China-Nepal border flash flood must galvanise climate change cooperation

The immediate cause of the disaster remains the subject of debate. But there seems little doubt of the involvement of climate change in the separation of a large chunk of rock and ice from a high-altitude Himalayan glacier before it slid into a valley more than a kilometre below and triggered the lethal torrent.

Accelerated melting and receding of glaciers is linked to global warming. The Himalayas are especially vulnerable because their steep slopes have a large amount of permafrost – rock and soil sometimes frozen for centuries – which can start to melt with rising temperatures. Even a minor earthquake can accelerate destabilisation.

This is not only happening in the Himalayas. One recent incident, in particular, illustrates the importance and urgency of developing early warning mechanisms. In May last year, a large part of the Birch glacier in the Lotschen valley of the Swiss Alps became detached and triggered a catastrophic rock-ice avalanche that obliterated most of the village of Blatten. Thanks to prior surveillance and hazard assessment, the local population had been evacuated just nine days earlier. Scientists warn that without reliable early warning systems, such incidents could happen elsewhere with catastrophic results.

The current tragedy unfolded on Wednesday morning when a massive landslide triggered a fast-moving debris flow. According to state broadcaster CCTV, the torrent was travelling at up to 200km/h (124mph) and generated a wall of water as high as 15 metres (50 feet) when it slammed into the Gyirong Port border checkpoint between the Tibet autonomous region and Nepal.

Ordering all-out search, rescue and relief operations, President Xi said that the most urgent task was doing everything possible to find missing individuals, evacuate residents at risk and treat the injured to minimise casualties.