由 jpichiban 
尼泊尔珠穆朗玛峰地区的夏尔巴人村庄泰姆村在8月16日遭遇冰河湖决堤洪水，造成约60人流离失所，房屋和基础设施被毁。这次事件让村民开始担心家园的安全，因为气候变化导致冰川加速融化，冰河湖泛滥的风险越来越大。虽然当局已将一些危险湖泊列入名单，但泰姆村附近的两个小型冰河湖却并未受到监测。专家表示，喜马拉雅山脉存在大量未监测的冰河湖，一旦溃决，后果将不堪设想。村民呼吁当局采取措施，加强对冰河湖的监测和预警系统建设，以保护当地居民的生命财产安全。
Original Title: Climate change: Nepal Sherpas fear their homes may be washed away by floods
Summary: The village of Thame, a small Sherpa settlement at 3,800 meters (12,467ft) in Nepal’s Mount Everest region, is home to many record-breaking Sherpa climbers, including Tenzing Norgay, the man who first scaled Everest with explorer Edmund Hillary. But on August 16, an ice lake burst its banks, sending a torrent of icy water through the village, displacing about 60 people, destroying more than a dozen homes and guesthouses, and damaging a school and clinic. The event has left the village’s roughly 300 residents questioning whether it is safe to live there. While the incident caused no casualties, members of the Sherpa community say they are thankful the flooding occurred during the day, when everyone was awake and alerts were raised quickly. “If the flood had happened at night, probably 200 to 300 people would have died,” said Ang Tshering Sherpa, former president of the Nepal Mountaineering Association. “We are still in shock and we (villagers) are still crying while talking to each other,” said Yangji Doma Sherpa, who was born in Thame. “The bigger question is, is it safe enough to live here now? This flood has shown that we are now facing a much more dangerous situation, so there’s no sense of security.” Some residents of Thame have a nomadic lifestyle and move between different villages depending on the season. Villagers from other settlements further down the mountain were also affected. “Some parts of our village were washed away due to the flood… Luckily we managed to run uphill,” said Pasang Sherpa from Tok Tok village. “The river which had white foamy water had turned deep brown with giant boulders and rocks being thrown around,” he said. “It was so terrifying, the sound and the sight, I am still scared now. I took shelter in a nearby village and am considering whether I should return to Tok Tok.” Locals say that a lot of the risk could be mitigated if there was proper monitoring of ice lakes upstream from the settlements. They add that while there are a few lakes that have come to the attention of scientists and authorities, the rest have been neglected. At the same time, many villages don’t have any disaster preparedness measures in place. “Villages downstream from Imja Lake have been trained on how to escape when a flood comes,” said Doma Sherpa. “But in our village, there has been no such training.” There have been more than a dozen recorded glacial lake outburst floods in Nepal over the past 50 years, four of which happened in the Dudhkosi river basin, where Mount Everest is located. One of these, in 1985, happened in the area upstream from Thame. A massive avalanche then sent snow into Dig Tsho glacial lake, triggering a wave that breached the dam. The subsequent flood destroyed a hydroelectric power station downstream, causing damage estimated at more than $3m.
The lack of monitoring is not unique to Thame. The Himalayas are home to thousands of glaciers and glacial lakes but only a handful of them are monitored and have flood-warning systems installed in the Everest region. Meanwhile, global warming is accelerating glacier melt, which could cause lakes to overfill and burst their banks. A 2021 study led by the University of Leeds found that Himalayan glaciers melted 10 times faster over the past decades than the average rate over the last 400 to 700 years, when the glaciers were expanding. Another study published in Nature in 2022 found that the Khumbu Glacier, located beneath Everest, might have lost half its ice volume since the 1990s due to climate warming. Imja Lake, located beneath Everest, was drained in 2016 because officials found it was at risk of overflowing and flooding settlements, trekking routes and bridges downstream. But scientists have found that a number of new lakes have formed in recent years while others have expanded and merged into larger ones. The rapid retreat of glaciers has destabilised the local landscape, leading to an increase in landslides and avalanches. Ice and rock debris have been flowing into lakes, which could lead to outburst floods, further compounding the risks. Authorities have flagged about 20 glacial lakes as dangerous in the Nepalese Himalayas but the two lakes that burst their banks on August 16 were neither on the list nor monitored by officials. “They were the smallest glacial lakes, nobody was concerned about them, but the damage was so huge,” said Ang Tshering Sherpa. “Imagine what would happen if a bigger glacial lake bursts. There are many such lakes in the Everest region,” he said. Officials from Nepal’s Disaster Risk Reduction and Management Authority (NDRRMA) conducted a helicopter inspection and found five small glacial lakes near the source of the flood. One had partially burst, while another burst completely. “It means the other three lakes in the same location could burst in the same way any time,” said Yangji Doma Sherpa. “Now people know about it, they don’t feel safe anymore. We are particularly concerned for older people as they are not mobile.”
The impacts of global warming on the glaciers and lakes in the Himalayas have become more apparent since then – locals say some of the damage from the flooding is now irreversible. The Thame river used to flow on the left side of the Khumbu valley but the flood on Friday diverted its flow. It now runs straight through the village, swallowing up nearly half of its land. “The rest of the land is now covered with rubble and debris,” said Yangji Doma Sherpa. “This is different from rebuilding houses destroyed by an earthquake. What can you build on when you don’t have the land anymore?” The flooding also damaged the reservoir of the only hydroelectric power station that provided electricity to the area. The disaster led to the deposition of silt and debris in the reservoir, causing the power station to shut down. “As a result, there is no electricity and the telecommunication system has also gone down because of the power outage,” said Mingma Sherpa, president of a youth club in Namche, a major tourist destination near Thame. “The region has been cut off from the outside world since the disaster. It’s terrifying,” he said. “We were always concerned about the slow impacts of climate change, like dwindling water resources, but this disaster shows how insecure and vulnerable we are.” Government officials are aware of the local communities’ concerns. Anil Pokhrel, chief of Nepal’s Disaster Risk Reduction and Management Authority, says the agency is now putting together a team of experts who will “assess the risk posed by the three remaining lakes upstream of Thame and see if the settlements downstream are safe to live in”. “We are also working to reduce the disaster risk in the area,” she added. However, members of the local Sherpa community say that over the years they have seen more talk than action when it comes to addressing the risk of glacial lake outburst floods. “We have heard grand plans, especially during meetings, but they are quickly forgotten,” said Yangji Doma Sherpa. “But we cannot forget the consequences of this flood, and other lakes are lurking out there, waiting to wreak havoc on us.”
Original article: https://www.bbc.com/zhongwen/simp/science-69284758?at_medium=RSS&at_campaign=KARANGA