Top: Research indicates that only 37 to 49 percent of the glacier mass in the Himalayas will remain by the end of the century. Zakir Hossain Chowdhury / Undark
On an April morning in Sagarmatha National Park, a World Heritage Site in the Himalayas that includes Mount Everest, Domi Sherpa looks out at rocky black slopes that stand starkly against snow-capped mountains. In the past, these dark swaths would have also been covered with snow and ice. But, Sherpa says, the region’s melting glaciers have increasingly exposed the rocks beneath.
The Hindu Kush Himalayas have the world’s third largest concentration of glaciers, after the Arctic and the Antarctic. For this reason, they are sometimes referred to as the “Third Pole.” The region, though, has been warming faster than the global average. The glaciers are retreating, an erasure that has accelerated in the last few decades—and they may affect the water supply for communities both near and far.
According to a 2017 study published in Nature, by 2100, only 37 to 49 percent of glacier mass in the Himalayas will remain (compared with 2005 figures) if global temperatures rise 1.5 degrees Celsius above pre-industrial levels. Climate experts say that the changes will continue to alter the hydrological cycle in the region. “Glaciers and glacial lakes in the high mountains are very sensitive indicators of ongoing climate change,” wrote Sudeep Thakuri, a glaciologist at Tribhuvan University in Nepal, in an email to Undark. The Himalayas are such an important water source in Asia that they are sometimes referred to as the continent’s “water towers.”
Locals have noticed the differences over the years. Anu Sherpa started climbing Everest in 1970 when he was 24 years old; he retired in 1994, and now runs a shop at Namche Bazaar. Over the years, Anu Sherpa has noticed changes in the area’s climate. The seasons are less predictable, he said. The rain doesn’t come when expected, he added, and “this time, it should have been warm, but it’s not.” Throughout the region, the changes in water levels in local rivers will likely affect farming, sanitation, and fresh drinking water.
Even people far away will feel the effects of melting glaciers. And these changes will affect a lot of people: Rivers downstream supply water to nearly a fifth of the global population. The low-lying plains of Nepal and coastal regions of Bangladesh, for instance, will initially experience an increase in water levels, Thakuri said—a situation that would lead to more flooding. Over time, however, the situation might reverse. Because the glaciers would no longer hold as much ice and snow, he added, rivers downstream could receive less water in the dry seasons.
Domi Sherpa, standing with Mount Everest behind him, in Sagarmatha National Park, a region that has seen stark effects from climate change. In the past, the dark, rocky slopes in the background would have been covered with snow and ice. Zakir Hossain Chowdhury / Undark
Namche Bazaar, a small Himalayan town that is often referred to as the “gateway” to Mount Everest, sits approximately 11,500 feet above sea level. Locals say they have seen changes in the climate, including unpredictable precipitation and seasons. Zakir Hossain Chowdhury / Undark
The Himalayas are known as the “water towers” of Asia, and they have one of the highest concentrations of glaciers in the world. Climate scientists say that as the region warms and continues to lose its glaciers, hydrological cycles will also shift. Zakir Hossain Chowdhury / Undark
Anu Sherpa started climbing Everest in 1970. As a head guide, he visited the highest climbing camp, which sits about 26,000 feet above sea level. He says that he has witnessed firsthand many of the effects of climate change in the mountain region. Zakir Hossain Chowdhury / Undark Locals carry bottled water for tourists. Melting glaciers are expected to affect drinking water availability in the region. Because glaciers will no longer hold as much ice and snow, rivers downstream could receive less water in the dry seasons. Zakir Hossain Chowdhury / Undark
Children from the Nepalese village of Phakding play volleyball near the Dudh Kosi river—which carries water from the slopes of Mount Everest. According to UNICEF, children are at especially high risk from climate change, which will likely include river flooding. Zakir Hossain Chowdhury / UndarkThe name Dudh Kosi means “milk river,” so named for its white waters. It starts from the southern slopes of Mount Everest, feeding waterways downstream, including the Ganges River, which eventually empties into the Bay of Bengal.Zakir Hossain Chowdhury / UndarkAerial view of flooded homes in northern Bangladesh. In 2019, heavy rainfall flooded more than a quarter of the country, killing at least 114 people and affecting more than 7.6 million people. As glaciers melt in the Himalayas, such flooding may worsen.Zakir Hossain Chowdhury / UndarkIn Bangladesh, one of the most vulnerable countries to climate change, Manta people started living on boats after losing their land and homes to the Meghna River. It is estimated that one in every seven people in the country will be displaced by 2050.Zakir Hossain Chowdhury / UndarkA man walks along a river bank in Bangladesh. Rivers downstream from the Himalayas supply water to nearly a fifth of the world’s population; the effects of melting glaciers will be felt widely. Zakir Hossain Chowdhury / Undark
A family stands on their cropland, which has been eaten away by river erosion. Tons of water flow into the Bay of Bengal each year from the icy, sediment-laden water upstream. Although retreating glaciers will likely increase flooding initially, once they melt, areas including Bangladesh may experience droughts.Zakir Hossain Chowdhury / Undark
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