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The Roof of the World is Melting

Climate change is speeding the melting of glaciers; the implications for Asia are widespread

By Asian Development Bank

As the world’s highest mountain above sea level, Mount Everest is renowned globally—its glorious peak a symbol of the pinnacle of success humankind can achieve.

A full view of the Khumbu Icefall, en route to the Everest basecamp as seen from Thukla.

But in August 2024, it was in the news for a devastating reason: a glacial lake in Everest’s foothills burst, flooding the small village of Thame, home to some of Nepal’s famed Sherpas.

While thankfully no casualties were reported, the glacial lake outburst flood (GLOF) displaced dozens of people, destroying many homes, a school, and a hydropower plant which provides electricity to several villages in the Everest region.

“The recent floods have devastated our beautiful valley of Thame, leaving significant damage to homes and infrastructure,” said Kami Temba Sherpa, a doctor at the village’s damaged clinic. “Once a green valley, it is now covered in debris.”

“We have established a temporary clinic, but challenging road conditions have severely impacted service delivery,” he said. “Access to health services is critical for the community, and recovery efforts are ongoing.”

The village was one of the Everest region’s tourist hotspots, with almost all residents entirely reliant on the sector. At the moment, without a detailed geological investigation and understanding of risks, government authorities and the villagers are unsure if the village should be rebuilt in the same location or resettled elsewhere.

As global warming accelerates glacial melt across Asia, such GLOFs are becoming riskier and more likely – especially as they interact with other hazards.

With around 2 billion people across the continent relying on meltwater from glaciers and snow, accelerated glacial melt has dire implications for the region’s water security.

WATER TOWERS

Mountain glaciers act as natural freshwater towers, storing ice and snow that melts, gradually, throughout the year.

That meltwater trickles down into rivers and streams which provide water for drinking and generates hydroelectric power.

And given their role in providing water for irrigation, livestock, and fishing, glaciers are essential building-blocks of agriculture and food security.

Wetlands in the high mountains and glacial lakes – which pool into the gaps created by glacial erosion of the land around them – are unique ecosystems. They serve as habitats for various animal and plant species that can mostly only be found in these alpine or cold mountain environments.

Permafrost—ground that has been frozen continuously for at least two years—stores carbon, supports biodiversity, and helps to stabilize slopes. As glaciers lose mass, the essential services provided by these icy behemoths are increasingly under threat.

ASIA’S GLACIERS

One of the world’s most important water towers is the Hindu Kush Himalayas (HKH), also called the Earth’s Third Pole because of its massive ice reserves.

The 3500-kilometer mountain range stretches across eight countries: Afghanistan, Bangladesh, Bhutan, People's Republic of China, India, Nepal, Myanmar, and Pakistan.

The HKH also feed 10 major river basins: Amu Darya, Brahmaputra (Yarlungtsanpo), Ganges, Indus, Irrawaddy, Mekong (Lancang), Salween (Nu), Tarim (Dayan), Yangtze (Jinsha), and Yellow (Huanghe).

The HKH, however, is warming three times faster than the global average. A study by the International Centre for Integrated Mountain Development (ICIMOD) showed that glacial melt in the region was 65% faster from 2011 to 2020 than in the decade before.

Other river basins in South, Central, and West Asia also rely on glacial melt from other mountain ranges such as the majestic Pamirs, Tien Shan, and the Greater Caucasus.

The 77-kilometer long Vanjakh (former Fedchenko) glacier in the Pamirs is the longest glacier outside the polar regions.

Centered in Tajikistan, the Pamir mountains – about 10% of which are glaciated – adjoin the HKH. Pamir glaciers also feed the Amu Darya River, a critical 2,400 kilometer-long water source for Afghanistan, the Kyrgyz Republic, Tajikistan, Turkmenistan, and Uzbekistan—particularly for agriculture.

In the Greater Caucasus, home to more than 2,000 glaciers providing freshwater and hydroelectric power to people in Azerbaijan and Georgia, glacier loss is accelerating. Studies suggest that from 2000 to 2019, glaciers in the Greater Caucasus lost an estimated 11 billion tons of water at a melt rate four times faster than from 1911 to 1960.

How Glacial Melt Affects Water Across Asia

The accelerated melting of glaciers and snow affects the hydrological cycle. A less predictable water cycle means that ecosystems and people living in river basins are faced with either too much or too little water at various points in time.

TOO MUCH WATER IN THE SHORT TERM

Higher water runoff from accelerated glacial melt is making river basins more vulnerable to hazard risks such as GLOFs, floods, and landslides. With thousands of glacial lakes forming or expanding, Asia is more vulnerable than any other region to GLOFs.

The impacts can be magnified depending on where they materialize. In South and Southeast Asia, for example, monsoons bringing heavy rains supercharged by climate change can make flooding worse. In the mountains, earthquakes and thawing permafrost can destabilize the ground and – with excess water – cause landslides and mudslides.

In rapidly developing regions such as the HKH, understanding how these hazards compound is paramount for infrastructure development and to avoid disasters – too many of which Asia has seen in recent years.

In 2021, debris floods hit Melamchi in Nepal, damaging key infrastructure and devastating communities. The disaster was the result of cascading events stretching back years. A 2015 earthquake destabilized the slopes, later followed by accelerated glacial melt, heavy rainfall, a flood-induced GLOF, and landslides.

In 2022, accelerated glacial melt and heavy rains in Pakistan caused massive riverine and urban flooding that also triggered landslides. A third of the country was submerged, damaging millions of homes and large swaths of critical infrastructure, affecting some 33 million people.

Governments in developing Asia need a deeper understanding of multi-hazard risks to set up appropriate early warning systems, mobilize funding during emergencies, and build climate- resilient infrastructure.

ADB is helping its developing member countries build climate- resilient infrastructure by strengthening their ability to assess complex cascading risks – such as GLOFs and earthquakes – and develop innovative financing options.

These include mobilizing concessional finance and using insurance and insurance-like services to transfer risk and ensure that the costs of building infrastructure resilient to these rising risks are not too high. Marrying regulation with bespoke financial products is essential to attracting the private sector.

“With climate change causing more extreme weather conditions and melting glaciers at an unprecedented rate, we need different approaches to building and financing climate-resilient infrastructure,” said ADB Principal Economist Declan Magee. “Investments should be based on high quality and dynamic assessments of multi-hazard risks that integrate climate modeling so we better understand and prepare against potential impacts.”

TOO LITTLE WATER

Glaciers normally provide a steady stream of water at drier times of the year. But as they shrink, there will be less meltwater. The impact is worse when combined with heatwaves, droughts, and changes in precipitation patterns – all of which are already happening.

In many glacier-fed rivers, with less surface water available for irrigation, people are forced to tap more groundwater. Many areas, particularly those in the HKH region, are already experiencing water shortages from over-extracting groundwater. In the future, the combination of dwindling snowmelt water and depleted groundwater will have severe impacts for irrigating crops for food production. Given the HKH region produces about a third of the world’s rice and a quarter of its wheat, this could eventually threaten local economies and global food security.

In arid and semi-arid parts of Central and West Asia, communities already face water challenges.

In Azerbaijan, host of COP29, villagers near some of the country’s highest mountains—Bazurduzu, Tufandag, and Shahdag—have noticed decreased glacial ice and snowfall in the past 30 years.

This is already making life difficult for communities who rely on glacial and snowmelt for drinking water and agriculture.

“Some springs have dried up and the water in the rivers has decreased,” said Badalov Hajibala, a 68-year-old resident of Khinalig village who previously worked as a glacier researcher.

“Our income is at the expense of nature. If there is water scarcity in nature, erosion occurs in the soil and plants die. This affects us negatively and it becomes difficult to live here,” he said. “Because there is water scarcity, there will not be enough water for drinking, for cattle, and for growing plants. This would mean a great disaster for us.”

Sonakhanim Shingayeva, who lives in Laza village, said water in springs and rivers now seems to be around half of what it used to be.

“It does not snow as much as in previous years, so there are less glaciers in the mountains,” she said. “If it continues like this, we will have a serious lack of water in the future. And there is no life without water.”

Understanding these changing precipitation patterns is vital to governments and development agencies operating in Central and West Asia. That’s why ADB is financing a series of rigorous climate risk assessments that will provide an up-to-date scientific understanding of how the climate is changing in this part of the world – and likely to impact people like Badalov and Sonakhanim.

The studies will form the bedrock of a major regional program being developed by ADB to help promote transboundary cooperation on water, arrest declining agricultural productivity, and stymie social vulnerabilities emerging due to climate change – particularly for vulnerable mountain communities.

“Climate adaptive planning, investments in watershed protection and climate resilient irrigation systems – these are all essential to ensuring long term food security given the climate crisis,” said ADB Climate Change Specialist Kathleen Coballes. “Since these impacts transcend national borders, it’s essential for these countries to work together to protect their critical, shared water resources.”

One way countries are already working together is through the Central Asia Regional Economic Cooperation (CAREC) Program, an ADB-supported platform. The bank is facilitating cross-sector dialogue among officials—particularly in the Aral Sea Basin which is connected to the Amu Darya.

RESILIENT RIVER BASINS

Apart from impacts on agriculture, dwindling river flow will also curtail water supply and sanitation systems—a major problem in the HKH region where more than a billion people already lack access to basic sanitation.

Communities or even industries may need to migrate in search of freshwater and new livelihoods.

ADB offers a comprehensive set of solutions to build resilience in river basins. These include long-term, multi-project approaches designed to achieve large-scale impact. This can also help to bring about the conditions to ensure that prospective private sector lenders are willing to finance the projects, because there is not enough public sector funding to meet Asia’s needs.

Programs include strengthening governance through policies and legislation; building the capacity of hydrometeorological systems to gather, store, and analyze data; and increasing public investments in water security.

For example, in Bhutan—which relies on hydropower for domestic use and exports—ADB helped develop a national integrated water resource management plan. This has improved the government’s capacity to manage one of the country’s most important assets. ADB also helped lay the groundwork for irrigation investments that will help raise agricultural productivity.

“ADB has worked with many countries over the years to put the right policies and plans in place to improve integrated management of their water resources and enable more investments in climate resilient infrastructure that will better prepare them against climate impacts, including accelerated glacial melt,” said ADB Principal Water Resources Specialist Lance Gore. “We are also developing solutions tailored to specific needs in upper, middle, and lower basins for sustainable water and land use, ecosystem management, and disaster risk reduction.”

Mobilizing enough adaptation finance to build resilience in glacial melt-affected countries is crucial.

As world leaders gather in Azerbaijan for COP29, it is also essential to step up efforts to cut greenhouse gases that are causing climate change in the first place.

If current nationally determined contributions are achieved, the world would be headed for a 2.2°C temperature rise – which would mean glaciers in the HKH would lose about half their ice by the end of the century.

If global temperatures rise by 3°C to 3.5°C —up to 80% of HKH glacial ice could be lost, with the glaciers unlikely to survive in the long run.

Under this catastrophic scenario, the HKH’s river basins would hit peak water around 2050. This means there would be increasing water runoff from glaciers prior to 2050—causing more hazard risks—and declining water runoff after 2050 which will lead to drought and water shortages.

Meeting the Paris Agreement goal of 1.5°C is essential to prevent massive glacial loss and protect ecosystems and future generations.

Happy students waving hands. Mogh, Chitral, Khyber Pakhtunkhwa, Pakistan.

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