Skip to main content




‘A tsunami in the sky’: Climate change is melting Bhutan’s glaciers and the danger is real

‘A tsunami in the sky’: Climate change is melting Bhutan’s glaciers and the danger is real

Bhutan's glacial lakes are ethereal, but many are dangerous. (Photo: NCHM)

THIMPHU: High up in the mountains of Bhutan’s north, ancient glaciers punctuate a stunning, ethereal landscape. This landscape is a special one, enwrapped in myth and mystery. 

It is pristine land, largely untouched by humanity. Culture-driven conservation has endured here. 

The region’s tallest peaks have never been scaled by man, nor have its picturesque lakes been disturbed. It is out of respect - locals believe the mountains, lakes and glaciers are deities, to be honoured and feared.

Yet it is the impacts of manmade global emissions that is slowly destroying them nonetheless. Rising temperatures as a result of climate change is accelerating the rate of glacial melt in Bhutan’s highlands. In the silence of the mountain, now, danger looms - a killer that could unleash at any moment.

Glaciers are spiritually important for Bhutan, as well as being a critical resource. (Photo: NCHM)

For some glaciers, annual retreat levels are up to 35m, feeding massive amounts of water into surrounding lakes. The risk of these lakes collapsing - in a phenomenon known as a glacial lake outburst flood or GLOF - has the entire country on edge.

“With global warming, glaciers are melting and our water resources are moving faster downstream. We call it a tsunami in the sky, that can come anytime,” said Karma Drupchu, the national director of the country’s National Center for Hydrology & Meteorology (NCHM).

“Any kind of breach will result in a huge flood coming down the stream. It will have huge consequences because more than 70 per cent of Bhutan settlements are along the river valleys ... not only loss of life, but huge economic loss,” he said.

There are 17 glacial lakes in Bhutan considered potentially dangerous and at risk of bursting. (Photo: NCHM)

Analysis by NCHM has identified 2674 glacial lakes, of which 17 are categorised as potentially dangerous. Further accelerated melting of the country’s 700 individual glaciers means more lakes are being formed and the dangers for the country’s population and infrastructure is increasing.

READ: Commentary - Why I quit my day job and started cycling to Bhutan

Bhutan is the only carbon negative country in the world and it takes its role in preventing global climate change seriously. The country’s constitution mandates the protection of the environment and economically lucrative but environmentally damaging industries have been rejected in favour of conservation.

But the brunt of climate change has arrived regardless of this small nation’s resistance. For Prime Minister Lotay Tshering, the impact on glaciers is both a physical and spiritual burden for Bhutan to carry.

Warm summers and a lack of snow in winters is resulting in greater glacial declines. (Photo: Jack Board)

“It concerns us a lot because from a spiritual point of view, it’s not just a pool of water. Spiritually, we believe that there is life in it, we respect that and environmentally it is a fact that we are losing our glaciers to global warming,” he told CNA in an exclusive interview.

“We’re under constant threat and that is the most unfair part.”

He added: “Glaciers that are lost, are lost forever. How many lives, not just human beings, but other lives are dependent on that? Not just the country and the economy but the whole lifecycle will be destroyed. but soon in coming generations there may not be any lakes to burst. That would be a real disaster”. 

About 70 per cent of Bhutan's settlements are along the river valleys. (Photo: Jack Board)

GLOFs have happened before in Bhutan and the impact remains in the memories of those who have experienced such a disaster. Small incidents are relatively common in the lakes region, but the last major event to crescendo towards populated areas was back in 1994.

“I was right here in the village, in my house. Suddenly an old relative who was living with us at the time, frantically screamed at me to look out of the window. I dashed to the window and looked below. What I saw terrified me, the 75-year-old recounted.

The village of Richena was hit by a damaging flood in 1994. (Photo: Jack Board)

“The river had swollen to a dark and muddy river and upon it sat hundreds of fresh uprooted trees and logs including large swathes of undergrowth. I was beyond petrified that it was going to destroy lives and properties and there was nothing I could do,” he said.

Twenty five years ago, there was no warning for villagers living along the river. The 1994 flood killed 21 people and caused extensive damage to agricultural land, destroyed houses and wiped out fish stocks in the river. 


Since then, scientists have more closely examined the lakes and the impacts of temperature on their stability. 

Now, a sophisticated early-warning system is installed throughout the lake and river system to give people the best chance to act before a flood hits.

The bridge at Punakha's iconic dzong would be at risk from a future GLOF. (Photo: Jack Board)

“They are worried. They know the glacial lake is going to burst at any time due to global warming,” said Tshewang Phuntsho, an officer from the Department of Disaster Management in Punakha.

“But at the same time, we are also prepared,” he added, explaining that simulation drills and awareness campaigns are building resilience among at-risk populations.

Glaciologists at NCHM have also been physically examining the dangerous lakes on an annual basis. Some require even more intense monitoring - like Thorthormi Lake in the Lunana region, which is considered the most volatile glacial lake in Bhutan. 

Locals say there are worried about the risks of GLOFs, but preparations are better than in the past. (Photo: Jack Board)

Two personnel are stationed permanently near its edge to visually monitor any changes or risks. The nearby community would have only an estimated 30 minutes to evacuate in the event of an outburst. 

“Some lakes are nearly impossible to reach there. But most of the potentially dangerous ones, we went there and did the ground checks”, said NCHM executive geologist, Phuntsho Tshering.

“As a glaciologist and a scientist, seeing them is quite scary. If something pushes down, the barriers cannot hold. We know something is happening up there, it’s not safe, it’s critical,” he said.

Bhutan wants to continue to tap the potential of its water resources, despite the risks. (Photo: Jack Board)

Despite recent efforts to lower the lake’s levels using a team of physical labourers with handpicks and other simple tools in the freezing waters, there are few viable options to mitigate the dangers.

Nearly all of the lakes are at high altitude where temperature increases are amplified compared to low-lying areas. 

Record temperatures were recorded in 2019 around Bhutan’s most dangerous glacial lakes, 4,500m above sea level. 

Warmer summers and winters without snow is contributing to the glacial decline and extreme rain events in the Himalayas is adding pressure to lake capacity. 

If Thorthormi was to burst, there are dire forecasts about the resulting damage to the small but fertile valleys downriver, which Bhutanese rely upon - 70 per cent of the country’s population depends on subsistence agriculture. 

Forested areas could be wiped out and significant religious buildings such as the Punakha dzong could face devastation.

National modelling suggests river flows could be severely compromised by 2050 due to climate change. (Photo: Jack Board)


Perhaps even more crucially is the risk to Bhutan’s hydropower sector, which the national economy has come to overwhelmingly rely upon as a major revenue driver via exports to neighbouring India. 

Clean energy is also one of the ways Bhutan is offsetting regional emissions. A powerful GLOF could wreak havoc on critical power-generating infrastructure. 

“Our biggest revenue is from hydropower as of today and the hydropower we have is very highly climate dependent. We have realised that and we are a little worried about that,” the prime minister said.

Two of the biggest and most crucial projects are being constructed on the same system, downriver from Thorthormi Lake - the 1200 megawatt Punatsangchu-I and 1020 megawatt Punatsangchu-II. 

Both are run-of-river, meaning that they rely on natural flow to generate electricity. With projections that the flow of rivers in Bhutan may be majorly compromised by 2050 due to shifting rain patterns, this approach may need to change.

Hydropower is Bhutan's most important industry. (Photo: Jack Board)

READ: Southeast Asia’s hydropower boom grinds to a halt as COVID-19 stalls projects

READ: 'The colour is blue’ - Strange changes to Mekong River as hydropower dams and climate change make their mark

The most ambitious hydropower project in Bhutan’s history - more than twice as large as any other - will be different. 

The Sankosh dam will be built as a large-scale reservoir, environmentally more disruptive, but more resilient to climate change. It is a tough concession to make in a nation that has vigorous screening of all of its infrastructure projects through the Gross National Happiness Commission.

Despite a triple threat - from GLOFS, earthquakes and river reliability - the government is keen to press on. 

“Sankosh would be one mega hydropower project we’d like to start and then see how it does for the next decade or so. If the climate change becomes more dependable, if it settles down a bit, we can embark onto the next project. We have to be very careful with this,” said the prime minister.

“Water is the only possible resource that we have to generate because of conservation efforts,” said Drupchu of NCHM. 

“We could go for logging and become rich, but the conservation and protection of the environment is the top priority. If you don’t utilise the water, it will automatically flow down. The money is more or less flowing. So why don’t we tap it?”

Scientists describe the situation as "scary" at high-altitude lakes. (Photo: NCHM)

Whether these decisions prove to be prudent will depend on nature. Like a coastal community on alert for a future tsunami, life must go on. But there is trepidation.

Every time a Bhutanese scientist begins work at a glacial lake, there will be prayers and offerings to the deity believed to be contained within. It is both a cultural duty and a cautionary measure.

“We appeal to them that we are not doing this for fun,” said Tshering, the geologist. “This is for safeguarding the people.”

Delve deeper, read our special coverage on climate change here:

Source: CNA/jb(aw)


Also worth reading