Scientists analysed a quarter-million NASA satellite images to assess how the lakes formed by melting glaciers have been impacted by global warming over the past 30 years. That glaciers are melting is well established by science, but where all that water is going has not been well-studied.
The researchers found that the amount of meltwater held in glacial lakes worldwide has increased by slightly over 50 percent. “We have known that not all meltwater is making it into the oceans immediately,” lead author Dan Shugar, a geomorphologist and associate professor at the University of Calgary, said in a statement, according to Phys.org.
“But until now there were no data to estimate how much was being stored in lakes or groundwater,” he added. The research showed that between 1990 and 2018, the number of glacial lakes rose by 53 percent and this expanded the amount of the Earth the lakes cover by about 51 percent. This amounts to 14,394 glacial lakes spread over nearly 9,000 square km (3,475 square miles) of the planet’s surface.
The findings were published Monday in Nature Climate Change, and will help scientists and governments identify potential hazards to communities downstream of these often unstable lakes, he said.
Up until a few years ago, it wouldn’t have been possible to do this kind of research because computers weren’t powerful enough to work through a world’s worth of data and 250,000 satellite images, according to CBC Canada.
The researchers were able to calculate the total volume of water being held in all the glacial lakes at an astounding 158 cubic kilometers (5.58e+10 tons) of water.
“Our findings show how quickly Earth surface systems are responding to climate change, and the global nature of this,” said Stephan Harrison, a professor of climate and environmental change at Exeter University, reports MSM.
“More importantly, our results help to fill a gap in the science because, until now, it was not known how much water was held in the world’s glacial lakes.”
Source of water and a threat
Many of the world’s people, particularly in Asia and South America, depend on meltwater lakes for an important source of fresh water. But these lakes also present a substantial risk.
There is a growing threat from outburst floods that can tear down villages, wash away roads and destroy pipelines and other infrastructure. This is because unlike a normal lake, glacial lakes can form on top of, in front, beside or even underneath a glacier. These types of formations make the lakes very unstable.
The research paper cites several threats from outburst flooding, including hydroelectric power plants in the Himalayas; the Trans-Alaska pipeline, and major highways such as the Karakoram highway between China and Pakistan.
“Such glacial lake outburst floods, or GLOFs, have killed tens of thousands of people over the past century and destroyed valuable infrastructure such as hydroelectric power schemes,” said Harrison.
