“Greenland’s Blue Lakes Turn Brown and Emit Carbon Dioxide: A Climate Crisis Unfolds”

In a groundbreaking study published by the University of Maine, researchers have discovered that thousands of crystal-clear blue lakes in West Greenland have turned a murky brown due to the effects of global warming. What’s even more alarming is that these lakes have now started emitting carbon dioxide into the atmosphere, a stark contrast to their previous role of absorbing CO₂.

The drastic changes in the lakes began in the fall of 2022, a time when Greenland typically experiences snowy conditions. However, record heat and rain caused by heat waves transformed the snow into rain, leading to the thawing of the island’s permafrost. This resulted in the release of carbon, iron, and other elements into the lakes, turning their pristine blue waters into a murky brown hue.

As the lakes darkened, less sunlight was able to penetrate the water, impacting the microscopic plankton living within them. The plankton, which play a crucial role in absorbing CO₂ through photosynthesis, saw a decline in their numbers. Conversely, the amount of plankton breaking down and releasing carbon increased, further exacerbating the emission of CO₂ from the lakes.

The researchers noted that while the browning of lakes is a phenomenon observed across the Northern Hemisphere, including the U.S., the rapid transformation of Greenland’s lakes is unprecedented. Normally, such widespread changes would take centuries to occur, but in this case, the lakes shifted from carbon sinks to carbon dioxide producers within a year.

Lead author of the study, Jasmine Saros, a professor of paleolimnology and lake ecology at the University of Maine, described the magnitude and rate of change as unprecedented. The findings of the study were published in the journal PNAS on January 21, 2025.

The root cause of this historic transformation can be traced back to an atmospheric circulation pattern in the fall of 2022, which connected atmospheric rivers from the subtropical and mid-latitude Atlantic to Greenland. These atmospheric rivers, known for transporting heat and water vapor, brought record heat to Greenland, causing temperatures to soar above average levels.

The researchers estimated that around 7,500 lakes in West Greenland turned brown and began emitting carbon dioxide following the atmospheric changes. Apart from the environmental implications, the transformation of these lakes also poses a threat to the drinking water supply of Greenland residents. The influx of dissolved organic carbon and nutrients from the permafrost could lead to bacterial growth, affecting the taste and smell of the water and potentially causing health issues.

Saros highlighted the potential risks associated with the dissolved materials interacting with water treatment processes, leading to the production of harmful byproducts like trihalomethanes, which are known carcinogens. The study authors expressed uncertainty about the lakes reverting to their original blue state, raising concerns about the long-term impact of these changes on the environment and public health.

Overall, the findings of this study shed light on the rapid and unprecedented effects of global warming on Greenland’s lakes, underscoring the urgent need for climate action to mitigate further damage to our planet’s ecosystems.