The terrible disaster in Nepal isn’t a one-off event, but a harbinger of things to come. There will be more catastrophes of this kind as mountainous regions around the world continue to warm fast, researchers warn. Better satellite images now show that an entire slope collapsed, with huge amounts of rock below and around the glacier also falling.
The rock and ice plummeted into the valley below, leading to a catastrophic wave of water and debris that swept down the river. It is still not entirely clear where such a huge volume of flood water came from, says Daniel Shugar at the University of Calgary in Canada. But it appears the falling rock and ice landed on other ice left by retreating glaciers.
Researchers are now discussing to what extent global heating contributed to this disaster in informal online forums. Davies, who has been studying glaciers in the area with Silwal and others, thinks climate change could have played a substantial part. Another factor could be the degrading of permafrost.
Ice in cracks helps hold rocky slopes together, and helps glaciers stick to the surfaces they flow over. The glacier involved in this disaster is just one of many retreating glaciers in the region. What’s more, the rate of retreat is increasing – it was 1.5 times higher from 2000 to 2023 than from 1964 to 2000.
The large glaciers on valley floors are relatively stable because of their size, but the smaller ones that flow down steep slopes and feed the valley glaciers are more vulnerable. In many cases, their lower parts are vanishing, disconnecting them from the valley glaciers. The fundamental problem is that the region is warming fast, at around 0.3°C per decade compared with a global average of under 0.1°C per decade, says Silwal.
The same is happening in other mountainous regions around the world, a phenomenon called elevation-dependent warming. The devastating wildfires in Europe demand urgent measures to make landscapes more resilient, but without action to reduce use of fossil fuels, the danger is only going to increase There are three reasons for this, says Mike Byrne at the University of St Andrews in the UK. Firstly, land areas in general warm faster than the seas.
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