Additional Coverage:
- Climate change made deadly Nepal glacier and rock collapse more likely, according to analysis (nbcnews.com)
A recent report highlights how human-driven climate change likely contributed to the devastating Himalayan landslide and subsequent flooding in Nepal last month, which claimed over 1,300 lives and left thousands missing. The World Weather Attribution analysis, released Thursday, indicates that warming temperatures have thinned glaciers and thawed mountain permafrost, factors that probably weakened the slope and triggered the catastrophic collapse near Nepal’s border with China.
While the report acknowledges that climate change was not the sole cause-pointing out that a significant earthquake in 2015 may have already compromised the rock-the long-term effects of rising temperatures on mountain stability are clear. Ben Clarke, a climate researcher involved in the study, emphasized that although the disaster was not directly caused by an extreme weather event, the influence of climate change is evident in gradual shifts affecting the region’s geology.
The collapse unleashed a destructive mix of water, ice, boulders, and sediment that swept through communities along the Trishuli River corridor, causing billions of dollars in damages. Scientists warn that as Himalayan glaciers retreat and permafrost thaws, the very foundations holding fractured mountain rock together weaken. This not only alters weather patterns but also increases the risk of landslides and slope failures in areas where many communities reside in narrow river valleys.
One key finding of the report is the upward shift of the freezing line by approximately 100 meters per decade, exposing rock formations to prolonged thawing periods. This thawing compromises the ice that binds rocks, making slopes more vulnerable to collapse. Jakob Steiner, a geoscientist familiar with the region, noted that ground once permanently frozen at elevations around 5,000 meters is now subject to seasonal thawing, further destabilizing the terrain.
Glacier retreat also plays a critical role. The Langtang Lirung glacier, near the disaster site, has receded about half a kilometer since the 1990s, unveiling previously ice-covered rock.
Across the Himalayas, glaciers are thinning at rates exceeding half a meter annually. With over 63,000 glaciers feeding major Asian rivers, their decline threatens water security for billions.
Studies estimate that from 2000 to 2019, glaciers lost ice mass equivalent to tens of thousands of Great Pyramids of Giza annually.
The weeks preceding the August 26 event were notably warm, setting records for the hottest July and August in the region. Friederike Otto, co-author of the report, stressed that while geological factors like earthquakes weaken bedrock, climate change intensifies the processes that undermine mountain stability.
The disaster also underscores the limitations of current adaptation strategies. Nepal’s disaster warning systems and risk reduction plans were overwhelmed by the scale and suddenness of the collapse. Unlike floods caused by rainfall, which can sometimes be forecast days in advance, such rapid slope failures in remote high-altitude areas remain difficult to predict.
Otto highlighted that mountain communities are especially vulnerable to climate impacts, as even minor temperature increases can destabilize the land. Although improved monitoring and early warning systems may help mitigate some risks, the report cautions that there are inherent limits to adaptation where infrastructure and settlements cluster along fragile river valleys.
Given that glaciers and permafrost respond slowly to temperature changes, some degree of mountain destabilization is already underway. The report concludes with a stark warning: the most effective way to reduce future risks in the Himalayas is to rapidly curb fossil fuel emissions driving global warming. Without urgent action, events like Nepal’s recent tragedy are likely to become more frequent and severe.