Atop the 20,310-foot Denali in Alaska will find stunning glacier, incredible views and poop. Lots of poop. Since 1906, people have attempted to summit the peak leaving behind tons of feces on the mountain. Now, reports Elizabeth Weise at USA Today, that mountain of waste threatens to be unleashed as climate change warms the mountain and opens literal poop shoots in the surface of the glaciers.

The problem of poop on Denali, the highest mountain in North America, grown over the years. For much of the 20th Century, climbing the mountain was reserved for scientists and elite explorers who pioneered many of the routes to the top. By the late 1970s, however, the climb had become more accessible for adventurous amateurs, with 680 climbers attempting to summit in 1979. That number has steadily grown, and last year over 1,100 climbers took part in expeditions up the mountain, about half joining a guided expedition.

The problem is, climbing Denali is not a day trip. On average, climbers spend 16 to 18 days on the mountain, acclimating at lower elevations and ferrying gear up to progressively higher camps before attempting the summit. All those people spending all that time on the mountain means lots of poop, about two tons per year.

Weise reports that the Park Service issued a rule last year requiring climbers to pack out any waste produced below 14,000 feet, and many guide companies are now voluntarily removing all waste on the mountain. But that still leaves behind an estimated 66 tons of poo that has been deposited along the mountain's most popular routes.

In the past, people thought that leaving the stuff in pits dug into the Kahiltna glacier or tossing it into deep ice crevasses would naturally eliminate it—the glaciers, they assumed, would keep the poo locked deep within their icy bowels and eventually pulverize it.

But research from NPS glaciologist Michael Loso, who has researched the fecal fiasco on the mountain for the last decade, tells Weise that’s not the case at all. His experiments (we choose not to go into detail), show that the poo does not get ground up, but flows down the glacier and eventually pops up to the surface at lower elevations, where it can contaminate streams, rivers and lakes.

“The waste will emerge at the surface not very different from when it was buried. It will be smushed and have been frozen and be really wet,” he tells Weise. “It will be biologically active, so the E. coli that was in the waste when it was buried will be alive and well. We expect it to still smell bad and look bad.”

Warming temperatures in Alaska, which has seen record highs already this month including a 70-degree day in the southeastern part of the state, is increasing the rate of melting on the surface of the glacier. Loso expects that the warming will cause the historical heaps of poo from the lower camps to start popping out the glacier soon, even as early as this year. He estimates that it will take another 200 to 300 years for feces higher up on the mountain to make its way down, meaning the contamination is a long-term problem.

Climate change and melting ice are causing an even more grisly scene on Nepal’s Mount Everest, the highest peak in the world. In the last century, over 200 people have died on the mountain, and most of the bodies were not recovered. It was believed that the remains would stay entombed in the ice and snow in the upper reaches of the mountain, but Navin Singh Khadka at the BBC reports that’s no longer the case. Sherpa mountaineering guides in the Everest region are reporting that hands and feet of dead climbers are emerging near mountaineering camps and entire bodies are appearing from the ice. While China, which controls the north side of the mountain, has begun removing the bodies in its territory, the guides say the Nepalese government needs to get involved in helping to remove the bodies from the southern routes.

Loso tells Weise that the Park Service does not have the manpower or money to try and clean up all the historical waste on the mountain. Luckily, he says the problem won’t get much worse. Mountaineers and guide services have embraced the leave no trace ethic and coming down the mountain with a full honey pot has become a badge of honor for climbers.