India, Pakistan among most exposed to flooding by glacial lakes

Some fifteen million people worldwide could be threatened by sudden overflows of glacial lakes, and the most exposed are the populations of the high mountains of Asia (India, Pakistan and China) and the Andes (Peru and Bolivia).

Flooding by glacial lakes

More than half of those fifteen million people exposed to this potential risk are concentrated in four countries: India, Pakistan, Peru and China, indicates a study published today by Nature Communications.

As the climate warms, glaciers recede and meltwater accumulates at their front end forming a lake, which can suddenly burst and create a fast-flowing Glacier Lake Overflow Flood (GLOF), which can spread even more than 120 kilometres in some cases.

These floods often occur without warning when a natural dam containing a glacial lake fails. The GLOF can cause material damage, to infrastructure and has already caused numerous fatalities, according to the magazine.

A team led by the University of Newcastle (UK) has produced the first global assessment of areas most at risk from glacial lake flooding and has identified priority areas for mitigation.

To do this, they studied 1,089 glacial lake basins around the world and the number of people living within 50 kilometres, as well as the level of development of those areas and other social indicators as markers of vulnerability to GLOFs.

They used that information to quantify and rank the damage potential of GLOFs on a global scale in 2020 and assess the ability of communities to respond effectively to a flood.

15 million people live near glacial lake

The results highlighted that 15 million people live within 50 kilometres of a glacial lake and that high-altitude Asia (covering the Tibetan Plateau, from Kyrgyzstan to China) is most at risk from GLOF, with 9.3 million. of people potentially at risk.

If the 1,089 glacial basins studied are ordered from highest to lowest risk, the first three are in Pakistan (Khyber Pakhtunkhwa basin); Peru (Santa Basin) and Bolivia (Beni Basin), encompassing, respectively, 1.2 million, 0.9 million, and 0.1 million people who could be exposed to GLOF impacts, the authors write.

The Andes are, according to the team, a region of "concern" with a potential GLOF impact similar to that of the high mountains of Asia, but with few published research studies.

This region should be the subject of more detailed studies to better understand this potential threat, due to the high number of people living near glacial lakes and their reduced ability to cope with the impact of such a flood, according to Newcastle University.

Risk from glacial flooding

Lead researcher Caroline Taylor, from the University of Newcastle, stressed that the present research shows that it is not the areas with the largest number of lakes or with the fastest growth that is the most dangerous.

The potential danger of a GLOF event is determined by the number of people, their proximity to a glacial lake and their ability to cope with a flood, he listed, in a university statement.

“Understanding which areas are most at risk from glacial flooding will enable more targeted and effective risk management measures to be taken which, in turn, will help minimize loss of life and damage to downstream infrastructure as a result of this major natural hazard ”, according to Rachel Carr of Newcastle University.

As glaciers continue to recede due to climate change, glacial lakes will expand and new ones will form, altering the spatial pattern of GLOF hazard.

Therefore, for the authors, further research is necessary to assess temporal changes in lake conditions, exposure and vulnerability, in order to determine the relative role of each in GLOF risk.

Melting glaciers signs of climate crisis

The melting of glaciers is one of the clearest and most visible signs of the climate crisis. A recent study, of which Rounce was the lead author, found that up to half of the planet's glaciers could be lost by the end of the century, even if the world's ambitious global climate goals, including the phasing out of fossil fuels, are met.

As temperatures continue to rise, Tom Robinson, a co-author of the study and a senior lecturer at the University of Canterbury in New Zealand said he hopes his research can help world leaders determine which countries most need early warning systems for extreme flooding from melting glaciers.

“We as a global community only have limited resources, and some of us have access to more resources than others,” he said. “We want to make sure that those resources are put to good use in the areas where the impacts could be quite severe.”

Robinson added that once there is investment in the most vulnerable countries like India, Pakistan, Peru and China, "we can move up that list and keep working," to save even more lives from these bursting glacial lakes.

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