A Vital Atlantic Ocean System Could Collapse Sooner Than Previously Thought

Climate change is slowing down the Atlantic Meridional Overturning Circulation, a key ocean “conveyer belt.” New research finds it could collapse completely by 2060.

By Siri Chilukuri / Grist 31 Jul 23 ScheerPost

Oceans all over the world rely on a delicate balance of different elements to remain stable: Temperature, salinity, pH, and pressure all combine to create the complex bodies of water that maintain conditions for marine life and define the planet. Climate change has altered those conditions, though, by warming oceans to record-high temperatures and introducing more fresh water through sea-ice and glacier melt.

Now, new research published on Tuesday warns that a vital Atlantic Ocean system could collapse by 2060, setting off one of the planet’s tipping points, or potential points of no return. That collapse could eventually spell catastrophe for the people who live in countries that border the Atlantic Ocean, leading to increased sea-level rise in the United States, decreased temperatures and altered storm patterns over Western Europe, rejiggered climate and agricultural zones, and hotter ocean temperatures in the Caribbean.

The study, published in the journal Nature Communications, contradicts findings from the Intergovernmental Panel on Climate Change, or IPCC, the United Nations’ scientific collaboration that publishes reports on the state of climate change. The group’s latest assessment, released last year, found the collapse of the group of Atlantic Ocean currents to be unlikely given the group only acknowledges weakening of the Atlantic Meridional Overturning Circulation, or AMOC, starting in 2004. The report notes that scientists cannot say when or if a collapse will happen, since they state even the decline prior to the 2000s cannot necessarily be attributed to climate change.

We absolutely have deep respect for the IPCC report,” Susanne Ditlevsen, a statistician at the University of Copenhagen and co-author of the study, told Grist. “When we first started, we had this idea that we could use this method that’s data-based, to kind of confirm what the IPCC report is saying. So when we actually got our first results, we were very surprised, and we didn’t believe them.”

The AMOC is a thick band of water that travels from the Gulf of Mexico north along the southeastern U.S. before heading up the western edge of Europe, carrying mild temperatures with it, and onward toward Greenland and Iceland. Once there, the current is infused with heavy, cold, and salty water that then sinks, traveling back down the coast of the U.S. This system provides what one expert with the National Oceanic and Atmospheric Administration, or NOAA, called “symmetry” to temperatures in the North and South hemispheres.

But as carbon dioxide levels rise, temperatures increase, and ice melts in the Arctic, this current is being inundated with fresh water, throwing it out of balance. This has led to a weakening of the AMOC, which recently saw its slowest point in 1,600 years in 2021.

If the web of Atlantic Ocean currents stopped, it would constitute one of the Earth’s tipping points, which signal a dramatic, potentially irreversible shift in the condition of the planet — and its habitability for humans. A study last year found that the planet may have already passed a few tipping points, including tropical coral die-off and the beginning of the Greenland ice-sheet collapse, at just 1.1 degree Celsius (1.9 degrees Fahrenheit) of warming. ……………………………………… https://scheerpost.com/2023/07/31/a-vital-atlantic-ocean-system-could-collapse-sooner-than-previously-thought/