Iceland has officially recognized the potential collapse of the Atlantic Meridional Overturning Circulation (AMOC) as an existential threat to its national security

About Atlantic Meridional Overturning Circulation (AMOC)

• The Atlantic Meridional Overturning Circulation (AMOC) is a vast system of ocean currents driven by variations in salt content, temperature, and water density across the oceans. 
• It is often called the “ocean’s conveyor belt” because it continuously moves warm and cold water masses throughout the “Atlantic Ocean” with “between the tropics and the polar regions of the Atlantic”.

Mechanism of AMOC

• Warm Water Transport: AMOC carries warm water from the tropics to the northern part of the Atlantic Ocean.
  • This warm water releases heat into the atmosphere, which helps moderate the climate of Western Europe.
• Cooling and Density Increase: As the water cools and becomes denser in the North Atlantic, it sinks to the ocean floor.
• Southward Flow: This cold, dense water then flows southward along the ocean’s bottom, eventually returning to the tropics, completing the cycle.

Importance of AMOC

• Temperature Regulation: AMOC plays a vital role in regulating global temperatures by moving heat from the tropics to the poles.
• Influence on Weather Patterns: The circulation significantly impacts regional weather patterns, including rainfall and the tracks of storms.
• Global Climate Impacts: A slowdown or collapse of AMOC could lead to substantial changes in global climate, such as shifts in sea levels, precipitation patterns, and an increase in extreme weather events.

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Potential Impacts of AMOC Collapse

• Severe Cold in Northern Europe: A complete collapse of the AMOC could trigger a “dramatic regional temperature drop” in northern Europe, characterized by extreme cold, ice, and snow.
• Historical Collapse: Paleoclimate records suggest a major weakening of the AMOC during the Younger Dryas (~12,900 years ago), which caused abrupt cooling in the North Atlantic region before stable Holocene conditions allowed agriculture to emerge.
• Sea Level Rise: A weakened AMOC could contribute to increased sea level rise along the US East Coast and other coastal regions, exacerbating flooding risks and coastal erosion.
• Disruptions to Marine Ecosystems: Changes in ocean currents and temperatures due to an AMOC slowdown could have profound effects on marine life distribution and abundance, disrupting ecosystems and fisheries.

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