Recently, a study published in Nature Climate Change notes that the Atlantic Meridional Overturning Circulation (AMOC), is losing its stability.
According to the IPCC’s Report (AR6) released on August 9, it is very likely that AMOC will decline over the 21st century.
What is Atlantic Meridional Overturning Circulation?
- The AMOC is a large system of ocean currents.
- It is the Atlantic branch of the ocean conveyor belt or Thermohaline circulation (THC), and distributes heat and nutrients throughout the world’s ocean basins.
- AMOC carries warm surface waters from the tropics towards the Northern Hemisphere, where it cools and sinks. It then returns to the tropics and then to the South Atlantic as a bottom current.
- From there it is distributed to all ocean basins via the Antarctic circumpolar current.
What happens if Atlantic Meridional Overturning Circulation collapses?
- Gulf Stream, a part of the AMOC, is a warm current responsible for mild climate at the Eastern coast of North America as well as Europe.
- Without a proper AMOC and Gulf Stream, Europe will be very cold.
- Modelling studies have shown that an AMOC shutdown would cool the northern hemisphere and decrease rainfall over Europe. It can also have an effect on the El Nino.
- AMOC collapse brings about large, markedly different climate responses: a prominent cooling over the northern North Atlantic and neighbouring areas, sea ice increases over the Greenland-Iceland-Norwegian seas and to the south of Greenland, and a significant southward rain-belt migration over the tropical Atlantic.
- AMOC and THC strength has always been fluctuating, mainly if you look at the late Pleistocene time period (last 1 million years).
- The extreme glacial stages have seen weaker circulation and slowdown in AMOC, while the glacial terminations have shown a stronger AMOC and circulation.
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