DIFFICULT CLIMB: Trekking up and down this glacier-covered mountain takes about three weeks.

ROBERT HARDING/ALAMY STOCK PHOTO

 

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A Mountain of a Problem

Human waste buried by climbers of North America’s highest peak is about to resurface

AS YOU READ, THINK ABOUT how people can safely dispose of human waste during long treks through the wilderness.

Every year, more than 1,000 climbers head to Alaska to attempt a difficult and potentially dangerous feat—climbing Denali, the tallest mountain in North America. The grueling journey to the summit and back typically takes 18 to 21 days. Climbers must carry heavy packs up steep, frozen slopes while steering clear of deep crevasses. These cracks in the ice can plummet 120 meters (394 feet) straight down. During the ascent, climbers face extreme cold and high altitudes that can make it difficult to breathe. There’s also a challenge of a less-risky sort: where to go to the bathroom on an ice-covered mountain.

For decades, climbers dug holes called latrines in the ice or tossed their feces into crevasses, where it would never be seen again . . . or so they thought. Now scientists believe all that waste will soon reappear farther down the mountain. That’s because the glaciers that cover Denali are always on the move. Over time, the weight of the ice causes it to flow down the mountainside—carrying tons of left-behind poop with it.

Every year, more than 1,000 climbers head to Alaska to try a difficult and dangerous feat. They aim to climb Denali, the tallest mountain in North America. The tough journey to the summit and back usually takes 18 to 21 days. Climbers must carry heavy packs up steep, frozen slopes. They also must steer clear of deep crevasses. These cracks in the ice can drop 120 meters (394 feet) straight down. During the trek, climbers face extreme cold. High altitudes can make it hard to breathe. There’s also a less risky challenge. Where do you go to the bathroom on an ice-covered mountain?

For decades, climbers dug holes called latrines in the ice. They also tossed their feces into crevasses. There, it would never be seen again. At least, that’s what they thought. Now scientists believe all that waste will reappear soon, farther downhill. That’s because glaciers cover Denali, and they’re always moving. Over time, the weight of the ice causes it to flow down the mountain. And it’s carrying tons of left-behind poop with it.

POOP PROBLEM

Most Denali climbers follow the West Buttress route up the 72 kilometer (45 mile)-long Kahiltna glacier—one of five large glaciers on the mountain. “You could put an entire city on one of these glaciers, and the city would
look small compared to the size,” says Roger Robinson, a mountaineering ranger at Denali National Park and Preserve.

On the way to the summit, climbers typically stop at four or five camps. For years, climbers left their waste in holes in the ice there. They’d covered the latrines when they moved on, but that only hid the waste temporarily. “Surface snow would melt, and so within three weeks what you buried would be on the surface,” says Robinson.

Most Denali climbers follow the West Buttress route. It runs up the 72 kilometer (45 mile)-long Kahiltna glacier. That’s one of five large glaciers on the mountain. “You could put entire cities on one of these glaciers, and the city would look small compared to the size,” says Roger Robinson. He’s a mountaineering ranger at Denali National Park and Preserve.

Climbers usually stop at four or five camps on the way to the summit. For years, they left their waste in holes in the ice at camp. They covered the latrines when they moved on. But that only hid the waste for a while. “Surface snow would melt, and so within three weeks what you buried would be on the surface,” says Robinson.

NPS PHOTO

The reappearing poop wasn’t only disgusting, it also posed a health hazard. Human feces contain pathogens (see What’s in Poop?). These disease-causing microscopic agents, such as bacteria and viruses, contaminated the surrounding snow—the same snow that climbers melted for drinking water. As a result, many of them got sick.

Dismayed by how dirty the camps were, Robinson began developing a portable toilet. It would allow climbers to carry their waste off Denali. The Clean Mountain Can (CMC) is a small, lightweight container that can be strapped to a climber’s pack. Each one is lined with a biodegradable bag that will break down in the environment.

In 2007, the National Park Service began requiring all climbers to use CMCs at Denali’s highest and lowest camps. In between, they could empty the cans by throwing the bags into crevasses. The camps became much cleaner. But Robinson wondered: What would become of the tossed waste? He asked Michael Loso, a glaciologist at Wrangell-St. Elias National Park & Preserve in Alaska, to find out.

The reappearing poop wasn’t only disgusting. It also was a danger to health. Human feces contain pathogens (see What’s in Poop?). These are tiny, disease-causing agents, such as harmful bacteria and viruses. They can enter the surrounding snow. That’s the same snow that climbers must melt for drinking water. As a result, many climbers got sick.

Robinson was unhappy about the dirty camps. So he began developing a movable toilet. It would allow climbers to carry their waste off Denali. The Clean Mountain Can (CMC) is a small, lightweight container. It can be strapped to a climber’s pack. Each one is lined with a biodegradable bag that will break down in the environment.

In 2007, the National Park Service made a new rule. All climbers had to use CMCs at Denali’s highest and lowest camps. In between, they could throw the bags into crevasses to empty the cans. The camps became much cleaner. But Robinson wondered: What would happen to the tossed waste? He asked Michael Loso, a glaciologist at Wrangell-St. Elias National Park & Preserve in Alaska, to find out.

REAPPEARING WASTE

Loso estimated that over the past several decades, Denali climbers had left behind 73 tons of human waste on the Kahiltna glacier. And he was sure that poop would reappear below the climbing route in a remote area sometimes used by backcountry travelers.

To predict when this would happen, Loso and his team needed to know how fast the glacier was moving. They trekked up Denali and measured how fast snow accumulated and melted at different elevations along the glacier (see Anatomy of a Glacier). They also drove metal stakes into the ice and used GPS to track how far the stakes moved over time.

Loso figured out how much human waste was on the Kahiltna glacier. Over several decades, Denali climbers had left behind 73 tons. And Loso was sure that poop would reappear in an area below the climbing route. Backcountry travelers sometimes use this remote part of Denali.

Loso and his team needed to know how fast the glacier was moving. Then they could predict when the waste would reappear. To learn how fast snow fell and melted, they hiked up Denali. They took measurements at different places along the glacier (see Anatomy of a Glacier). They also drove metal stakes into the ice. Then they used GPS to track the stakes’ movement over time.

MENNO BOERMANS/AURORA PHOTOS

POOP SCOOP: A ranger shovels a bag of human feces into a crevasse.

According to the team’s calculations, waste would take between 71 and 206 years to reappear, depending on where and when it was buried. “Climbers first used the West Buttress route in the 1950s,” says Loso. “Sometime soon their poop ought to be emerging.” But the warming effects of climate change are melting glaciers at a faster rate. That means poop could resurface earlier than predicted.

The researchers also wanted to learn if poop buried in ice would eventually break down or if pathogens in it would die. The scientists froze some donated human feces samples in their lab. They buried others on the glacier and dug them up a year later. In both cases, the samples didn’t break down while frozen, and the pathogens remained active. “Poop’s not going to go away because you dumped it in the ice,” says Loso.

The team figured that waste would take between 71 and 206 years to reappear. This depends on where and when it was buried. “Climbers first used the West Buttress route in the 1950s,” says Loso. “Sometime soon their poop ought to be emerging.” But climate change is warming the planet. As a result, glaciers are melting faster. That means poop could reappear sooner than predicted.

The researchers also wanted to learn if poop buried in ice would change. Would it break down over time? Would the pathogens in it die? So people donated human feces samples, and the scientists froze some in their lab. They buried others on the glacier. A year later, they dug them up. All of the samples looked the same after being frozen, and the pathogens were still alive. “It’s not going to go away because you dumped it in the ice,” says Loso.

CARRYING IT OUT

Loso’s research influenced the passage of stricter regulations on Denali. Starting last year, climbers could dump their waste in only one crevasse high on the mountain. Below that, they had to carry it out. But many climbers choose not to toss poop into the crevasse. Robinson expects about three-quarters of this year’s climbers to carry out all their waste. “I’m proud to see how clean the mountain has gotten,” he says.

As more and more climbers commit to keeping Denali clean, Robinson believes that use of equipment such as CMCs should stop new waste from piling up. But with decades’ worth of frozen poo still traveling downhill, the past will be coming back to haunt the mountain for a long time to come.

Loso’s research helped get stronger rules passed on Denali. Starting last year, climbers could dump their waste in only one place. It’s a crevasse high on the mountain. Below that, they had to carry it out. But many climbers don’t toss poo into the crevasse. Robinson thinks about three-quarters of climbers will carry out all their waste this year. “I’m proud to see how clean the mountain has gotten,” he says.

More and more climbers want to keep Denali clean. As they use gear like CMCs, Robinson believes that new waste will stop piling up. But decades’ worth of frozen poop is still traveling downhill. So the past will be coming back to haunt the mountain for a long time. 

PLANNING AND CARRYING OUT INVESTIGATIONS: How did scientists gather data to understand the fate of human waste left on Denali?

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