The coast of Greenland is dotted with thousands of lakes, their waters held back by walls of ice. But sometimes meltwater can break through and spill into the sea. The first study of its kind has found a 1,200 percent increase in the number of such lakes compared to what was previously recorded. The study was published on the Nature website, UNN reports.
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Greenland has more than 3,300 glacial margin lakes, which are natural reservoirs for meltwater outflow to the ocean. A sudden release of water can significantly affect ecosystems, landscape morphology, ice dynamics, and cause flood hazards. While large-scale studies of glacial lake outburst floods (GLOFs) have been conducted in many glacial regions, Greenland remains poorly understood, the study authors note.
In the new study, scientists used altimetry data to conduct Greenland's first inventory of water level changes in such lakes, studying more than 1,100 lakes between 2003 and 2023 and revealing a variety of lake behaviors.
"About 60% of the lakes show minimal fluctuations, and 326 lakes have dried up, together causing 541 observed glacial lake outbursts between 2008 and 2022," the researchers point out.
These GLOFs reportedly vary significantly in size and frequency, with the highest concentration in the northern and northeastern regions.
The scientists' results, as noted, show significant annual differences in the number of GLOFs with a notable peak in 2019, which coincides with a year marked by extreme water runoff.
"Our method revealed an increase in the number of drying lakes, by 1200% compared to existing historical databases. This highlights the significant underreporting of GLOF events and underscores the urgent need for a deeper understanding of the mechanisms and impacts of these dramatic events," the researchers note.
As New Scientist points out, the research could help better model sea level rise.