Glacial lakes at risk of bursting, flooding
More than 12,000 deaths have already been attributed to glacial lake globally
Paris, May 2: An increasing number of people are being threatened by flooding caused by glacial lakes bursting, scientists have warned. More than 12,000 deaths have already been attributed to glacial lake outburst floods worldwide.
As the planet warms and glaciers recede, meltwater accumulates and forms lakes, often as a result of ice or moraine acting as a dam. Since 1990, the volume, area and number of these glacial lakes has increased by 50% globally.
When these lakes become too full there is a risk that they may breach or overflow, releasing huge volumes of water and causing catastrophic flooding.
Some lakes are more dangerous than others, and more likely to result in what are known as glacial lake outburst floods (GLOFs). Stephan Harrison, a professor of climate and environmental change at Exeter University, said: “The ones we’re concerned about are the very steep mountain valleys in the Andes and in the Himalayas, where you have glaciers retreating up into their steep valleys with lots of opportunity for bits of mountainside to fall off into lakes.”
The correlation between rising temperatures and glacial lake outburst floods is complicated. While glacial lake formation and growth can be attributed to anthropogenic climate change, the triggers that can cause disastrous flooding are often down to nonclimatic factors such as moraine dam geometry, earthquakes, ice or rock avalanches into the lake or extreme rainfall.
Adam Emmer, a geographer at the University of Graz in Austria, said: “You need two conditions to generate a disaster – high magnitude GLOF, and exposed population as well as assets in its path. Population expansion along the potential GLOF paths and lack of building development regulations may be even more important driver of GLOF risk. — Agencies