West Greenland is home to tens of thousands of blue lakes that provide residents drinking water and sequester carbon from the atmosphere. Yet after two months of record heat and precipitation in fall 2022, an estimated 7,500 lakes turned brown, began emitting carbon and decreased in water quality, according to a new study.
Led by Fulbright Distinguished Arctic Scholar and University of Maine Climate Change Institute Associate Director Jasmine Saros, a team of researchers found that the combination of extreme climate events in fall 2022 caused ecological change that “pushed Arctic lakes across a tipping point,” they wrote in a paper published in the the Proceedings of the National Academy of Sciences (PNAS). By July 2023, less than one year later, the physical, chemical and biological properties of these lakes were altered, a widespread transformation that typically occurs over hundreds of years, Saros said. Their results were shared with nearby communities.
Greenland normally experiences snow in the fall, but the spike in temperatures caused the precipitation to fall as rain instead, according to the study. The heat also caused permafrost — frozen soil that stores a significant amount of organic carbon — to thaw, releasing an abundance of carbon, iron, magnesium and other elements. As rain fell in record amounts, it washed these newly exposed metals and carbon from soil into lakes across Greenland’s western region, turning them brown.
Read more at University of Maine
Image: Researchers sample a lake near Kangerlussuaq, Greenland, that browned after the extreme events. (Credit: Photo by Adam Heathcote)
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