A new study has revealed alarming changes in over 7,500 lakes in western Greenland, which have shifted from being carbon sinks to carbon sources due to extreme climatic conditions. The research, published in the Proceedings of the National Academy of Sciences (PNAS), highlights the profound ecological transformation of these vital ecosystems caused by atmospheric rivers (ARs) and other climate extremes in recent years.
In September 2022, a series of atmospheric rivers long, narrow regions in the atmosphere that carry large amounts of water vapor struck western Greenland, causing record-breaking heat followed by rains. These events significantly altered the physical, chemical, and biological characteristics of the region’s lakes. In addition, the impact of Hurricane Fiona further raised temperatures and contributed to the unprecedented melting of the Greenland Ice Sheet, adding to the disruption.
These extreme climatic events have had a cascading effect on the lakes’ ecosystems. The heat and rain led to the thawing of permafrost, which had stored large amounts of organic carbon. As a result, carbon, iron, and other elements were released into the lakes, transforming them in ways that haven’t been seen in thousands of years.
The lakes, previously acting as carbon sinks absorbing carbon dioxide have now turned into carbon sources, releasing more than 350% more carbon dioxide into the atmosphere. Additionally, methane concentrations were 72% higher in August 2023 compared to the same period in 2014. The water, once blue, turned a dark brown within just one year, and the reduced light penetration has led to a decline in plankton biodiversity, disrupting the region’s carbon cycle.
These ecosystem changes are not just an environmental concern but also have direct implications for local communities. Many Greenlandic residents rely on these lakes for drinking water, and the transformation of the lakes has led to problems with water taste, odor, and potential health risks.
The study highlights the long-lasting effects that compound climate events can have on ecosystems, citing the historical example of California’s mega flood in 1861-62 and its long-term drought, which devastated the state’s economy. Similarly, the scientists warn that the ongoing changes to Greenland’s lakes could have significant ecological and economic ramifications.
The lakes’ transformation remains persistent as of July 2024, and it’s unclear whether they will revert back to their original state. However, scientists stress the importance of understanding and adapting to these unpredictable climate events in future planning.
The research underscores the urgent need for global efforts to address climate change and integrate potential risks into future environmental and adaptation strategies to protect ecosystems like Greenland’s lakes.