A catastrophic scenario in which the Atlantic Ocean's currents collapse, causing chaotic weather and plunging Europe into a prolonged period of cold weather, appears to be unlikely to occur this century, according to a recent study.
In recent years, research has highlighted the concerns about the slowing and potential sudden collapse of the Atlantic end of the ocean conveyor belt system.
It carries rising warm water to the north and sinking cool water to the south, and plays a crucial role in the world's weather systems.
Researchers forecast a dramatic cooling of Europe while warming the rest of the world and rising sea levels on America's East Coast.
It's the scenario depicted in the 2004 fictionalized disaster movie "The Day After Tomorrow," which portrays a world where climate change triggers massive storms, flooding, and an ice age.
Researchers claim that this should be a reassuring discovery.
Researchers at the United Kingdom's Met Office and the University of Exeter conducted simulations using 34 different computer models of extreme climate change scenarios to determine if the Atlantic Meridional Overturning Circulation (AMOC) would collapse by the end of the century, as reported in a study published in the journal Nature on Wednesday.
The study revealed no simulation indicated a complete collapse before the year 2100, according to lead author Jonathan Baker, an oceanographer at the Met Office.
It's possible that this may happen at a later time, he stated. The currents have ceased functioning in the distant past. Nevertheless, the computer simulations are expected to be "reassuring" to individuals, Baker stated.
“However, this is not a reason for complacency,” Baker cautioned. “The AMOC is very likely to decline this century and this will lead to significant climate-related consequences.”
What changes is global warming bringing about in the Atlantic current?
The Atlantic current exists because warm water cools as it reaches the Arctic, resulting in the formation of sea ice. This process leaves behind salt, causing the remaining water to become denser and sink, being subsequently pulled southward.
The ice sheet, the Arctic engine behind the ocean conveyor belt, is slowing down. Previous studies predict it will eventually stop, with one of them suggesting this could occur within a few decades.
Baker stated that computer models and fundamental physics suggest that a second motor is activated along the Southern Ocean encircling Antarctica.
The winds there draw the water back to the surface, known as upwelling, where it warms, Baker stated. It's not as powerful, but it will likely sustain the current system, albeit weakened, through the year 2100, he stated.
, said Oregon State University climate scientist Andreas Schmittner, who was not involved in the research.
The Southern Ocean winds drawing up the deep water act “like a powerful pump that keeps the AMOC functioning even in extreme climate change scenarios,” Baker said.
As the Atlantic Meridional Overturning Circulation weakens, a weaker Pacific counterpart is likely to develop to make up for the loss, according to computer models.
What constitutes an AMOC shutdown?
It's still possible that this cold snap will occur, but it won't be a major news event of Europe experiencing a severe freeze, Baker said.
Scientists measure the Atlantic Meridional Overturning Circulation (AMOC) strength in a unit called Sverdrups. The AMOC's current strength is approximately 17 Sverdrups, having decreased by two from its level around 2004, with an observed trend of about 0.8 Sverdrups per decade, according to scientists.
One of the discussions within the scientific community revolves around the definition of an AMOC shutdown. Baker uses zero, but other scientists, who have expressed concerns about the implications of a shutdown, use approximately 5 Sverdrups. Three of Baker's 34 computer models dipped below 5 Sverdrups, but not all the way to zero.
That's why Levke Caesar and Stefan Rahmstorf, researchers at the Potsdam Institute for Climate Research and authors of a 2018 study warning about the potential shutdown, stated that this new work does not contradict their findings. It's essentially a matter of interpretation.
The collapse of the AMOC does not necessarily mean a shutdown of 0 (Sverdrups) overturning, and even if one were to interpret it as such, a significant weakening of the AMOC would still have a substantial impact.
“Models indicate a significant decline in the AMOC, which would have severe repercussions.”