The potentially catastrophic softening of the southern circulation of the Atlantic (a critical oceanic current), due to climate change, may be the salvation of the Amazon, in view of increasing temperatures.
The weakening of the southern circulation of the Atlantic may be reinforcing precipitation in the Amazon rainforest, reducing the risk that it reaches a break. The conclusion is from a study recently in the Arxiv.
The collapse of the southern circulation of the Atlantic – – and the transformation of the Amazon rainforest into Savana are two of the most serious breakthroughs that predict if global warming continues.
Can cause global and irreversible impacts.
The Amoc transports hot water from the equator to the poles to the surface of the sea and cold water in the opposite direction in the depths of the ocean, so the sea surface temperatures can provide some indications on the force of the current. If it stops, it may cause one in North America, a sudden and sharp descent of temperatures in northern Europe and serious monsoon disturbances throughout Asia.
At the same time, the increase in temperatures is drying the Amazonian tropical rainforest, pushing it to one where the forest goes from jungle to savannah.
This transition was Much of global biodiversity in dangerIt would impair the planet’s ability to absorb ongoing emissions and disturb the climate throughout South America.
Surprising stabilizing interaction
Surprisingly, the new study found that the softening of the amoc can preserve the Amazon rainforest, demonstrating a stabilizing interaction between two elements of rupture.
The research team detected a connection between the two phenomena from 1982 to 2022. The colder temperatures to the sea surface in the North Atlantic Ocean would lead to the strengthening of an air stream called the low level of Caribbean jet, increasing precipitation on the Amazon During the region’s May Setember Setember.
“We found that a weakening of amoc leads to an increase in precipitation and green vegetation in the southern Amazon rainforest during the dry season,” the investigation leader told New Scientist to New Scientist Annika Högnerfrom the International Institute for Applied Systems Analysis in Austria.
“Dry season is a critical period of the year when water stress is higher and can occur dry, and plays an important role in the stability of the tropical rainforest. This is why we can interpret this interaction that we see as a stabilizing interaction between two elements of break“.
The team found that this effect has pocked about 17% of the drying trend observed in the Amazon since 1982.
However, the study points out that, even with the stabilizing effect of a weakening of the amoc, the Amazonia is already becoming drier.
“It’s worrying every time we identify a mechanism where the earthly system helps us dampens the adverse impacts of man -made climate change. We shouldn’t wait for the land system to do it for us forever,” said Annika Högner.
“It’s mere causality”
But the theory presented by the new study does not seem to be consensual. To counteract the theory of the new study is the scientist Maya Ben-yamifrom the Potsdam Institute for climate impact investigation in Germany.
Speaking to New Scientist, the expert said the results do not show a link between Amoc and the Amazon: “I think the results are a teleconnection [ou uma] causality Between the temperatures of the North Atlantic Sea surface and precipitation in South America. But it is not a connection between Amoc and the Amazon. ”
David Armstrong McKayfrom the University of Sussex, in the UK, also fears that the indicators used to measure Amoc and Amazon may not accurately reflect the current state of these points of inflection.
This is because others Important variables, such as the impact of deforestation on the Amazon, were left out of the study.
“Whether the amoc is slowing or not, what we know is that it will slow down and potentially with greater warm -up and that in the past tended to push tropical monsoons to south, disturbing ecosystems and the global carbon cycle ”, Says the investigator.
Who can change the course of events is the man – adds McKay. For that, It is necessary to wage deforestation and greenhouse gas emissions as soon as possible.
