A key component of the ocean currents that criss-cross the North Atlantic Ocean is approaching a “tipping point” which, according to a new study, could lead to a collapse of the entire Sea and Ocean system. This situation would likely result in a catastrophic shift in the current climate crisis across the Northern Hemisphere – one eerily like the one depicted in Art Bell and Whitley Strieber’s 1999 book The Coming Global Superstorm.
However, this study does offer an early warning indicator for that tipping point that climate researchers can keep a weather eye out for.
Using a simulation called the Community Earth System Model (CESM), climate researchers with the Institute for Marine and Atmospheric Research Utrecht at Netherlands’ Utrecht University discovered that the ocean current responsible for transferring warm water from the tropics to the coast of northern Europe, the North Atlantic current, could not only slow drastically but also stop entirely if enough fresh water from Greenland’s melting glaciers were to flood the region.
While the numerous unknown variables on the road to such a scenario prevent the accurate prediction of when such an event might occur, the study’s simulation showed that ocean circulation in the North Atlantic “could fully shut down within a century of hitting the tipping point, and that it’s headed in that direction,” according to an article penned by the study’s authors that was published in The Conversation. “If that happened, average temperatures would drop by several degrees in North America, parts of Asia and Europe, and people would see severe and cascading consequences around the world.”
As part of the network of currents that comprise the Atlantic meridional overturning circulation (AMOC), the North Atlantic current—also known as the Gulf Stream—zig-zags northward from the west coast of Africa across to the Caribbean where it picks up warm tropical waters, and then tracks northeast towards northern Europe.
Under normal circumstances, the warm water from this southern stream cools when it meets the currents flowing south from the Arctic, causing the water to sink into the depths where it joins another current that runs southward, deep under the Atlantic, to continue its three-year journey through the world’s oceans.
However, the accelerated melt of glaciers in Greenland has already caused a large amount of fresh water to flood into the ocean where this downward convection takes place, and this fresh water, being less dense than salt water, inhibits the sinking of the current’s waters, slowing the flow of the entire system.
Although previous studies have indicated that a shutdown scenario is likely to happen if Arctic ice continues to melt, this new study used a version of the CESM simulation that is more detailed than the models used for earlier studies. The study involved adding progressively larger amounts of fresh water into the simulation until the mechanism of the AMOC reached a tipping point, after which “the conveyor belt shuts down within 100 years,” according to the authors. “The heat transport toward the north is strongly reduced, leading to abrupt climate shifts.”
The resulting shifts illustrated in the simulation were not subtle: “parts of the continent changed at more than 5 degrees Fahrenheit (3 degrees Celsius) per decade,” according to the authors, a shift more drastic than the current temperature increase of 0.2°C (0.36°F) per decade caused by global warming. Norway saw an even more severe drop, with the temperature in parts of the country plunging by 20°C (36°F). Conversely, the backup of warm water caused temperatures to increase by a few degrees in the Southern Hemisphere.
“The conveyor belt shutting down would also affect sea level and precipitation patterns, which can push other ecosystems closer to their tipping points,” the authors warn. “For example, the Amazon rainforest is vulnerable to declining precipitation. If its forest ecosystem turned to grassland, the transition would release carbon to the atmosphere and result in the loss of a valuable carbon sink, further accelerating climate change.”
Perhaps the most important part of the study is that the researchers have identified a threshold in the levels of salinity in the waters of the North Atlantic that could act as early warning signal for climatologists that would precede the current’s tipping point. Once this threshold is reached, “the tipping point is likely to follow in one to four decades.”
“The climate impacts from our study underline the severity of such an abrupt conveyor belt collapse,” the authors conclude. “The temperature, sea level and precipitation changes will severely affect society, and the climate shifts are unstoppable on human time scales.
“It might seem counterintuitive to worry about extreme cold as the planet warms, but if the main Atlantic Ocean circulation shuts down from too much meltwater pouring in, that’s the risk ahead.”
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This wouldn’t surprise me in the least. We humans are the culmination of millions of years of physical evolution and yet our emotional maturation hasn’t kept pace. Our “advanced” society in the US is so extrinsic that the problem won’t be tackled on our part until people in D.C. and the rest of the eastern seaboard are sitting for days on their roofs because the water isn’t receding. However, my pessimistic view will not keep me from trying to help raise awareness of our potential.
AS foretold by the MOTK
And the warnings will go unheeded.
The warnings will be unheeded true, but what if they are heeded? What is to be done? The fix is in there is no way that these climatic changes will be stopped or slowed in the next few hundred years. Carbon and methane and solar storms are working their wonders and changing to EVs will not change the results. Yes very wise to do what we can to clean up the industrial era messes but collectively we need to figure out how to survive and even prosper during these times of dramatically increasing changes. There are those who are offering possibilities of renewing, regenerating the land, turning the deserts green, moving underground to survive the storms and heat, ideas are abundant. We humans have the ability if only we could overcome our emotional immaturity, the experience of the “common enemy” might make that happen.