The currents of the Meridional Atlantic Ocean (AMOC) are vital in transporting heat from the tropics to the Northern Hemisphere, but new research shows that climate change could trigger the AMOC much faster than we expected.
That could have a major impact on the planet in terms of weather patterns, sustaining agricultural practices, biodiversity, and economic stability across large areas of the world affected by AMOC.
The problem is the rate at which the Earth is warming and melting the ice in the Arctic: according to the researchers’ new models, this rate of temperature rise means the risk of colliding on the tipping point for the AMOC is becoming an urgent concern now. .
(University of Copenhagen)
“It’s disturbing news,” says physicist Johannes Lohmann, of the University of Copenhagen in Denmark. “Because if this is true, it will reduce our safe workplace.”
Lohmann and his colleague Peter Ditlevsen modified an existing ocean climate change model to study the impact of a higher rate of freshwater inputs into the North Atlantic Ocean, driven by rapid melting of Greenland ice sheets.
The model showed that a faster rate of freshwater conversion could deactivate the AMOC much faster. In a tipping situation due to such a rate, the rate at which a change occurs, rather than a specific threshold, is more important – and once the tipping point is reached, there is no return.
In other words, the speed at which we push out greenhouse gases and melt ice in Greenland leaves us with very little room for maneuver when it comes to protecting the climate systems that monitor global weather patterns. The same problem could threaten other climate subsystems around the world as well, the researchers say.
“These tipping points have previously been demonstrated in climate models, where meltwater is slowly introduced into the ocean,” Lohmann told Gizmodo’s Molly Taft. “In reality, an increase in meltwater from Greenland is accelerating and cannot be considered slow.”
The AMOC acts somewhat like a large, curved conveyor belt of seawater, redistributing water and heat around the Northern Hemisphere as water temperature, salinity, and relative pressure change. It is partly why European winters are relatively mild even at higher latitudes.
Although the location of the AMOC is not clear, it has been slowing down in recent years, and this new study suggests that the faster climate change, the greater the which is the danger of these streams. The flow of cold fresh water from Greenland is likely to stop warm water from spreading north, scientists believe.
Modeling climate change is complex, with so many things to note, and Lohmann and Ditlevsen themselves acknowledge that more work needs to be done to find out exactly what the details of this situation are. caused by rate.
However, they hope it is a reminder of just how urgent the climate crisis is now: our targets to reduce greenhouse gas emissions must be as ambitious as possible, no matter what. a situation that ends at the Atlantic. It is very likely that we do not have a margin for error.
“Due to the chaotic dynamics of complex systems the required level of parameter change is not well defined, which severely limits the prediction of long-term qualitative behavior,” the researchers wrote in their paper .
“The results show that the safe operating space of elements of the Earth’s system in terms of future emissions could be less than previously anticipated.”
The research was published in PNAS.