NEW DELHI (AP) — Climbing to the roof of the world is becoming less predictable and possibly more dangerous, scientists say, as climate change brings warmer temperatures that may eat through the ice and snow on Mount Everest.
Nepal was left reeling when a sudden ice avalanche slammed down onto a group of Sherpa guides on Friday and killed 16 in the deadliest single disaster on Everest. While it is impossible to link any single event to long-term changes in the global climate, scientists say the future will likely hold more such dangers in high-altitude regions.
Avalanches of snow, rock or ice could increase. Climbing and trekking terrains would become unsteady. Glaciers may be more unpredictable. Storms will become more erratic, and the Himalayas in particular could see more snow as warming oceans send more moisture into the air for the annual Indian monsoon that showers the 2,400-kilometer (1,500-mile) mountain range.
Friday's disaster occurred at the Khumbu Icefall, long recognized as one of Everest's most dangerous spots, as the edge of the slow-moving glacier is known to crack, cave and send huge chunks of ice tumbling without warning.
"It's Mother Nature who calls the shots," Tim Rippel, an expedition leader, said in a blog post from Everest base camp as many of the 400 Sherpa guides were leaving, demanding better government compensation for the high risks they take in helping climbing companies ferry rich tourists up the peak. "The mountain has been deteriorating rapidly in the past three years due to global warming, and the breakdown in the Khumbu Icefall is dramatic," he said. "We need to learn more about what is going on up there."
There is nothing to prove the icefall was behaving unusually on Friday. But scientists say mountaineers should assume that everything is now in flux.
What makes the situation so risky, scientists say, is the uncertainty itself. While scientists are sure things are changing, they're not entirely sure how. Much of the evidence is anecdotal, and there isn't enough data or decades of scientific observation to draw solid conclusions. Rigorous glacier studies have only begun in the Himalayas in the last decade, and no one is studying snow patterns on a large scale, Nepalese glaciologist Rijan Bhakta Kayastha at Kathmandu University said.
Meanwhile, as global temperatures have gone up 0.75 degrees C (1.4 degrees F) in the last century, according to the International Panel on Climate Change, studies show the Himalayas warming at a rate up to three times as high.
"You can be sure that if the climate is changing — and it is — then glaciers are changing and the danger is shifting," said U.S. hydrologist Jeff Kargel of the University of Arizona who is leading a global project to measure and map the tens of thousands of Himalayan glaciers through satellite data. "It doesn't necessarily mean it's getting worse, it just means you don't know."
Kargel said population in the vicinity also plays a role. "The more people you have living or trekking in the mountains in seemingly blind disregard for a changing hazard environment, the more catastrophes you'll have," he said Wednesday in a telephone interview.