Greenland’s Crystal Blue Lakes Turned Brown

Context: According to a recent study published in the Proceedings of the National Academy of Sciences over 7,500 lakes in western Greenland have turned brown.

What Triggered This Transformation? – Unusual Weather Patterns in 2022

• Greenland typically receives snowfall from late August to September.
• But, in 2022, warmer temperatures caused rainfall instead of snow, leading to drastic environmental changes.
• Heavy rainfall washed carbon, iron, magnesium and other elements into lakes, altering their physical and chemical composition.
• Increased heat also thawed permafrost, which stores organic carbon and various minerals

Consequences of This Environmental Shift

• Water Quality Decline: Increased organic material in lakes affected their taste, odour and colour.
• Reduced Sunlight Penetration:
  • The darkening of lakes blocked sunlight, disrupting the ecosystem.
  • Phytoplankton, which play a critical role in absorbing carbon dioxide, were negatively impacted.
  • This reduced CO₂ absorption capacity, making lakes less effective as carbon sinks.

Shift from Carbon Sink to Carbon Source

• The lakes, which previously absorbed carbon, began releasing it instead.
• Carbon emissions from lakes increased by 350% due to the breakdown of organic material.

Role of Atmospheric Rivers

• Atmospheric rivers are long, narrow bands of moisture in the atmosphere that transport large amounts of water vapour from the tropics.
• They are sometimes called “rivers in the sky” and are responsible for significant precipitation events.

Climate Change Impact on Atmospheric Rivers

• A 2018 NASA study has predicted that atmospheric rivers will become more intense, longer, and wider due to rising global temperatures.
• By the end of the 21st century, atmospheric rivers could become 50-290% more frequent in regions like Greenland, western North America, East Asia, western Europe and Antarctica (Phys.com report).

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