A new and first-of-its-kind study from an international team of scientists led by UK’s Newcastle University has found that nearly 15 million people around the globe are at risk from deadly flooding caused by glacial lakes, with around half of those exposed concentrated in just four countries: India, China, Peru, and Pakistan.
The phenomenon of glacial lake flooding is formally known as a “glacial lake outburst flood”, or GLOF. As temperatures around the planet continue to rise due to climate change, glaciers are melting at a rapid pace into glacial lakes. If a lake rises too high or the surrounding land and ice give away, the lake could “burst”, sending water and debris rushing down mountains. Living downstream from a glacial lake is incredibly dangerous for this reason.
Tom Robinson, co-author of the study and a disaster risk researcher at the University of Canterbury in New Zealand, described glacial outburst floods as “inland tsunamis” with an impact comparable to a dam collapse.
“These glacial dams are no different to constructed dams,” Robinson said. “If you take the Hoover Dam, for instance, you’ve got a massive lake behind it, but if you suddenly remove the Hoover Dam, that water has to go somewhere, and it’s going to come cascading down a valley in massive flood waves.”
The study, which involved scientists from several countries, was the first study to examine the effects of glacial lake outbursts. The research team looked at 1,089 glacial lake basins worldwide and the number of people living within 30 miles of them, evaluating the level of development in those areas and other indicators as markers of vulnerability to GLOFs. They then used this information to “quantify and rank the potential for damage from GLOFs” at a global scale and assess communities’ ability to respond effectively to a flood.
“We had glacier lake outburst floods in the past that have killed many many thousands of people in a single catastrophic flooding event,” said Robinson. “And with climate change glaciers are melting so these lakes are getting bigger, potentially getting more unstable.”
Lead researcher, Caroline Taylor, a doctoral student at Newcastle University, said: “This work highlights that it’s not the areas with the largest number or most rapidly growing lakes that are most dangerous. Instead, it is the number of people, their proximity to a glacial lake and importantly, their ability to cope with a flood that determines the potential danger from a GLOF event.”
Previous outbursts have killed thousands and damaged millions in critical infrastructure; the Cordillera Blanca in Peru is one such hotspot. Since 1941, the area has seen more than 30 glacial disasters, including glacial lake outbursts, that have claimed over 15,000 lives. Similarly, Pakistan, home to more glaciers than anywhere else in the world, saw at least 16 glacial lake outbursts in 2022 alone.
As global temperatures continue to rise to record-breaking heights, Robinson hopes the team’s research can help leaders from around the world determine which countries and regions are most in need of early warning systems for extreme glacial flooding.
“We, as a global community, only have limited resources — and some of us have access to more resources than others,” said Robinson. “We want to be making sure those resources are put to good use in the areas where impacts could potentially be quite severe.”