Extreme Climate Impacts From Collapse of a Key Atlantic Ocean Current Could be Worse Than Expected. New Study Warns Disruption of the Atlantic Meridional Overturning Current could freeze Europe, scorch the Tropics and increase Sea Level Rise in the North Atlantic. The tipping point may be closer than predicted in the IPCC’s latest assessment. Bob Berwyn February 9, 2024 A new study affirms that a critical system of Atlantic Ocean currents that shunt warm and cold water between the poles is “on course” to a tipping point. If the Atlantic Meridional Overturning Circulation fails because of increasing freshwater inflows from melting ice sheets and rivers swelled by global warming, the authors said it would disrupt the climate globally, shifting Asian monsoon rainfall patterns and even reversing the rainy and dry seasons in the Amazon. “It’s a global shift,” saidUtrecht University climate and physics researcher René van Westen, co-author of the research published today in Science Advances. Along with changes in rain distribution, an AMOC collapse could also make some other related ocean currents in the Atlantic, like the Gulf Stream, “partly vanish,” he said. “This leads to a lot of dynamic sea level rise, up to a meter in the North Atlantic under an AMOC collapse,” he said. “And you need to add that on top of the sea level rise already caused by global warming. So the problems are really severe.” The East Coast of the United States would be one of the regions most affected by rising sea levels if the AMOC shuts down, he explained, because warming waters, which expand and increase sea level, would pile up there instead of flowing northward. Warming coastal oceans can also contribute to extreme heat waves over land and fuel more intense storms and rainfall. Without warm water flowing toward the Arctic, he added, winter sea ice could expand as far south as England, and some regions of Europe would quickly dry out and cool by as much as 1.5 degrees Celsius per decade.
Some of the projected impacts would be nearly impossible to adapt to, said Peter Ditlevsen, an ice and climate researcher with the University of Copenhagen Niels Bohr Institute and the author of a 2023 paper in Nature Communications that warned of a mid-century AMOC tipping point. “A lot of discussion is, how should agriculture prepare for this,” he said. But a collapse of the heat-transporting circulation is a going-out-of-business scenario for European agriculture, he added. “You cannot adapt to this. There’s some studies of what happens to agriculture in Great Britain, and it becomes like trying to grow potatoes in Northern Norway.” Under the current global warming trend, “It will be about 1 to 2 degrees Celsius warmer by 2050, and then maybe the AMOC tips and results in a slight cooling,” he said. The impact on the average global temperature wouldn’t be extreme, but Western Europe could cool to pre-industrial levels, and would get substantially less precipitation, he added. Other parts of the planet will warm faster, especially the southern hemisphere and tropics, since the heat transport system won’t be able to convey the increasing ocean warmth northward, he added. “It’s not science fiction,” van Westen said. Alarmist or not, “We need to show this is not only the Hollywood blockbuster, ‘The Day After Tomorrow.’ This is real, this can happen. And I think it’s important and urgent to keep saying to people, okay, we need to really tackle our emissions.” The AMOC distributes both warmer and colder water between both poles via a network of deep and near-surface ocean currents. The twin engines for the network are at high latitudes, where dense, cold and salty water sinks deep and pushes water horizontally across the seafloor. Those dynamics maintain the Circulation’s strength and the relative warmth of the Northern Hemisphere. The new study takes a detailed look at what happens when the balance is disrupted by greater quantities of freshwater flowing into the ocean, and the findings are a “major advance in AMOC stability science,” said Stefan Rahmstorf, head of earth system analysis with the Potsdam Institute for Climate Impact Research, and a professor of physics of the oceans at Potsdam University. The last AMOC breakdown occurred about 12,000 years ago and most climate scientists think it triggered the Younger Dryas cold event around the northern Atlantic, during which temperatures over Greenland dropped by 4 to 10 degrees Celsius in a matter of decades and glaciers temporarily advanced, while drier conditions spread across parts of the Northern Hemisphere......in the meantime, the United States is about to elect a raving fascist idiot as president who wants to negate all of the green reforms already implementeed and "drill baby drill", and there's invasions, war and violence everywhere - the world is going mad! https://insideclimatenews.