The Arctic's main ocean current, the Beaufort Gyre, is changing rapidly due to climate warming - which could trigger a chain reaction that disrupts the system behind the Gulf Stream, the Atlantic Meridional Overturning Circulation (AMOC). Scientists warn that melting sea ice could reach a tipping point, causing circulation to release large amounts of fresh water into the North Atlantic.

If this happens, the AMOC could weaken or collapse, drastically changing weather patterns across the Northern Hemisphere, especially in Europe. New model projections suggest urgent emissions cuts are crucial to avert this dangerous shift.

The potential weakening of the AMOC (Atlantic Meridional Overturning Circulation) has become a major concern for climate scientists. However, as the system approaches a possible tipping point, its exact consequences and when they might occur remain uncertain.

To better understand these risks, University of Gothenburg climatologist Céline Heuzé teamed up with German researchers Marylou Athanase and Raphael Köhler to study the future of the Beaufort Gyre, the Arctic Ocean's main current. Located in the Beaufort Sea north of Alaska and Canada, this current plays a key role in the Arctic climate system.

Thinning Arctic sea ice may ultimately have an impact on the AMOC, and more research is needed to better understand the link between Arctic sea ice loss and the AMOC. Image credit: Alfred Wegener Institute/Stefan Hendricks

The Beaufort Gyre acts like a giant reservoir, storing and releasing fresh water. Its effects extend beyond the Arctic, affecting ocean conditions in the North Atlantic.

But rising temperatures in the Arctic are causing sea ice in the region to thin rapidly. Sea ice often acts as insulation, keeping the ocean cool. As sea ice disappears, more heat reaches the ocean surface, accelerating warming and causing further melting of the ice. Over the past two decades, the freshwater content of the Beaufort Sea has increased by 40%.

The Beaufort Gyre in the Arctic Ocean now holds large amounts of fresh water. If the circulation weakens due to climate change, it will release freshwater that could flood the North Atlantic and have an impact on the AMOC. Image source: Alfred Wegener Institute/Marylou Athanase

One of the key ocean circulation systems that climatologists monitor closely is the Atlantic Meridional Overturning Circulation (AMOC). This system includes the famous Gulf Stream, a vast network of currents in the Atlantic Ocean. It's driven by differences in water density: warm, salty water from the tropics flows north along the surface, cools when it reaches higher latitudes, becomes denser, and then sinks. These cooler, deeper waters then flow back south, creating a continuous loop that helps regulate climate throughout the Atlantic region.

Céline Heuzé of the University of Gothenburg is studying the role and vulnerability of the deep ocean to climate change, particularly the impact of its thinning sea ice cover. Photo credit: MalinArnesson

"The results of this study make us worry that the decrease in sea ice in the region could lead to a tipping point for AMOC collapse," said Céline Heuzé, senior lecturer in climatology at the University of Gothenburg and an expert in deep sea and sea ice.

In this study, the researchers used only global climate models that accurately represent the Beaufort circulation for their predictions. Climate models are computer simulations of Earth's climate system (atmosphere, oceans, land, and ice). Climate models are used to reconstruct past climate or predict future climate.

"Without urgent reductions in greenhouse gas emissions, this projection suggests that the Beaufort Gyre will weaken and release the fresh water it currently contains. This fresh water may then reach the North Atlantic and potentially have a negative impact on the AMOC," said Marylou Athanase, a researcher at the Alfred Wegener Institute in Germany and first author of the study.

The AMOC is part of the Gulf Stream, which is critical to Scandinavia's climate because it transports warm water to high latitudes in the Northern Hemisphere. The researchers now want to take a closer look at how the link between Arctic sea ice loss and AMOC weakening may develop in the future.

Compiled from /ScitechDaily