Introduction

They have been described as the water towers of the world, and with good reason. Glaciers are a vital source of fresh water for more than half of the global population, but as they shift and recede, they are altering the lives and the livelihoods of the communities that rely on them.

Long-term water availability is just one of the challenges facing humanity as it tries to get to grips with these physical changes to glaciers. There are also implications for water-based ecosystems and for the agricultural and hydropower sectors.

More alarmingly, as global temperatures increase and our glaciers recede, the resulting instability can be disastrous, something witnessed recently when a huge landslide destroyed 90% of the village of Blatten in Switzerland.

Glacial Lake Outburst Flood events (GLOFs) are another deadly hazard. These catastrophic events occur when large volumes of water are suddenly released from unstable glacial lakes, often dammed by ice or moraines (masses of rocks and sediment).

Himalayan regions such as Nepal, Tibet and Uttarakhand have witnessed increasingly devastating GLOF events in recent decades, causing widespread destruction to lives, livelihoods, and infrastructure downstream. In Nepal alone, there are upwards of 2,000 recorded glacial lakes, with 21 identified as potentially dangerous by the International Centre for Integrated Mountain Development (ICIMOD).

As well as their physical presence, glaciers are also known to hold cultural and spiritual significance, particularly for Indigenous Peoples, some of whom believe them to be sacred spaces and the abode of deities.

Small wonder then that 2025 was designated by the United Nations as the International Year of Glaciers' Preservation to highlight their importance and ensure that those relying on them and those affected by their changes receive the necessary advice and support.

Much of that advice, whether it be trying to discover why our glaciers are melting or observing and measuring those changes to improve disaster preparedness, comes from the scientific community.

Academics at the University of Leeds are at the forefront of that research, working alongside affected communities to find out why our glaciers are under threat, what can be done to mitigate that threat, and to forewarn them when disaster could be imminent. 

With local air temperatures dipping as low as −20°C on parts of Mount Everest, we might be forgiven for thinking that the snow up there was nowhere close to melting point.

But when a research team led by Professor Duncan Quincey from the School of Geography trekked to Base Camp in 2017 to drill into the iconic Khumbu Glacier, they were surprised to learn that the ice temperatures inside were only −3.3°C, with even the coldest ice being a full 2°C warmer than the mean annual air temperature.

These worrying results showed that high-elevation Himalayan glaciers are vulnerable to even minor atmospheric warming and would be especially sensitive to future climate change.

Glaciers in the highest mountains of the planet are an extremely important source of water with hundreds of millions of people, including many in India, Pakistan and Bangladesh, depending on runoff that originates in the high Himalaya.

Changes in the rate of glacier thaw threaten the water supply on which so many depend. Another emerging danger is an increase in flooding from failures of natural ice or sediment dams, producing so-called Glacial Lake Outburst Floods.

The research team wanted to understand why the ice temperatures inside the world’s highest glacier were so warm, and what this might mean for future rates of ice recession.

Fast forward to spring 2025, and Professor Duncan Quincey and a team of researchers from the University of Leeds and Aberystwyth University were making preparations for a return trip. This time they were to go even higher – half a kilometre above Everest Base Camp, where they would drill into the glacier and use the boreholes to record ice temperatures.

They would have to negotiate the infamous Khumbu Icefall, regarded as one of the most demanding sections of the South Col route to Everest's summit, while their equipment was transported by helicopter.

“Although we have worked at and around base camp on half a dozen occasions previously, this is the first time we have continued up-glacier and above the icefall. This means we're exploring new ground, and only a handful of scientists have walked this path before us. If we manage to capture any data, then they will genuinely be the first of their kind,” said Professor Quincey.

“This trip will be the most physically and logistically demanding expedition I've ever been part of, and the unknowns are plentiful - we're worried about whether our equipment will work at such high elevations, and if it does work, whether we will be able to collect and export our data effectively.”

Despite these challenges, the team was able to drill down into the glacier to a depth of 12 metres and extract ice cores, allowing them to examine what is happening in the sub-surface layers. A weather station was also installed to allow the team to monitor conditions over the coming months.

There is still much work to be done to analyse the data, but the researchers’ working hypothesis is that intense radiation from the sun is melting the snow even when air temperatures are below freezing.

As the meltwater refreezes, it can warm the snow by several degrees, creating glacier ice that is much closer to the melting point than has previously been realised.

“But we do need to address the question of how widespread this issue is, so to get to some more of those high-altitude sites would be fantastic.”

Hear more about Professor Quincey’s expedition and the work that the University is doing to help protect communities at risk in the latest episode of our 'How To Fix...' research podcast which asks, “How can we minimise the impact of melting glaciers?”

For more information on any of the research featured, email the University of Leeds Press Office at pressoffice@leeds.ac.uk.