Nepal flood destruction shows “limits to adaptation”, scientists say

There is very little authorities in Nepal could have done to prevent the deaths and devastation caused by the flash flood on its border with Tibet in late August, scientists with the World Weather Attribution (WWA) group have said.

Launching a study that highlighted the role of climate change in causing the glacial rock and ice collapse that triggered the Himalayan flood, WWA co-founder Friederike Otto told reporters that “no amount of local adaptation can fully shield vulnerable people downstream from this scale of destruction”.

There is very little authorities in Nepal could have done to prevent the deaths and devastation caused by the flash flood on its border with Tibet in late August, scientists with the World Weather Attribution (WWA) group have said.

Launching a study that highlighted the role of climate change in causing the glacial rock and ice collapse that triggered the Himalayan flood, WWA co-founder Friederike Otto told reporters that “no amount of local adaptation can fully shield vulnerable people downstream from this scale of destruction”.

The findings released on Thursday are likely to strengthen Nepal’s case for emergency support from the UN’s Fund for Responding to Loss and Damage. Its board members met informally on Wednesday to discuss whether to grant the country a maximum of $20 million towards its estimated $4.8 billion cost of recovery and reconstruction, but no decision has yet been taken.

Nepal’s foreign minister Shisir Khanal told Climate Home News last week that the destructive flood was “exactly the kind of climate-driven catastrophe the Fund was created to address”.

Hard to predict

The WWA study found that rock-ice avalanches are very hard to predict and that moving people out of areas vulnerable to such floods is difficult as their livelihoods revolve around the rivers along which the floods travel.

The recent disaster began on the morning of August 26, when an avalanche started falling beneath a glacier. This caused huge amounts of rocks and glacier ice to fall over a kilometre to a valley floor, where they then picked up more rock and ice and became a flood of debris heading downhill and downstream along the border of Nepal and Tibet.

The torrent entered the narrow Lhende Khola gorge and crashed through the busy Gyirong port border crossing at 170 kilometres an hour. It continued many kilometres downstream before eventually turning from rock and ice to water and slowing down.

The flood swept through villages, roads, bridges and hydropower stations, killing over 1,300 people in Nepal with more than 5,000 still missing. The flood also killed at least 40 people in Chinese-run Tibet.

Those on higher ground away from the river mainly survived but the flood’s speed meant that many people received no warning to seek higher ground or shelter.

While Nepal has early warning systems for flooding caused by rain and glacial lake outbursts, the WWA study noted that rock-ice avalanches are complex and understudied, with methods to monitor them still being explored.

Co-author Walter Immerzeel, mountain hydrology professor at Utrecht University, told journalists that with current methods, the disaster could not have been predicted.

But, he said, in the future it may be possible to use remote sensing techniques to analyse glaciers and rocks to generate a warning before a collapse occurs.

A technique called radar interferometry can detect hotspots which should be monitored with field-based sensors and drones, he said, adding that early warning systems could be installed in these areas using seismometers, water-level measurements and CCTV.

Because doing this for thousands of glaciers across the Himalayas would be difficult, authorities could monitor only the rock and ice faces that are a danger to the river valleys with the most people and infrastructure in them, he added. But this would still require lots of investment together with international collaboration and coordination, he warned.

The study found that another potential adaptation strategy – restricting development in flood-prone river valleys – is socially, economically and politically difficult.

The scientists said habitable land is scarce in these steep river valleys and economic activities like transport and hydropower generation are dependent on the river itself.

Madhab Uprety, a Nepali scientist from the Red Cross Red Crescent Climate Centre, said that, while new development should assess the risks of floods, many existing communities and buildings are already at risk.

Loss and damage

Otto said the flood should be discussed in the context of loss and damage as “there is no doubt that climate change is one of the drivers” and “it’s also one of the types of events that are absolutely outside of the limits we can possibly adapt to”.

As well as the deaths, a Nepali government’s assessment has found that a large amount of infrastructure was damaged, including more than 7,500 homes, 105 bridges, 48 public buildings, 47 cultural heritage assets, 18 schools, 13 hydropower facilities, seven health facilities, and numerous shops, hotels, restaurants, irrigation systems and farms. Over 30,000 people were affected.

Developing countries have called for the loss and damage fund’s board to hold an emergency meeting to discuss how to respond to Nepal’s request for funding. Instead of a full board meeting though, board members met only informally and online on Wednesday, Climate Home News understands. A source with knowledge of discussions said the informal nature of the meeting meant they were not able to take decisions or agree on next steps, which have been left up to the board’s co-chairs.

Speaking before that meeting started, Nepali climate negotiator Manjeet Dhakal said he had “heard of an extremely positive response” to Nepal’s request from board members. “Hopefully there will be something – a decision that the fund will do for exactly the reason that the fund was established,” he said.

Ajay Mathur, former Indian climate negotiator and now head of The Energy and Resources Institute in New Delhi, told a separate press briefing on Wednesday that the Nepal flood disaster would push loss and damage higher up the agenda of international climate talks, particularly if the United Nations Secretary-General decides to champion the cause at the UN General Assembly in New York next week.

Murat Kurum, Turkish environment minister and president-designate of COP31, told Climate Home News last week that he would be “pleased” if the fund could support Nepal and that he will keep calling in every speech for countries to give money to the loss and damage fund.

Jennifer Morgan, former German climate envoy and now a senior fellow at the Fletcher School of Law and Diplomacy, called for the loss and damage fund – which currently has around $630 million in contributions – to be topped up with new pledges from governments as well as solidarity levies on things like luxury air travel, super-rich individuals and fossil fuel firms’ windfall profits.