Why is the World’s Strongest Ocean Current Slowing Down?

Mar 3, 2025, 23:02 IST

The Antarctic Circumpolar Current (ACC), the world’s strongest ocean current, is slowing down due to Antarctic ice melt. The influx of freshwater disrupts ocean salinity and density, impacting global climate and ocean circulation. Research using the GADI supercomputer reveals threats to marine ecosystems, climate stability, and carbon absorption capacity.

World’s Strongest Ocean Current Slowing Down
World’s Strongest Ocean Current Slowing Down

The Antarctic Circumpolar Current (ACC), the world's most powerful ocean current, is slowing down as the Antarctic ice sheets melt. The influx of freshwater into the Southern Ocean is altering its salinity and density, impacting global climate and ocean circulation.

Key Findings

Aspect

Details

Current Impacted

Antarctic Circumpolar Current (ACC)

Cause

Increased Antarctic ice melt leading to freshwater influx

Consequence

Disruption of heat, nutrients, and carbon dioxide distribution

Barrier Function

Prevents invasive species from reaching Antarctica

Research Tool

Australia's fastest supercomputer, GADI

Study Published In

Environmental Research Letters

Understanding the Antarctic Circumpolar Current (ACC)

The ACC flows from west to east around Antarctica and acts as a key component of global ocean circulation. 

  • It serves as a natural barrier, preventing invasive marine species from entering Antarctic ecosystems.
  • The ACC plays a crucial role in regulating global climate, heat transfer, and carbon dioxide absorption.

Why is the ACC slowing down?

  • Melting Antarctic Ice:
      • Rising temperatures are accelerating ice melt, leading to massive freshwater releases.
      • This alters the salinity and density of ocean water, disrupting circulation patterns. 
  • Impact on Ocean Circulation: 
      • The ACC is part of the global ocean conveyor belt, responsible for distributing heat and nutrients.
      • Disruptions could lead to increased climate variability and extreme weather events.
  • Changes in Marine Ecosystems:
    • A weaker ACC may allow non-native species like bull kelp and molluscs to enter Antarctic waters.
    • These species could threaten native wildlife, such as penguins, by altering food chains.

Scientific Approach

Researchers from the University of Melbourne conducted high-resolution simulations using GADI, Australia’s fastest supercomputer. Their climate model, ACCESS-OM2-01, analysed the effects of change:

  • Ocean temperatures
  • Salinity levels
  • Wind patterns

Contradiction with Previous Studies

  • Earlier research suggested that the ACC might accelerate due to increasing temperature differences across latitudes.
  • However, the new findings indicate that ice melt is the dominant factor in slowing the current.

Consequences of a Slower ACC

Impact Area

Potential Consequences

Climate

Greater climate variability and extreme weather events

Carbon Sink Function

Reduced ability of oceans to absorb carbon dioxide, accelerating global warming

Ecosystem Stability

Risk of invasive species altering Antarctic marine biodiversity

Ocean Circulation

Disruption of heat and nutrient distribution, affecting global marine life

Conclusion

The slowdown of the Antarctic Circumpolar Current is a pressing issue with far-reaching implications for climate stability, ocean health, and biodiversity. As Antarctic ice continues to melt, urgent global efforts are required to mitigate climate change and safeguard marine ecosystems. Ongoing research using advanced climate models will be critical in understanding and addressing these changes effectively.

Prabhat Mishra
Prabhat Mishra

Content Writer

    Prabhat Mishra is an accomplished content creator with over 2 years of expertise in education, national and international news, and current affairs. A B.Tech graduate with extensive UPSC preparation, he has qualified for the UPPCS 2022 Mains and Bihar 68th Mains, showcasing his deep understanding of competitive exams.

    He has contributed to top platforms like Mentorship IndiaIAS BABA, and IAS SARTHI, delivering engaging articles on trending topics and global affairs. As a content writer for Jagranjosh.com, Prabhat specializes in crafting high-quality, insightful content for the G.K. and Current Affairs section, driving engagement and providing value to a wide audience.

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