Climate Change Insights: How the AMOC May Endure Future Warming Challenges

New research indicates that the Atlantic Meridional Overturning Circulation (AMOC), a key system that transports heat to the North Atlantic and Northwestern Europe, is unlikely to collapse this century.

This study, published in Nature, was led by scientists from the Met Office and the University of Exeter. Dr. Jonathan Baker, the lead author, explains that the AMOC plays a vital role in our climate. Without it, temperatures in northwest Europe would be significantly cooler.

The research uses advanced modeling to show that the AMOC will withstand rising global temperatures and increased freshwater entering the North Atlantic. Instead, changes in the system are more influenced by winds over the Southern Ocean.

While a complete collapse of the AMOC within the next 75 years seems unlikely, the study warns that it is likely to weaken. This weakening could lead to climate challenges not just in Europe, but globally.

Professor Andrew Watson from the University of Exeter noted that the AMOC’s strength is influenced by conditions at both local and distant locations. The winds in the Southern Ocean help pull water from the deep ocean, which must then be balanced by water sinking in the North Atlantic.

Professor Rowan Sutton, Director of the Met Office Hadley Centre, pointed out that this research provides new insights into the AMOC’s resilience. While it suggests the system might be more robust than earlier studies indicated, it still reinforces the expectation of weakening over the 21st century. This change will have significant impacts on climate.

The findings align with the latest reports from the Intergovernmental Panel on Climate Change (IPCC), which suggests with medium confidence that the AMOC will not collapse suddenly this century. However, ongoing research is essential to understand its behavior better and to refine future predictions.

Professor Geoff Vallis from the University of Exeter highlighted that while an imminent collapse seems unlikely, it doesn’t mean we should ignore the serious challenges posed by global warming. He likened it to having insurance against a potential disaster, even if the risk seems low.

Under severe climate change scenarios, the study notes the potential emergence of the Pacific Meridional Overturning Circulation (PMOC) in the Pacific Ocean. However, this new system is not strong enough to counterbalance the changes driven by the Southern Ocean winds. Therefore, some degree of sinking in the North Atlantic is necessary to prevent a complete AMOC breakdown.