Melting glaciers are threatening 15 million people with devastating floods. And four countries face the greatest threat, a new study indicates. The research, led by Newcastle University, England, is the first global effort to map potential hotspots for these floods.
As the climate warms, glaciers retreat and meltwater accumulates in depressions created by the glaciers, forming lakes. These lakes can burst their banks suddenly and cause flash floods, a rapid flow that can spread more than 120 km from the original site.
This is a phenomenon called flooding by Violent overflow from the glacial lake, O GLOF, In its abbreviated form in English. These events can be very devastating, causing significant loss of life and damage to property, infrastructure and agricultural land.
Since the 1990s, there has been a rapid increase in the number of glacial lakes as a result of climate change. And at the same time the number of people living in these valleys has also increased considerably.
The study, published in the journal Nature Communications, assessed the condition of the lakes and the number of people living beneath them. and shows The first global analysis of GLOF risk areas.
“The effects of these floods affected a huge number of people around the world,” said Rachel Carr, a glaciologist at the University of Newcastle and lead author of the study.
“It can happen at any time, which makes it especially dangerous, because it’s hard to predict when it will happen.” Researchers found that 15 million people live within 50 km of a glacial lake.
People who face the highest risk of GLOF live in mountainous countries in Asia and South America. people living in India, Pakistan, China and Peru They add up to more than half the people who are at risk.
Nearly one million people in Asia live just 10 km from a glacial lake, the study said. researchers emphasize that There is an urgent need to investigate more into the threat of a GLOF in the Andes due to the high number of people living near a glacial lake in Peru and their reduced ability to deal with the impact of any one of these events.
“What’s important is how close people are to those lakes and their ability to respond to a disaster,” says Dr Carr. “A lot of inventory studies have been done [de los lagos]… But our study has changed that. What’s downstream matters just as much, if not more. I think it’s going to take a major rethinking of the way we think about the problem.”
Lakes formed by melting glaciers have natural dams of loose rock and ice They can fall suddenly and unexpectedly. The ensuing floods are dense and rapid, and in many cases powerful enough to destroy critical infrastructure. Dam breaks are complex, but often occur when a chunk of rock or ice from surrounding mountains collapses into the lake.
This causes a wave to sweep across the lake like a tsunami, destabilizing it when it reaches the dam. Other factors include the gradual build-up of meltwater, increasing pressure against the dam, and melting of any ice cores holding it together.
Rather than trying to predict which dams were most likely to fail, the researchers looked at which lakes would pose the greatest danger if they breached their banks. The study also highlights the importance early warning system, Like fast cameras.
Stephen Harrison of the University of Exeter, a leading expert on the effects of climate change on glacial lakes, who was not involved in the research, told the BBC: “This is important research.” “It alerts politicians to the potential impact of future climate change.”
Dr Harrison says the research is only a first step Better understanding of the impact of climate change on GLOF. This relationship is complex and hard to prove, so scientists suspect it’s a long stretch between cause and effect.
Research suggests that the increase in flooding that began in the early 20th century and peaked in the 1970s may have been a late response to past climate changes.
While scientists expect glacial flooding to increase as a result of human-induced climate change, so far no such increase has occurred.
