Atlantic Meridional Overturning Circulation

Context

Recently, a climate study discovered that if the Atlantic Meridional Overturning Circulation (AMOC) collapses, Europe ought to face a dramatic and prolonged winter freeze, even in a global warming by greenhouse gasoline emissions.

About Atlantic Meridional Overturning Circulation (AMOC) 

• It is one of the most effective and complex structures riding Earth’s climate. 
• It is often likened to a giant conveyor belt that transports heat surface waters from the tropics northward and returns cold, dense water southward at depth.
• It regulates temperatures across the Atlantic basin and performs an essential function in global climate stability, sea-level patterns, and marine ecosystems.

Working of AMOC

• The AMOC is a key factor of the global thermohaline move. 
• Warm, salty water flows northward thru currents just like the Gulf Stream. As it reaches higher latitudes, it cools and becomes denser, sinking into the deep ocean and flowing back south. 
• It allows the distribution of heat and nutrients throughout the globe, influencing climate patterns from the Amazon to the Arctic.

Slowing of AMOC and the Tipping Point

• Recent studies propose that the AMOC has weakened notably since the mid-20th century, and is predicted to gradually decrease by 18–43% by 2100.
• It is mostly driven by climate change, specially the influx of freshwater from melting Greenland ice, which disrupts the salinity and density gradients that power the contemporary.
• AMOC may be approaching a tipping factor, beyond which its disintegration may need to cause abrupt and irreversible climate shifts.
• AMOC has two ability tipping points — one linked to salt transport comments and another to deep ocean convection.

Climate Tipping Points  

• These are crucial thresholds in Earth’s structures—as soon as crossed, they are able to cause self-reinforcing feedback loops that lead to abrupt, irreversible, and doubtlessly catastrophic modifications.
• They occur while a small exchange in temperature or strain pushes a system — like an ice sheet, rainforest, or ocean current — into a substantially specific state.

Key Tipping Elements at Risk

• Recent assessments have identified as a minimum 16 fundamental Earth system components that are at risk of tipping, along with:
  • Greenland and West Antarctic Ice Sheets;
  • Atlantic Meridional Overturning Circulation (AMOC);
  • Amazon Rainforest Dieback;
  • Arctic Permafrost Thaw;
  • Coral Reef Collapse;

Potential Consequences

• Europe can also face colder winters in spite of global warming, as warm currents fail to reach its shorelines.
• West Africa should see disrupted monsoon patterns, affecting agriculture and water security.
• Eastern North America might enjoy expanded sea-level rise.
• The Amazon and South Asia could be afflicted by altered rainfall patterns, increasing drought risk.

Source: The DTE

UPSC Mains Practice Question

Q. The new tri-nation partnership AUKUS is aimed at countering China’s ambitions in the Indo-Pacific region. Is it going to supersede the existing partnerships in the region? Discuss the strength and impact of AUKUS in the present scenario. (2021)

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