Climate change increasing risk of floods caused by lakes

By Gwyn Wright via SWNS

People are at greater risk of floods caused by lakes emptying due to climate change, warns a new study.

Researchers raised the alarm after images showed how a large lake in Patagonia suddenly emptied two years ago.

The sudden drying up of Greve Lake (Lago Greve), in the icy far south of Chile, was the biggest such event ever recorded on a satellite.

Scientists in Japan say it lost a colossal 18 meters or 3.7 giga-tonnes of water between April and July 2020.

The academics were studying glacier fluctuations in Chilean Patagonia using satellite images when they noticed that the lake had shrunk significantly.

The team says it dried up because a sediment bump in one arm of the lake collapsed.

It is a proglacial lake, a type that forms when melted water from retreating glaciers is trapped by ice or debris.

Global warming has led to an increase in the number and volume of this type of lake, which in turn causes glaciers to melt even faster.

These lakes can drain very quickly when the dams which contain them fail.

Such catastrophic events cause floods which put the safety of people and ecosystems downstream at risk.

Researchers argue experts should monitor these proglacial lakes and study how they interact with their surroundings, but that this can be hard because they are often remote.

This huge loss of water even changed the gravity field of Earth, as recorded by satellites.

Researcher Dr. Shin Sugiyama from Hokkaido University said: “These results provide detailed information on large-scale glacial lake outburst floods, which occur very rarely, and are important for understanding disasters caused by glacial lake failures.

“The study provides concrete data that can be used to better understand the dynamics of the interactions between glaciers and the lakes they form.

“The observed changes in the water level of glacial lakes can be used to predict changes in the glacier inflow into the lakes."

The findings were published in the journal Communications Earth and Environment.