CONTEXT

Recent studies show that the AMOC could collapse between 2025 and 2095 due to the impact of anthropogenic emissions.

About the Atlantic Meridional Overturning Circulation (AMOC)

∙ It is a system of ocean currents that circulates water within the Atlantic Ocean, bringing warm water north and cold water south and is part of a complex system of global ocean currents.

∙ The global conveyor belt circulates cool subsurface water and warm surface water throughout the world. It plays a crucial role in moderating the climate of Europe and North America and influences temperatures near the Equator.

∙ The entire circulation cycle of the AMOC, and the global conveyor belt, is quite slow.

∙ It takes an estimated 1,000 years for a parcel of water to complete its journey along the belt.

∙ Even though the whole process is slow on its own, there is some evidence that the AMOC is slowing down further.

What if AMOC would collapse?

∙ AMOC is a kind of ‘switch’ for climate in the northern hemisphere, especially Europe.

∙ It would cause widespread cooling across the northern hemisphere and less precipitation in places such as Europe, North America, China and some parts of Russia in Asia.

∙ The excess heat due to a collapsed AMOC could lead to less rainfall over the Amazon rainforest and make it drought prone and dry, and it could potentially transform it to a savannah state.

∙ A slowdown of AMOC could hinder monsoon formation and rainfall in different regions.

∙ Rainfall in the Sahel region (the West African monsoon) could reduce, the summer monsoon circulation in South Asia and India could weaken; and there might be more winter storms in Europe.

∙ Weakening of the land-sea thermal gradient weakens the sea level pressure gradient and the summer monsoon circulation over the Indian region.

Tipping elements in the Earth’s climate system– These are the critical threshold for a system that influences the climate and ecology of the planet, indicating the point beyond which that system begins to undergo a large-scale irreversible shift.– Tipping elements include long-term loss of major ice sheets on Greenland and in Antarctica, large-scale ecosystem shifts for the Amazon rainforest and northern evergreen forests, species loss for coral reefs, shrinking Arctic sea-ice, and potential weakening of the AMOC etc.a. The collapse of AMOC could have a cascading impact on the stability of other tipping elements and climate systems of the earth.