Climate Change-Led Greenland Lakes Transformation

 

In 2022, over 7,500 lakes in western Greenland underwent a dramatic transformation from crystal blue to brown. This change was triggered by extreme weather events, including heavy rainfall and warmer temperatures. The lakes, vital for local drinking water and biodiversity, began emitting carbon and suffered decline in water quality.

Extreme Weather Events and Their Causes

The transformation of Greenland’s lakes was primarily due to unusually high temperatures and precipitation. Typically, the region experiences snowfall in late summer. However, in 2022, rain replaced snow due to warmer conditions. This  led to the thawing of permafrost, which released organic carbon and other elements into the lakes. The extreme weather events occurred rapidly, causing changes that would usually take centuries.

Role of Atmospheric Rivers

• Atmospheric rivers played important role in the extreme weather experienced in Greenland.
• Defined as long, narrow regions in the atmosphere, these phenomena transport amounts of water vapour.
• While they contribute to freshwater supplies, intense atmospheric rivers can cause severe flooding and heat.
• Climate models suggest that as global temperatures rise, atmospheric rivers will become more frequent and intense, impacting regions like Greenland.

Impact on Lake Ecosystems

The influx of organic carbon and minerals transformed the physical and chemical properties of the lakes. By July 2023, the lakes exhibited noticeable changes in colour, odour, and taste. The increased dissolved organic material affected drinking water treatment processes, potentially leading to harmful byproducts. Moreover, reduced light penetration hindered phytoplankton growth, which plays a vital role in carbon dioxide absorption through photosynthesis.

Shift from Carbon Sink to Carbon Source

The transformation of the lakes resulted in increase in carbon dioxide emissions. The study noted a 350% rise in emissions as the lakes shifted from being carbon sinks to carbon sources. This change is concerning, as it contributes to the overall increase in atmospheric carbon levels, exacerbating climate change.

Broader Implications for Carbon Sinks

The findings from Greenland’s lakes are part of a larger trend affecting global carbon sinks. A recent study indicated that land-based carbon absorption has drastically decreased, marking the lowest levels since 2003. With natural carbon sinks like forests and oceans struggling to absorb carbon, the potential for rising atmospheric carbon levels is high. Current projections estimate a continued rise in global carbon dioxide emissions, further impacting climate stability.

website: popularscientist.com

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