In the biggest investigation of glacial lakes, researchers using 30 years of NASA’s satellite information have discovered that the worldwide volume of these lakes has expanded by about 50% since 1990 due to glaciers dissolving and retreating.
The discoveries made will help scientists surveying potential danger to communities downstream of these often unstable lakes and help improve the accuracy of sea-level rise estimates.
Glaciers are withdrawing on a near worldwide scale, and this study gives researchers a clearer image of the amount of this water that has been stored in lakes.
Lead author Dan Shugar of the University of Calgary in Canada has said it is known that not all meltwater automatically hits oceans and until recently, there was no information to gauge what amount was being put away in lakes or groundwater. The study estimates current glacial lake volumes total about 33% of the volume of Lake Erie.
Shugar and his collaborators from governments and universities in Canada, the United States, and the United Kingdom, working under a grant from NASA’s High Mountain Asia Program, initially planned to use satellite imaging and other remote-sensing data to study two dozen glacial lakes in High Mountain Asia, the geographic region that includes the Tibetan Plateau and surrounding mountain ranges, including the Himalaya.
Shugar and his colleagues from governments and colleges in Canada, the United States, and the United Kingdom, working under a grant from NASA's High Mountain Asia Program, at first wanted to utilize satellite imaging and other remote-sensing data to examine two dozen glacial lakes in High Mountain Asia, the geographic district that incorporates the Tibetan Plateau and encompassing mountain ranges.
They wrote scripts in the Google Earth Engine to look only at High Mountain Asia. They then decided to look at all glacial lakes in the world. From that data, they were able to build a scale to estimate the volume of the world’s glacial lakes based on the area of this large population of lakes.
The team analyzed more than 250,000 scenes from satellite missions which were part of a joint NASA/U.S. Geological Survey program. In 2010 it would have been impossible to process and analyze this amount of data. By looking at the data in time-steps starting in 1990 to examine all the glaciated regions of the world and analyze how glacial lakes changed over that period. The only exclusion was Antarctica.
While water from melting glaciers stored in glacial lakes is a decently small contributor to overall sea-level rise, it has the ability to majorly impact mountain communities downstream of these lakes.
This is an issue in many locations where people live downstream from hazardous lakes, primarily in the Andes Mountains and areas like Bhutan and Nepal, where floods can be disastrous. thankfully, organizations such as the United Nations are aiding a lot of monitoring and mitigation work where they are lowering lake level to attempt and decrease the peril.
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