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50,000 old photos in Golden are helping scientists answer new questions about climate change

American Alpine Club library's archive of images by early mountaineers holds clues for researchers documenting the retreat of glaciers worldwide

An American Alpine Club librarian shelves books mailed back from members across the United States. The club’s collection includes more than 21,000 books and 50,000 images of interest to climate researchers. (Joe Purtell, Special to The Colorado Sun)
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American Alpine Club Library Director Katie Sauter spends a lot of time in the climate-controlled special collections room, flipping through hundred-year-old photographs, black and white images of climbers posing in front of the world’s mountains and glaciers in the early 1900s.

While the library is primarily maintained for climbers and historians, there is another interested cohort: glacier scientists.

The Arapaho Glacier is the largest in Colorado and a key component of Boulder’s water supply. Over the last 100 years, it has receded dramatically, and climate researcher P. Thompson Davis worries it could disappear completely. (American Alpine Club)

Scientists periodically email the library, or even show up in Golden, looking for rare old photographs. Sauter says that while she has received requests for photos of the remote Ladakh region of India — and, closer to home, the Arapaho Glacier northwest of Nederland — they are largely focused on the same thing.

“Glaciers, mostly,” she says, “to see how much it’s melted.”

Early in the Alpine Club’s history, climbers were interested in photos of glaciers so they could see what obstacles faced them before they traveled to attempt a mountain. They used some of the earliest film cameras to document the valleys filled with ice. In 2019, scientists have a more pressing interest, and new equipment to match.

Ted Scambos, a senior research scientist at the Cooperative Institute for Research in Environmental Sciences, a University of Colorado and NOAA partnership, estimates the Arapaho Glacier has lost 75 percent of its ice in the last 100 years. To get an idea of the glacier’s range at the turn of the century, he turned to old photographs.

When climate researcher Ted Scambos was a young man, he didn’t see glacial science in his future. “I didn’t really care all that much about them, it wasn’t like I was on a quest all my life,” he says. “it turned out to be a great thing to work on because it’s an active system and it’s responding to climate change a lot.” (Provided photo)

“We probably used some of those photographs estimating the size of how the area of Arapaho Glacier has changed since the beginning of the 1900s, then moved on to satellite data more recently,” Scambos says.

When doing his own imagery, Scambos uses high-resolution images taken from different angles to construct a three dimensional model of the glacier’s surface. His team has used ground-penetrating radar to map the glacier’s internal workings. Still, when scientists want to establish a glacier’s historic range, they are left to search through old photos.

The AAC had been collecting records for almost 100 years before scientists started making requests. Founded in 1902, the AAC was a small and committed group of climbers. The library was established soon after.

“They started collecting stuff to exchange with each other, so they could share information on mountainous regions around the world,” Sauter says. In 1911, the first collection of photos was donated to the club.

As decades passed, the catalog grew as members donated or willed their collections to the club.  

“I think we’re the largest mountaineering library in the world, but we haven’t confirmed it,” Sauter says. The Alpine Club in London claims it has the largest alpine library in the world. “They have 18,000 items,” Sauter says. “So if you go by what they say, then we are the largest, because our circulating collection alone is larger than theirs, our Central Asia collection is over 30,000.” Sauter estimates that the AAC library has over 50,000 items.

The American Alpine Club’s special collections include books full of old mountain photographs. When the library was housed in New York, club members would look through the pictures before planning trips to Colorado. (Joe Purtell, Special to The Colorado Sun)

While the AAC Library has an extensive collection of maps, photos and even board games from Asia, they also maintain collections of photos made closer to home. One, the Mountainview Collection, is of particular interest to glacial scientists. “It’s all pasted onto cardboard, and it’s the United States and Canada, 1890s to mid 1920s,” Sauter says.

Beginning only a few years after the invention of the modern film camera, the Mountainview Collection offers some of the earliest available images of North American glaciers. At the time, the photographers would not have suspected their images would one day be used to recall ice flows that traversed entire ranges — ice that today appears as lakes in photos taken from the same vantage points.

P. Thompson Davis has been studying glaciers since graduate school at the University of Colorado. Although he now lives in Massachusetts, he stopped by the AAC library while visiting his brother, and was able to find several old photographs that helped him determine the position of Colorado’s Arapaho glacier in the early 1900s. (Provided photo)

“I think it was just, ‘Look at the view!’ I don’t think anyone was thinking about the environment back then,” Sauter says. “There would be naturalists, and they would document the plant life and that sort of thing. A lot of them were geologists, so we have some rock samples that they collected.”

P. Thompson Davis is one of the scientists finding a new use for the historic photos. Davis, who has been studying the historic ranges of Colorado glaciers for decades, first encountered the subject as a grad student at CU. He decided to study the glaciers close to home, in Colorado’s mountain valleys, and collected a series of sediment cores, cylindrical samples taken from lake beds that scientist use to find data on climate history. The Arapaho Glacier, a key water source for Boulder, caught his attention.

“I’m interested if the Arapaho Glacier might have disappeared in the early Holocene, which was the warmest time of the last 12,000 years,” Davis says. “To put that in context, I’m trying to get some historical photographs, which are pretty hard to find, as it turns out, for Colorado.”

Davis conducts his research primarily with radiocarbon dating of moraines — rocky glacial debris — used to determine the glacier’s position over thousands of years, but he jumped at the opportunity to also use century-old photographs. Sauter showed Davis through the archives, and was able to find a few photos that fit his criteria. A lot has changed since the pictures were taken.

“That was a much colder time. The Arapaho Glacier was much more extensive in the early part of the last century than it is now,” Davis says. “Of course that’s a concern.”

The Arapaho Glacier is the largest in Colorado. Climate researcher P. Thompson Davis is testing a hypothesis that the glacier might have disappeared before, perhaps 8,000 years ago. (American Alpine Club photo)

So far, Davis’ research has shown that the furthest the Arapaho Glacier reached down valley in the last 10,000 years was in the 1800s. He’s also testing another hypothesis, and believes the glacier might have disappeared entirely around 8,000 years ago.

“If that glacier disappeared 8,000 years ago, let’s say, there’s every reason to believe it could disappear again. Temperatures are warmer now than they were back then,” Davis says.

Scambos is not convinced that the Arapaho Glacier will completely disappear without several degrees of warming. He credits the steep cliffs shading the glacier’s upper reaches and the avalanches that feed it all winter. But he doesn’t think the Arapaho will return to its earlier form anytime soon.

“It’s going to take extremely warm conditions for that to disappear as a snowbank. But having it as a glacier that actually flows down the valley, it’ll never get back to that point,” Scambos says.

“People can change the place where they live, and it’s not always for the better, and it’s hard to put it back the way it was,” he adds. “There’s an increasing social will towards keeping things the way they were, because once they’re gone they’re gone. Arapaho Glacier used to be this beautiful alpine vista, now it’s all rubble and rock. It’s dusty.”  

In the 1920s, people could take a train to the Arapaho Glacier from Boulder for a tour and lunch. A century later, the glacier is little more than a snowbank.

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