New Delhi: Around three million people in India and two million people in Pakistan are at risk of sudden and deadly flooding from glacial lakes, a new study has found. Glacial lakes are a result of shrinking glaciers, which cause flooding in downstream areas. This is known as glacial lake outburst floods (GLOF).
The study titled ‘Glacial lake outburst floods threaten millions globally‘ was published by Nature journal. “India and Pakistan make up one-third of the total number of people globally exposed to GLOFs – around three million people in India and around two million people in Pakistan,” Indian Express quoted Tom Robinson, one of the authors of the study.
Globally, the study finds that around 15 million people are at risk of GLOFs due to expanding and rising in numbers because of global warming. Almost half of the affected populations live in four countries: India, Pakistan, China, and Peru.
Although GLOFs are not new, as they have been occurring since the Ice Age, the risk and impact have gone up by several levels because of climate change, authors of the study note. The reason why they prove extremely lethal is because of their suddenness, for they arrive with little warning and leave behind a huge trail of destruction, of lives and property.
The Kedarnath floods of 2013 can help one understand what GLOFs can do. The flash floods that year, resulting from the Chorabari Tal glacial lake, killed thousands of people.
“As the climate continues to warm, glacier retreat will form larger and more numerous lakes. At the same time, lakes are likely to become more exposed to GLOF ‘triggers’, such as a large landslide or ice avalanche entering the lake, displacing water, and causing the natural dam that impounds the lake to fail,” Robinson told Indian Express.
He further goes on to say that lakes that weren’t of concern in the past could pose danger in the future due to climate change which is taking place at an unprecedented level.
In fact, a previous study from 2020 also underlined the same point, noting that the number and total area of glacial lakes worldwide have increased by about 50% since 1990, Washington Post reported.
For the latest study, researchers employed existing satellite-derived data on different locations and sizes of glacial lakes with a global population model and a series of population metrics to understand the regions and populations that face severe risk from GLOFs.
“We’ve made a conservative estimate that anyone living within 50 km of a glacial lake and one km of a river that originates from a glacial lake could be impacted, either directly or indirectly, if one or more of the lakes upstream failed,” Robinson added.
In order to understand the impact of such catastrophic events, researchers of the study also relied on the data on levels of human development and corruption in these zones to determine how vulnerable local communities may be when floods occur.
The study underlines that 15 million people live within the 50 km danger zone of glacial lakes. However, it is the populations in High Mountains Asia (HMA) – a region stretching from the Hindu Kush all the way to the eastern Himalayas – who are at greater risk given that on average they live closest to glacial lakes. In fact, nearly 1 million in the region live dangerously close within a 10-km radius of a glacial lake.
An important point that the study brings to the fore is that the glacial flood risks don’t only depend on the size and number of glacial lakes in a given region. What needs to be considered to get a full picture is the size of the population living in a said area and their proximity to the danger zone as well as existing levels of social vulnerabilities.
This can be better understood from the examples of Greenland and Canada. Although they have a large number of glacial lakes in comparison, relatively fewer people are exposed to GLOFs due to population and low levels of corruption.
“While the number and size of glacial lakes in these areas (India and Pakistan) isn’t as large as in places like the Pacific Northwest or Tibet, it’s that extremely large population and the fact that they are highly vulnerable that means Pakistan and India have some of the highest GLOF danger globally. In fact, the most dangerous catchment in the world in our study is Khyber Pakhtunkhwa in Pakistan,” the IE report quoted Robinson.
For scientists, Peru was a surprise entrant to the top list and stands at the third position in terms of risk associated with GLOFs. Researchers conclude that glacial lakes across the Andes have gone up by 93% in relation to 37% in high-mountain Asia in the last two decades. Besides, most of the research and previous studies on the issue made the Himalayas their focus and gave little attention to the Andes, the authors of the latest study concluded.
According to Robinson, there is no single solution to minimise the risk of GLOFs but suggests that a multi-pronged approach could work. “Limiting climate change and keeping warming under 1.5 degree Celsius is a big one as this will help slow the growth of glacial lakes, but unfortunately a certain amount of ice loss is already ‘locked in’ – if we stopped all emissions today GLOF hazard will continue to increase for several decades,” he added, according to the IE report.