In the mountains of Peru, melting glaciers have swollen the lakes that catch their meltwater, putting tens of thousands of people in major cities below in the path of.
Now a new study using NASA satellite data shows it's a problem facing people in mountainous regions around the world.
"This is an issue for many parts of the world where people live downstream from these hazardous lakes, mostly in the Andes and in places like Bhutan and Nepal, where these floods can be devastating," lead author Dan Shugar of the University of Calgary said in a NASA release Monday.
In 2019, I traced the path of one such devastating flood and another near-miss in Peru. Numerous lakes in the Andes sit below towering ice caps undergoing a phase change as climate change converts them to water gathering in the swollen basins. Vulnerable communities sit below these lakes, but little data exists on just how overfilled and dangerous many glacial lakes have become.
"We have known that not all meltwater is making it into the oceans immediately," said Shugar. "But until now there were no data to estimate how much was being stored in lakes or groundwater."
The study, the largest ever survey of glacial lakes, finds their overall volume is up by about 50 percent over the last three decades. It was published in the journal Nature Climate Change on Monday.
Glaciers receding due in large part to climate change not only bloats glacial lakes, it also threatens communities downstream. The destabilization of melting ice, rocks and soil can trigger more avalanches, landslides and floods.
"Fortunately, organizations like the United Nations are facilitating a lot of monitoring and some mitigation work where they're lowering the lakes to try and decrease the risks," Shugar added.
However, there are challenges to this monitoring and mitigation work,, where governments have been slow to respond and often meet with local resistance. And the problem is likely to accelerate as the world continues to warm.