Climate and the Cryosphere with Dr. Caitlyn Florentine

A conversation with Dr. Caitlyn Florentine, research physical scientist with the US Geological Survey, who studies snow and ice in Glacier. This episode was recorded in May 2023.

Glacier Conservancy: https://glacier.org/headwaters Frank Waln music: https://www.instagram.com/frankwaln/ Stella Nall art: https://www.instagram.com/stella.nall/

Overview of the park’s glaciers: https://www.nps.gov/glac/learn/nature/glaciersoverview.htm

---

TRANSCRIPT:

---

Lacy Kowalski: Headwaters is supported by the Glacier National Park Conservancy.

Peri Sasnett: You're listening to Headwaters, a show from the icy mountains of northwest Montana about how Glacier National Park is connected to everything else. My name is Peri, and this episode is an interview that my co-host Daniel did with glaciologist Dr. Caitlyn Florentine—about how the U.S. Geological Survey studies the park's glaciers. This episode is part of a series of conversations we've been having with a wide variety of climate change experts. These episodes don't have to be listened to in any order. Each one stands on its own. And they all focus on a particular aspect of the way the world is being altered by the burning of fossil fuels. Over the past century and a half, human activity has released enough greenhouse gases to warm the Earth's climate over one degree Celsius, with only more warming on the way. Throughout 2023, Daniel sat down with experts to talk about how that warming is altering Glacier National Park, our lives and our futures.

[background drum and bass music builds]

Peri: Glaciers are the park's namesake. So digging into the details of the science around them feels like the heart of the park's story. I will say this is a fairly wonky and detailed conversation about glacier science. I studied geology, so I loved it. But I think no matter your background, you'll find it thought provoking.

[music concludes]

Daniel Lombardi: Dr. Caitlyn Florentine, welcome to Headwaters.

Caitlyn Florentine: Hello. Thank you for having me.

Daniel: Can you introduce yourself? What's your job? What do you do?

Caitlyn: Yeah. My name is Caitlyn Florentine, and I work as a glaciologist for the U.S. Geological Survey. I'm a research scientist.

Daniel: So what have you been up to for the past couple of days?

Caitlyn: I've been here in the park doing fieldwork on Sperry Glacier.

Daniel: So you were up up in the mountains for the past couple of days?

Caitlyn: Yes.

Daniel: That's exciting.

Caitlyn: Yes, We had excellent weather.

Daniel: Do you think of yourself as a glaciologist or you study the cryosphere? How do you describe what you do?

Caitlyn: I consider myself a cryosphere scientist, and the cryosphere is the portion of the earth that is frozen. So anything involving frozen water: land, ice, sea ice, permafrost, seasonal snow. So I'm a glaciologist, and I think of it from sort of a geophysical perspective.

Daniel: You approach the study of the cryosphere, you approach glaciology from a very quantitative way. What does that mean?

Caitlyn: Correct. We are interested in being very sort of precise with the numbers. So quantifying the amount of water that's entering and exiting the glacier system, for example. So rather than having a sort of description of the quality of what's happening, we also strive to put numbers to that so that we can start to be a bit more precise and exact in our understanding, which then enables us to connect to other studies and sort of systems of the of the earth.

Daniel: So what made you want to get into this field? How did you get started in the study of the cryosphere?

Caitlyn: I really love the mountains and to be in the mountains and there is a plethora of snow and ice in mountain environments. So I studied geology as an undergrad at Colorado College, and I was really fascinated by earth processes and I knew I wanted to study something on timescales that were relevant to humans. And so I made a choice for graduate school between volcanology and glaciology. And then my sort of recreational interests led to me choosing glaciology ultimately.

Daniel: Oh, that's super interesting. Cool. Yeah, because you could have studied a geology that, you know, spans millions or even billions of years, but you had a desire to keep it on a human scale or closer to a human scale anyway.

Caitlyn: Exactly. My colleagues who study seasonal snow, for example, are inspecting processes that are happening over the timescale of seconds or or hours or days. And it's sort of that opportunity to toggle the window of time that we're considering, I think really captivated me and drew me to the cryosphere.

Daniel: Oh, that's okay. That plus you want to go be able to go up into the mountains for work. So it's a good fit. Well, what makes your work important? Like, why does the cryosphere matter? Why do glaciers matter?

Caitlyn: The cryosphere right now is changing very quickly, relative to what we've observed in the last ten, twemty, fifty, a hundred years. And so that rate of change makes it really important that we not only document the changes that are occurring and understand the sort of pace of that change relative to the historical context, but also that we understand how these systems are working. Because with the rapid change of the cryosphere, so changes to seasonal snow and changes to glaciers, there are consequences downstream. So one sort of motivating example of why glaciers are important is the meltwater that glaciers provide. So a glacier sitting on the landscape will have some discharge of meltwater during the late summer months, at least in this part of the world. And that delivery of meltwater during a time of year that would otherwise be quite dry can be really critical for the aquatic habitats and for sort of broader water resources.

Daniel: I'm hearing you say kind of two things in particular there. One of them is that studying the cryosphere is important because it's changing and it's an indicator of change. So it's helpful in understanding how the world is changing. But you're also saying glaciers and the cryosphere is made of water, and water is important to people and wildlife and everything. They're valuable for that reason. Is that right?

Caitlyn: Yes, exactly.

Daniel: So I don't know if you know this, Caitlyn, but historians think that maybe one of the first euro-Americans to document a glacier here was this military guy John Van Austell, in the 1870s. But the complication is that he didn't realize he was looking at a glacier when he was. And so it wasn't until like ten years later, he came back to the same area inside what is now the park with a geologist. And they're like, oh, that's a glacier. And so then this area starts to be known as a place with glaciers. Of course, the Native Americans, the Kootenai people, the Blackfeet people, they had words describing the ice of this place. They they knew this place was full of snow and glaciers and ice for a long time before that. All of this is kind of me building up to ask you, you know, like some people might be surprised that glaciers are kind of hard to spot, surprisingly. What do you think? I mean, is that does that feel right?

Caitlyn: Yeah. So a glacier as it's now defined, it gets trickier when the ice masses get smaller. So if you're in a landscape where, there's, you're looking down a valley, and particularly at a time of year when the seasonal snow is absent. And so you're just looking at bare rock and bare ice, it will probably be quite evident what is a glacier versus what is not. Also, if you're looking at a glacier that has a lot of evidence of motion. So if you're looking at the terminus of a tidewater glacier and there are giant chunks of ice calving off into the ocean, then the sort of, all of the criteria for defining a glacier—ice that moves—is really in your face and really evident. In a landscape like Glacier National Park, the glaciers are much smaller and you have to hike a lot further into the mountains to observe them. And this has been true for the last last several centuries, if not last many thousands of years. This landscape did have big valley filling glaciers, but that was up to tens of thousands of years ago, maybe 12,000 years ago.

Daniel: So to put that another way, if you go to Alaska or if you came to this area 12,000 years ago, you're going to notice some glaciers, like they're pretty obvious because they're huge chunks of jagged moving ice. But these days in this place, glaciers are covered by seasonal snow. They're covered in rocks. They're they're smaller. It's a more complicated thing to discern. So it's not surprising that visitors today, when they come to the park or scientists a century ago maybe weren't sure at first when they were looking at a glacier.

Caitlyn: Precisely.

Daniel: Well, let's get a definition out of the way, then. Really simply what what is a glacier?

Caitlyn: A glacier is a body of ice that moves.

Daniel: Okay, simple enough.

Caitlyn: And when we talk about glaciers as moving bodies of ice, it's important to understand that, like most of us interact with ice when it's stagnant and it isn't under sufficient stress to deform and flow. But ice is actually a vicious material. So a comparable material would be honey or ketchup. So glacier ice will deform when it's under pressure. So same is how you have to hit a ketchup bottle to get the ketchup to come out of the bottle. So we sort of have two components of glacier motion. One is the ice deformation, the sort of vicious, fluid motion that I just described. And then one is the the sliding of the ice over its b