, dead animals, poop from shrimp and flies, and other debris carried in by rivers and wind.

Soren Brothers: You can imagine it’s all this really nice, tasty food for bacteria.

Megan Hall: What does that have to do with greenhouse gas emissions coming out of the lake?

Emma Mejia: When bacteria eat the stuff at the bottom of the lake, they release carbon dioxide, just like you or I do when we break down our food.

Hamid Torabzadeh: And It turns out that when the lake bottom sediments are exposed to air, the bacteria have a much easier time scarfing down that organic muck.  As a result, they release more CO2.

Soren Brothers: When that lake dries up, it’s like you’re just opening it up as a buffet for all these organisms to eat it. And that’s what’s causing that CO2 to come out.

Megan Hall: So, when parts of the Great Salt Lake evaporate, it exposes the bottom of the lake bed to oxygen?

Emma Mejia: Right.

Megan Hall: And then, that oxygen makes it easier for bacteria to eat the organic matter, which releases carbon dioxide?

Hamid Torabzadeh: Exactly. On top of that, there’s also other stuff  at the bottom of the lake which gets exposed as it dries up.

Emma Mejia: Minerals and heavy metals like lead, mercury and arsenic have also settled on the lake floor

Hamid Torabzadeh: Which could be a problem for people’s health if there’s a dust storm.

Emma Mejia: And this is becoming more of an issue as the lake dries up. So far its area has decreased 50% since the mid-1800s.

Megan Hall: What can we do to stop this?

Emma Mejia: Soren says we have to  look into why the lake is drying up in the first place.

Soren Brothers: The big driver is really people consuming water.

Hamid Torabzadeh: Water directed away from the lake for agriculture is one of the main culprits here. 

Emma Mejia: A study found that more than 60% of water from rivers that lead to the lake is taken away. Most of it is used to grow things like hay and alfalfa to feed to cows.

Hamid Torabzadeh: So, legislation that regulates how much water gets taken from these rivers could make a big difference.

Emma Mejia: But, other forces are playing a role too. Global warming, and harder to predict factors like the amount of snowfall in the nearby mountains, are also impacting the size of the lake.

Megan Hall: Is the Great Salt Lake the only place where this is happening?

Emma Mejia: No.  Other lakes around the world are creating greenhouse gas emissions too.

Hamid Torabzadeh: And similar solutions could work. Protecting these bodies of water would help all of the animals and plants that depend on them, and reduce emissions!

Megan Hall: Got it!  Thanks Emma, and Hamid!

That’s it for today. You can find more information, or ask a question about the way your choices affect our planet, at askpossibly.org. You can also subscribe to Possibly wherever you get your podcasts or follow us on Instagram, Facebook, LinkedIn, X, or Bluesky at  “askpossibly”

Possibly is a co-production of Brown University’s Institute for Environment and Society, Brown’s Climate Solutions Initiative, and the Public’s Radio.

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