When Edmund Hillary and Tenzing Norgay reached the summit of Mount Everest 60 years ago Wednesday, the mountaineers gazed over a view from the top of the world that had never been seen before.
The view has changed since that historic day. Pollution and rising mountain temperatures are relentlessly shearing away at the Himalayas’ frozen façade. Photographs taken around the time of the 1953 expedition show hulking ridges of ice that have since shrunk or disappeared.
Glaciers and snow are melting throughout the sprawling mountain range, which stretches across India, Pakistan, Afghanistan, Bhutan, Nepal, and Tibetan China. The waning glaciers are leaving precarious mountainside lakes of cyan blue water in their wake.
So much of the ice has disappeared that climbers following in Hillary and Norgay’s footsteps this spring climbing season, including two octogenarians, are encountering rockier cliff faces that are less stable than the ice that was scaled by the mountain’s first conquerors.
“There is a big change compared to when I first climbed,” says Apa Sherpa, 53, a retired Nepalese mountain guide who scaled Mount Everest a record-setting 21 times from 1990 until 2011. He has lived in Utah since 2006 but still visits Nepal every spring or fall, where he participates in treks and climate campaigns.
He says the landscape changes can be clearly seen from the summit of Everest, which by most measures is the tallest mountain in the world. “It used to be more snow and ice, but now it’s more rock,” Sherpa said. “It’s very dangerous for climbing.”
Soot produced by stoves, power plants, brick kilns, and vehicles throughout the region is wafting up and across the Himalayas. The black carbon is settling on glaciers, which appears to be hastening their demise by absorbing heat from the sun.
Temperature increases are greatest in the Himalayas’ higher altitudes, but the most visible changes are occurring at the lower elevations. The mountain range’s white skirt is being hoisted, exposing rocks and hinting at the scale of global glacial losses.
A study published in Science this month used data from two NASA satellite projects to calculate that the world’s glaciers contain just 1 percent of the ice on the planet’s surface, but that between 2003 and 2009 glacial melting contributed 29 percent of the rise of the world’s seas. (Melting ice sheets in Greenland and Antarctica are contributing about the same amount to sea-level rise. The other 40 percent or so is the result of oceans expanding as they heat up and from groundwater that’s being pumped out and winding up in the seas.)
The decline in Himalayan glaciers is a threat to more than a billion people who live downstream. Rain that helps recharge the region’s rivers is scant during most of the year, falling mostly during the late summer monsoon season. Gradually melting glaciers keep the rivers flowing.
“The current trends of glacial melts suggest that the Ganga, Indus, Brahmaputra, and other rivers that crisscross the northern Indian plain could likely become seasonal rivers in the near future,” says Rajendra Pachauri, chair of the Intergovernmental Panel on Climate Change.
On Everest and in the surrounding Sagarmatha National Park, more than one-eighth of the glacial ice appears to have melted since the summit was first reached in 1953. That’s a preliminary finding from an analysis of historical satellite images and other data presented this month by Sudeep Thakuri, a Nepalese Ph.D. candidate at the University of Milan, at an American Geophysical Union meeting in Mexico.
The research reveals that glaciers on and around Everest have shrunk 13 percent since some of the earliest satellite images were taken 50 years ago. The mountain’s lowest bands of snow appear to have shifted 590 feet upward during the same period.