In the depths of the Atlantic Ocean, there’s a huge current that is the size of 8000 Mississippi Rivers. Its influence on the climate of the Earth is so significant that it affects the weather conditions from the Equator to Europe as well as crop production in Africa and rising sea levels along the East Coast.
Scientists believe that this vital energy flow could be shut off as the temperature rises A collapse of this vital current could cause catastrophic consequences across the globe.
Researchers have been attempting to determine the exact time at which the Atlantic may cross that tipping point. However, answering that question isn’t an straightforward task.
Then, a research study discovers that the abolition of the circulation, commonly referred to as the Atlantic meridional turning circulation or AMOC it could happen much earlier than scientists believed, perhaps within some years, due to the effects of the human-caused global warming.
“It’s an alarming consequence,” says Peter Ditlevsen Professor of Climate Physics of the University of Copenhagen in Denmark and co-author on the research. “It requires urgent actions. We have to cut emissions. We need to put more brakes on trains.”
Others have cautioned that the timetable for such fall — or when the AMOC will even collapse is still unclear because of the immense difficulty of understanding the ocean system, which spans many thousands of miles. Recent studies have indicated that an AMOC collapse is unlikely in this century.
The study is part of the growing number of studies that suggests crucial tipping points in the system of climate are extremely difficult to predict and that humans are altering the fundamental processes of Earth quicker than we be able to comprehend them. With the possibility of catastrophic effects, scientists suggest more research is needed to discover AMOC AMOC is more crucial than ever before.
“The AMOC is a bedrock of our climate system” claims Nicholas Foukal, an assistant scientist at the Woods Hole Oceanographic Institution who wasn’t involved in the research. “It is a way to distribute heat across the globe and it’s something we all think of as a given.”
A conveyor belt to heat
In terms of temperatures, Europe has a lot to be grateful to its AMOC for. Cities such as London or Paris are much warmer than comparable temperatures within North America.
“In Scandinavia, we have some sort of pleasant mild climate” Ditlevsen said. “And If you compare this to that of the U.S., we are situated in Alaska which is warmer as Scandinavia.”
Warmer winters in Europe are in large part due to the flow of heat that comes from AMOC. The current is carrying huge quantities of hot water south from Equator and travels north along to the East Coast of the U.S. before crossing over to Europe. This is where the water gets cool, releasing warmth into the air.
The salty, cold water is heavier and denser which causes it to sink close to Greenland. As a conveyor belt flow reverses back to the direction from which it came to flow towards the south, extending across the bottom of the ocean.
Researchers have discovered that this conveyor belt was shattered over time. About 12,000 years ago temperatures in Greenland abruptly dropped by around 18.3 degrees F. The reason for this is a sudden shut down of the AMOC and also demonstrates the potential consequences of an event that could be a tipping point for climate.
“A tipping point a significant consequence of a tiny shift,” Ditlevsen says. “It’s the moment you’re pushed up the edge. Once you’ve reached the cliff then you fall.”
Searching for the tipping point
To figure out where that tipping point could be, Ditlevsen analyzed ocean temperature records in the vicinity of Greenland in the last 150 years, and then ran statistical analyses to study the changes in temperature. The co-authors and he discovered rising temperature variations that they believe could be a sign that the AMOC is decreasing. Based on their research they believe that the AMOC could be in decline between 2025 between 2025 and 2095. This is a decade earlier than what other studies have shown.
While scientists are divided on the timing of this collapse, there’s a general agreement on the possible consequences. A collapse of the AMOC could trigger ripple effects throughout the world. In the meantime, temperatures in Europe could decrease, while temperatures in the tropics could rise, which could accelerate climate change that is already happening.
Rainfall is likely to drop throughout regions like the Sahel zone of Africa which could mean less production of crops for millions people. The summer monsoon is likely to decrease throughout Asia as sea level rises more quickly across regions like the Eastern U.S. The scientists have discovered that small changes in Atlantic circulation can have devastating consequences for marine life such as threats to endangered North Atlantic right whales.
“It’s going to impact agricultural production,” Foukal says. “It’s going to affect diseases especially in the equatorial zone. It will affect massive migration.”
If it’s still a huge issue
Yet, a collapse in the midcentury is not in line with the findings of other research studies discovered. A report by the Intergovernmental Panel on Climate Change concluded that the AMOC is not likely to break up in the next century.
“Whether it will end up falling apart remains a mystery,” Foukal says. “I believe that there’s some doubt.”
Foukal says that this latest study rely on temperature data from a tiny portion of the system, and does not accurately represent what might be the case for the entire current. It’s also important to determine the root of collapse in order to determine the time of collapse that Ditlevsen’s research did not consider.
When the AMOC shut down, Earth was emerging from an glacier. Scientists believe that a huge quantity of fresh water from melting glaciers was pumped into the Atlantic, causing interference with the belt conveyor. Fresh water is less heavy than salt water, and could hinder the sinking motion which drives the entire flow.
The same thing could happen in the future, in the event that humans continue heating the planet through using fossil fuels. The ice is melting in Arctic and Greenland’s ice sheets melt in a rapid rate and also giving fresh seawater to the Atlantic. However, Foukal says that scientists are trying to determine if this is enough to cause the entire ice sheet to collapse.
The more likely scenario, he suggests could be that the AMOC may weaken in the coming century. This could cause some of the same devastating effects as a collapse, however, to a lesser degree. Certain studies have indicated that the weakening of the system is already taking place However, some researchers believe that due to the regular changes in the current, it could take longer to arrive at that conclusion.
The first direct observations of measurements of the Atlantic circulation have been conducted since 2004. With the lengths and depths of the area that AMOC is able to cover, it’s difficult to keep track of it. However, with the possibility of massive impacts, scientists researchers believe that further research is more crucial than ever before -along with swift action to limit the amount the planet is warming.
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