The AMOC is a system of ocean currents that carry warm water from the tropics into the North Atlantic and bring cold water from the north to the south. Natural factors have led to the collapse of the conveyor belt. The collapse was a big part of the last deglaciation. Scientists have shown that AMOC is in danger because of global warming.
The study was conducted by German researchers and a professor at the University of So Paulo in Brazil. Nature Communications publishes an article about their findings.
Chiessi told Ag that the glaciers that cover the territories that now correspond to Canada and the northern United States released a lot of ice into the Atlantic due to ocean surface warming.
The continental deposits were deposited by the melting of the ocean's ice. He said that scientists were able to establish for the first time that there was warming in the region before the mass iceberg release.
The melting of the ice changed the composition of the ocean at high latitudes in the north. The region between Canada and Greenland is a sensitive part of the AMOC.
The conveyor belt carries water from the south to the north. At high latitudes of the North Atlantic, the surface water becomes heavier and sinks down the water column. The deeper, colder and denser water is forced to return to the surface by an upwelling. Chiessi said it warms up, loses density and completes the circulation.
A huge amount of water is transported by AMOC. Itaipu, the world's second- largest hydroelectric plant, has a power output of about 100,000 kilowatts. In Brazil, the climate is influenced by the distribution of this energy. The collapse of circulation causes a redistribution of energy that alters the climate.
Between 71,000 and 12,000 years before the present, AMOC collapsed. According to Chiessi's studies, the collapses caused a huge increase in the amount of rain in Northeast Brazil and a huge decrease in the amount of rain in Venezuela. There has been a decrease in the amount of rain in the tropics.
The researchers were able to establish the sequence of events that led to the collapse of AMOC by discovering that the North Atlantic warmed at high latitudes.
The process begins with a small weakening of AMOC, which leads to warming at high latitudes of the North Atlantic. The glaciers are melting due to the warming and releasing armadas of ice. The surface water is less salty in the region as the ice falls. Chiessi said that the surface water isn't dense enough to sink.
The monitoring of AMOC shows that it is no longer strong. Warming of the planet's surface is one of the main reasons. The causes are related to the rising levels of greenhouse gases.
The weaker AMOC is thought to cause warming at high latitudes of the North Atlantic, which will cause glaciers to melt. The climate crisis could be worsened by this.
More information: Lars Max et al, Subsurface ocean warming preceded Heinrich Events, Nature Communications (2022). DOI: 10.1038/s41467-022-31754-x Journal information: Nature Communications
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