Potential AMOC Collapse Declared an ‘Existential Threat’ by Iceland

IN NEWS: Potential AMOC Collapse Declared an ‘Existential Threat’ by Iceland

ANALYSIS

1. Why AMOC Is in the News

• Iceland has formally declared the potential collapse of the Atlantic Meridional Overturning Circulation (AMOC) as a national security and existential threat, according to Reuters.
• This marks the first instance of a climate-specific phenomenon being presented to Iceland’s National Security Council as an existential threat.

2. Significance of AMOC for Europe

• AMOC drives warm tropical waters toward the Arctic, ensuring milder winters in Europe.
• A collapse could bring:
  • Modern-day ice-age-like conditions in northern Europe
  • Harsh, prolonged winters
  • Increased ice and snow
  • Severe disruptions to food security, energy systems, and maritime transport

3. Indicators of AMOC Weakening

• Accelerated Greenland ice sheet melting is a key driver behind AMOC slowdown.
• Scientists indicate collapse could occur at any time between early and late 21st century.
• As a climate tipping element, AMOC may undergo irreversible transformation once a threshold is crossed.

4. Scientific Findings

• Nature Communications (2023):
  • AMOC monitored continuously since 2004 via moored instruments, submarine cable electrical currents, and satellites.
  • Decline seen from 2004–2012; long-term SST (1870–2020) suggests early warning signs since 1970.
  • Estimated AMOC transition window: 2037–2109.
• Potsdam Institute Report (Aug 28, 2025):
  • Deep overturning severely slows by 2100 and shuts down beyond it under high-emission pathways; possible also under intermediate or low-emission scenarios.
  • Expected impacts:
    • Extreme winter events in northwestern Europe
    • Summer drying
    • Shifts in tropical rainfall belts
• Nature (Feb 2025):
  • Calls for improved understanding of Southern Ocean and Indo-Pacific circulations.
  • Suggests AMOC could be more resilient than earlier predictions, reducing likelihood of immediate collapse but confirming ongoing weakening.

5. National Responses

• Iceland:
  • Ministries preparing for:
    • Food insecurity
    • Energy generation and distribution challenges
    • Impacts on sea transport
  • Work initiated on a disaster-preparedness policy.
• Norway:
  • Conducting additional research before classifying AMOC as a national security risk.

6. Historical Perspective

• The last AMOC collapse occurred before the last ice age, preceding the rise of agriculture and settled civilisation.

STATIC PORTION (Essential Concepts)

Atlantic Meridional Overturning Circulation (AMOC)

• A large-scale system of ocean currents circulating heat globally.
• Key functions:
  • Moderating temperatures in Europe
  • Influencing monsoon and rainfall patterns
  • Balancing global heat distribution

Climate Tipping Points

• Thresholds leading to irreversible, self-perpetuating changes in Earth systems.
• AMOC is one of Earth’s major identified tipping elements.

Subpolar Gyre

• A North Atlantic current system whose sea surface temperature patterns serve as AMOC stability indicators.

Early Warning Signals

• Loss of resilience
• Increased variability in ocean temperature
• Slower recovery from disturbances

Updated – 13 Nov 2025 ; 06:00 PM | News Source: Down to Earth