Dr Eklabya Sharma: ‘Nepal Flood Is A Warning’

‘There needs to be a monitoring of glaciers in high altitude areas and one needs to check regularly how geological changes are taking place.’
‘We can mitigate that by regular monitoring but unfortunately, hardly any monitoring is happening.’
‘And without monitoring those higher altitudes of Himalayas, people are suffering.’

IMAGE: Damaged settlements in the flash flood caused by an outburst in the Bhote Koshi river in Nepal. Photograph: ANI Video Grab

The sudden flooding in Nepal has once again raised questions about the growing vulnerability of the Himalayas to climate- and glacier-related disasters.

To understand what triggered the latest event, the warning signs scientists should be looking for, and whether such disasters can be anticipated, Syed Firdaus Ashraf/Rediff spoke to Dr Eklabya Sharma, ecologist, strategic advisor and distinguished fellow at the Ashoke Trust for Research in Ecology and Environment.

A Padma Shri awardee, Dr Sharma has more than four decades of experience in sustainable mountain development and has worked extensively on Himalayan ecosystems, climate-change impacts, watershed management, biodiversity conservation and transboundary river basins.

He has also served as deputy director general at the International Centre for Integrated Mountain Development (ICIMOD) and held several other national and international positions focused on Himalayan science and policy.

Dr Sharma explains why the Nepal flood should not simply be viewed as an isolated natural disaster, how rising temperatures are making high-altitude glaciers and mountain slopes more unstable, and why better monitoring of glaciers, glacial lakes and river basins is urgently needed.

What do we know so far about what actually triggered this sudden flooding in Nepal?

The trigger is a huge glacier mass rock that has fallen apart. And with this a landslide was created from the Nepal side.

The (Bhote Koshi) river which is bordering Nepal and Tibet had a cascading effect that led to flooding.

Was an earthquake the reason, as some reports suggest?

No, an earthquake was not the reason as some reports had suggested earlier.

The earthquake-like situation was developed when this huge glacier rock fell, which was huge in size.

The impact resulted in tremors, but this was not an earthquake.

‘The Mountains Are Heating Much Faster’

There have been reports that a 2,000 feet wide chunk of glacier fell about one kilometre towards the valley. How accurate are these reports and what role did that collapse play in the flooding?

Yes, that is the case. It fell 7,000 feet, which is a huge fall, after which this whole incident (happened).

Why does this happen?

If you look at the Hindu Kush Himalayan region shared by eight countries (India, China, Afghanistan, Bhutan, Myanmar, Pakistan, Nepal and Bangladesh), there are many glacial lakes formed because the glaciers are melting.

The number of glacial lakes are distinctly increasing (which on sudden outburst can result in flooding).

In the 1990s it was around 3,000 or so, which increased to 4,500 or so by 2010 and by 2024 it has doubled to 8,000 glacial lakes.

What happened in Nepal was not due to glacial lake melting, because here a huge glacier mass like rock fell because of melting.

In the Paris 2015 climate change conference it was agreed that the global temperature will rise by 1.5 degrees by the end of the century, but the emissions emitted in the last one decade was so high that the global temperature will rise by 1.5 degree by 2030, which is 70 years before the prediction that was made in 2015.

This is too hot for the Himalayas, because the mountains are heating much faster resulting in the water, which was frozen, rough and hard melting and falling apart.

IMAGE: Vehicles and other structures devastated by mud-laden floodwaters in Nuwakot, Nepal. Photograph: ANI Video Grab

So you saw floods in Kedarnath in 2013 in which 6,000 people died, and again in 2021 in Chamoli, Uttarakhand.

The same thing that happened in Uttarakhand in 2021 happened in 2026 in Nepal.

Sikkim too faced the same thing in 2023.

Such incidents were very rare earlier but now these things are very frequent.

There needs to be a monitoring of glaciers in high altitude areas and one needs to check regularly how geological changes are taking place.

We can mitigate that by regular monitoring but unfortunately, hardly any monitoring is happening.

And without monitoring those higher altitudes of Himalayas, people are suffering.

Moreover, the Hindu Kush Himalaya region is located in eight countries so border cooperation is also needed.

Political borders don’t stop such mishaps.

So, what happens in the Kosi river of Nepal impacts Bihar in India and similarly what happens in Tibet impacts Nepal.

There are 10 major rivers in the Hindu Kush Himalaya region which flow in eight different countries, and a flood disaster in one country can lead to devastating consequences in the neighbouring country too.

‘Due To Global Warming, Glaciers Are Getting Heated Up And Loosening’

Nepal experienced sudden floods in the Bhote Koshi river in July 2025, when authorities concluded that a glacial lake outburst had caused flooding near the Nepal-China border. Does that event tell us anything about the risks in this region today?

It is quite frequent and this is happening in many places, but monitoring is not happening.

We don’t have much information to really forecast what happened.

These rivers have swept away many towns as our town planning too needs to be proper for future use.

The Nepal flood is a warning as to how much we are ready to curtail our emissions.

The Paris Declaration in 2015 had a clear agenda to reduce emissions but that is not being followed up.

For someone who isn’t familiar with the term, what exactly is an ice avalanche? How does it form, and what causes a large mass of ice or rock to suddenly collapse?

Density of any mass really helps to keep it intact.

Now due to global warming, high altitude glaciers are getting heated up and loosening.

And anything that is loose will fall down, resulting in an avalanche followed by floods which has a cascading effect.

Looking at the wider Himalayan region, what concerns you most about the increasing number of glacier-related disasters — and what can Nepal, India and other Himalayan countries do to reduce the risks?

There were 350 scientists who came together in 2019 and presented the Hindu Kush Himalaya assessment report for the first time.

There was no baseline data then.

Now we have baseline data and we at least know what is happening so that calls for the eight countries in this region to take an action call.

This kind of floods will be more aggravated in future because the climate is changing and temperature is rising.

For that, all these eight countries will have to come together.

If a river is originating in China and coming to India, then both countries will have to work together; similarly, if a river is originating in Sikkim in India and flowing into Bangladesh, both countries will have to work together.

In upper catchment areas where you have glacier mass or glacial lake, it has to be monitored river basin-wise.

And if there is a danger, it needs to be mitigated.

If it is a glacial lake outburst kind of situation you got to protect the moraine. Protecting the moraine from a glacial lake means stabilising or reinforcing the natural wall of rock, rubble, and debris left behind by a melting glacier so it does not break and cause a catastrophic flash flood.

Here in the Nepal flood case, the glacier mass came down from the Nepal side and it hit the river which is on the border between Nepal and Tibet.

When it came down on the Nepal side the water blew away the checkpost on the Tibet side.

Therefore, we need all the eight countries to come together and monitor glacial lakes, permafrost, glacier melting and work with policymakers.

Bhutan has shown us the way in the past by doing very good monitoring.

Bhutan shared its pioneering glacial lake mitigation techniques and frameworks through regional information-sharing, especially for Nepal.

But then there are 8,000 glacial lakes in the Hindu Kush Himalayan region and they are monitoring only a few of them.

Could this tragedy be prevented or forewarned? What warning signs should scientists normally look for before an ice avalanche or sudden glacial flood?

To begin with, the scientists can with risk mapping point out potential high vulnerable zones.

If they are able to map in six months to one year which are the rivers and which are the settlements, that is the first thing needs to be done.

Secondly, wherever there is high risk, good monitoring has to be put up so risk warnings can be given from time to time.