Scientists warn that the Gulf Stream may be about to collapse: what are the consequences

The Gulf Stream is an offshoot of a complex system known as the Atlantic Oblique Circulation – or AMOC for its English acronym.

In short, this massive flow of ocean water is divided into two main phases (See details in the infographic below).

The first takes place in the southern Atlantic Ocean, between South America and Africa. In this region closest to the equator, the highest incidence of solar radiation leads to a warming of the surface column of the sea.

Thanks to the wind system typical of the region, these warmer waters are carried into the North Atlantic Ocean, even as far as Greenland and the North Pole.

In this context, the Gulf Stream passes near the eastern coast of North America, starting in the Gulf of Mexico and distributing heat in these locations.

“We have to remember that 70% of our planet’s surface is made up of water, which has a high heat-retaining capacity,” explains physical oceanographer Olga T. Sato, associate professor at the University of São Paulo’s Institute of Oceanography. Paolo (University of the South Pacific).

Namely: this heat generated in the equatorial region is literally transferred to the colder parts of the globe, to the north. This is necessary for this region to have more moderate temperatures and to be habitable by humans and other species.

The second stage of Amok takes place in the vicinity of Greenland. There, the cold, dry temperature cools the water and “expels” the salt from the part of the liquid that ends up freezing.

As a result, the water remaining there acquires a different property: it becomes colder and saltier.

“And this is important, as intensity controls temperature and salinity in the ocean,” adds Sato.

That is, the part of the water that becomes cooler and “salty” tends to submerge and fill the sea floor.

Gradually – and over thousands of years – this deep-sea plume is making its way into the South Atlantic and even into other oceans.

Still – on the one hand, warm surface waters coming from the south are pushed to the north by winds. On the other hand, cold, salty waters coming from the north sink and flow south – a real belt is formed that guarantees part of the planet’s climatic balance.

But what if this system collapses?

There is a consensus among specialists in this field that the climatic changes observed in recent years and projected in the future are caused by human action – in particular, by the emission of carbon dioxide from the burning of fossil fuels.

When it comes to AMOC, global warming also has direct consequences.

The cooling of ocean waters occurring in Greenland tends to diminish as the climate warms.

And the melting of ice in this area – another consequence of the warming temperatures – makes the water less salty.

All of which can affect the density process, which allows cold, salty water to sink and move south.

The interruption of this process could represent the collapse of Amok – after all, we are talking about a belt here, where the flow of water depends on this complex sequence of events.

“Several measurements taken since 2004 show us that Amok is weakening,” warns geographer Karina Lima, a doctoral student and climate researcher at the Federal University of Rio Grande do Sul.

Over the past two decades, scientists have detected changes in the average temperature in Greenland and the Arctic, for example.

Other groups keep a close eye on how fast the water flows, or at what depth of the ocean this “exchanging of signals” takes place between warm waters to the north and cooler waters to the south.

“But, of course, this observation only covers a very short period of time and it would be necessary to obtain more stable records in order to be able to understand Amoc’s behavior in the long term,” wonders Lima.

But it came again Post an article From the University of Copenhagen, Denmark, in the journal Nature Communications.

Through a series of statistical calculations, the authors estimate that Amok’s collapse could occur later this century, if carbon dioxide emissions continue at the current rate.

According to them, the cessation of this ocean current will occur between 2025 and 2095.

It must be said that the new study was received with reservations by the academic community. In a report for BBC News, Professor Penny Holiday from the UK’s National Oceanographic Centre, said there was no strong evidence that the AMOC was slowing.

According to her, it is known that there is a possibility that Amoc will stop working as we know it today, but it is very difficult to be sure of that until now.

John Robson, a meteorologist at the University of Reading, also in the UK, agrees. According to him, projections as to when the Amok collapse will occur are still not entirely certain, and a time window as close as 2025 should be viewed with suspicion.

But what if your mom stops working? What will happen to the climate?

Post-apocalyptic movie the day after tomorrowfrom 2004, in a world suffering from the consequences of global warming and subsequent cooling.

The entire premise of the story is based specifically on the eventual collapse of the Gulf Stream and, in a broader scenario, of Amoc.

In the plot, New York is suddenly devastated by tsunamis and severe cold snaps.

But in real life, things will not happen so quickly.

“I can say that the scenario will not be the same as what is happening in it the day after tomorrowwith catastrophic events very quickly,” says Sato.

The researcher adds: “The ocean takes time to respond to changes, which will feel slow and little by little.”

This is not the case that the final collapse of the AMOC will happen overnight, which may trigger a series of unexpected disasters – such as tsunamis, tornadoes, heat and cold waves – in a short period of time.

But some of the potential long-term consequences of disturbances in the Atlantic Ocean currents are relatively easy to predict. (See summary in the chart below).

The main reason is the cooling of parts of Europe and North America – after all, warm water from the South Atlantic will not get there.

“The forecast also indicates changes in precipitation patterns, with droughts in some areas and floods in others,” Lima adds.

According to the climate researcher, this may even affect our country, especially the Northeast region.

Speaking of Brazil, Some work suggests That this change in precipitation associated with the collapse of Amok will also reach the Amazon – and accelerate the transformation of these tropical forest regions into savannas.

The planet’s equatorial region could also experience more heat and rising ocean levels – which could be another warning for islands, coastal and coastal regions.

“Ocean heat waves can have very important economic consequences, such as affecting fish production,” says Sato.

Changes in precipitation patterns can also be a major problem in agriculture.

It should be noted that all these possible consequences of the collapse of AMOC carry a high degree of uncertainty and are the subject of fierce debate among specialists in this field.

Of course, large ocean currents tend to rearrange themselves in another way – the problem is that it is not known what the practical consequences of these changes in the flows of warm and cold waters around the world will be.

The USP professor points out that many of these shifts in environment and climate have already been observed in practice and are associated with various processes affected by climate change.

“We have to keep in mind that these systems are very complex and can have different impacts on society and the economy,” she recalls.

“This is not something that will only happen in the future. We can already see some effects today, and this will tend to get worse over the next 10 or 20 years,” adds the physicist-oceanologist.

Lima states that the only way to mitigate these risks is to reduce carbon dioxide emissions by reducing the use of fossil fuels, among a series of other urgent measures.

“And this requires a structural change in society. It is not easy and quick to migrate the entire energy matrix of the world to actually reduce emissions,” she assesses.

“This is the only way to stop global warming and reduce its consequences for the planet,” he concludes.