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The volume of lakes formed as glaciers around the world melt due to climate change had increased by 50 percent in 30 years, according to a new study based on satellite data.
“We know that not all meltwater reaches the oceans immediately,” lead author Dan Shugar, a geomorphologist and associate professor at the University of Calgary, said in a statement.
“But until now there was no data to estimate how much was stored in lakes or groundwater.”
The findings, published Monday in Nature Climate Change, will help scientists and governments identify potential dangers to communities downstream of these often unstable lakes, he said.
They will also improve the accuracy of estimates of sea level rise through a better understanding of how, and how quickly, water discharged from glaciers reaches the sea.
Between 1994 and 2017, the world’s glaciers, especially in high mountain regions, shed around 6.5 trillion tonnes in mass, according to previous research.
“In the last 100 years, 35 percent of global sea level rise came from melting glaciers,” Anders Levermann, a climate professor at the Potsdam Institute for the Impact of Climate Change, told AFP.
The other main sources of sea level rise are ice sheets and the expansion of ocean water as it warms.
Glacial Lake Bursts
Earth’s average surface temperature has risen 1 degree Celsius since pre-industrial times, but high mountain regions around the world have warmed at twice that rate, accelerating the melting of glaciers.
Unlike normal lakes, glacial lakes are unstable because they are often dammed by ice or sediment made up of loose rocks and debris.
When the accumulation of water passes through these accidental barriers, massive flooding can occur downstream.
Known as glacial lake outbursts, these types of floods have been responsible for thousands of deaths in the last century, as well as the destruction of villages, infrastructure and livestock, according to the study, published in Nature Climate Change.
The most recent recorded incident was the outbreak of a glacial lake that cut through Pakistan’s Hunza Valley in May.
In January, the United Nations Development Program estimated that more than 3,000 glacial lakes have formed in the Hindu Kush-Himalaya region, and 33 pose an imminent threat that could affect up to 7 million people.
The new study, based on 250,000 scenes from NASA’s Landsat satellite missions, estimates the current volume of the glacial lake at more than 150 cubic kilometers (37 cubic miles), equivalent to one-third the volume of Lake Erie in the United States or twice the volume of Lake Geneva.
A decade ago, it would not have been possible to process and analyze that volume of data, Shugar said.
© Agence France-Presse
