A new report ties climate change to the glacier collapse that brought flooding to the Nepal-Tibet border, turning what would otherwise have been a natural hazard into a disaster. Researchers tracked the collapse of a glacier slope near the peak of Langtang Lirung, a mountain on Nepal’s side of the Himalayas, to rising temperatures, thinning ice, thawing ground and weak spots that developed over decades.
Floods and landslides swept through border towns and villages, sweeping away thousands of homes, damaging energy infrastructure and leaving thousands dead or missing. The death count now sits at roughly 1,400, per figures released on Wednesday, with the number of people still unaccounted for adjusted from 5,179 to 6,150.
The Collapse Traced Back
The disaster did not happen all at once. Researchers report that the Langtang Lirung glacier has been losing thickness at a rate of roughly half a metre per year (1.6ft), which could wear down existing cracks and raise the risk of collapse. Large amounts of meltwater built up early this year after heavy snow fell in October and November.
The combination of warm air, thinning ice and extra water created conditions that may have interacted to amplify the disaster, the study said. Climate change was a “destabilising factor acting on a pre-existing geological predisposition”, but it was not the only cause.
“Absolutely no doubt that human-induced climate change played a role here in the preconditioning of the disaster.”
Dr Friederike Otto, a climatologist at Imperial College London who co-authored the study, expressed the point that way. The World Weather Attribution study published on Thursday found that July and August temperatures in the region were roughly 1.5C (34.7F) above normal “due to human influence on the climate”.
The Force Of The Event
According to USGS data, the collapse registered as a magnitude 5.2 earthquake. The ice broke off and struck the bottom of the valley with sufficient force to generate shock waves through the ground.
The study said the disaster was the result of a “compound event” caused by rising temperatures, thinning glaciers, thawing permafrost and pre-existing geological weaknesses. Another co-author, Utrecht University mountain hydrologist Dr Walter Immerzeel, told reporters that the area was a “geologically vulnerable slope” that was “potentially weakened by the 2015 earthquake” and “destabilised further” by glacier and permafrost retreat.
The 2015 Quake
According to the study, the magnitude 2015 earthquake that hit the region may have weakened the underlying rock mass. A separate magnitude 7.8 quake set off a rock-ice avalanche, though officials were unable to confirm exactly how that event affected the glacier collapse that occurred last month.
A professor of earth sciences at Oxford University named Dr Mike Searle had earlier told the BBC that the glacier’s collapse was probably due to both climate change and gradual tectonic motion over time. The Langtang Lirung glacier, along with the rest of the Himalayas, has been steadily rising, making it “steeper and steeper” and “it’s inevitable that parts of it fall off”.
He said that the collapse of a large piece of glacier “in one go” was “very unusual”. Dr Simon Cook, a glacier expert with the University of Dundee, added that although it is difficult to link any individual event to climate change, “climate warming ultimately destabilises these high mountain environments”.
The Missing And The Dead
Floods and landslides devastated border towns and villages in Nepal and Tibet, leveling thousands of homes, damaging energy infrastructure and leaving thousands dead or missing. The count of lives lost has held steady at around 1,400, per figures issued on Wednesday.
Balendra Shah, who is making his first foreign trip since taking office as Nepal’s Prime Minister, is due to speak at the United Nations General Assembly in New York next week. He will address the recent disaster and the issue of climate justice. The Nepali government has asked other countries to work together on climate change, arguing that Nepal ranks among the world’s smallest contributors to greenhouse gas emissions even as it sits among those most vulnerable to the consequences of a warming planet.
What The Study Confirms
Other experts had previously told the BBC that climate change combined with long-term tectonic movement could have triggered the glacier collapse. The study now confirms their assessment.
The study said climate change was a “destabilising factor acting on a pre-existing geological predisposition”, but it was not the only cause of the disaster. The findings came as Nepali authorities significantly revised the number of people missing in the disaster from 5,179 to 6,150.
Researchers link the glacier collapse that caused the floods to climate change. Around 1,400 people died, with 6,150 still missing, showing the full weight of the disaster on people.
The Scientific Basis For The Case
Nepali leaders argue their nation bears a burden it did not cause, and the research now provides them with a factual foundation to make that argument.
The researchers make plain that climate change acted alone to bring about the collapse. Yet the record points toward a single conclusion: rising temperatures, thinning ice, and greater meltwater all pushed an already perilous state toward disaster.
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