The latest study on Earth’s ocean currents, particularly considering the Atlantic Meridional Overturning Circulation (AMOC), reconfirms the concerns raised by a study done previously that indicated that the system is on a path toward collapse.
This has profound implications for global climate patterns and poses significant challenges for society. The research, led by René van Westen and his team at Utrecht University, introduces an early warning system based on observable changes in salinity transport at the southern boundary of the Atlantic Ocean.
“The temperature, sea level and precipitation changes will severely affect society, and the climate shifts are unstoppable on human time scales,” the authors of the latest study warn in an article for The Conversation.
AMOC plays a very crucial role in redistributing heat around the planet. They do this by transporting warm water northward and cold water southward. However, it has been slowing down since the mid-1900s due to factors such as increased freshwater input from melting glaciers and greater precipitation, which reduce seawater salinity. This decrease in salinity disrupts the sinking process of dense, cold water, weakening the circulation system.
“We were able to develop a physics-based and observable early warning signal involving the salinity transport at the southern boundary of the Atlantic Ocean,” Van Westen and team explain.
The study suggests that a tipping point for AMOC collapse may be reached within the next few decades, as indicated by a slowdown in salinity decline at the southern boundary of the Atlantic. While direct monitoring of AMOC began relatively recently in 2004, indirect indicators like salinity levels provide valuable insights into its behavior.
Importantly, the research underscores the sensitivity of AMOC to changes in environmental conditions, highlighting a potential underestimation of its stability in current climate models. This discrepancy raises concerns about the accuracy of predictions regarding AMOC collapse and its cascading effects on global climate systems.
Historical data suggests that AMOC collapse occurs cyclically over million-year scales, with significant consequences such as the southward extension of the Arctic and disruptions to regional climates, including cooling in northwestern Europe and alterations to tropical monsoons.
The consequences of AMOC collapse extend way and far beyond climate dynamics to encompass entire ecosystems and global food security. Stefan Rahmstorf, a climatologist at Potsdam University, has greatly emphasized the urgency of addressing the looming threat which is a warning that if ignored could have very serious consequences.
In summary, the latest study reinforces fears of an impending collapse of AMOC and emphasizes the need for proactive measures to mitigate its potentially catastrophic impacts. By providing an early warning system, the research offers valuable insights into the complex dynamics of Earth’s ocean currents, underscoring the interconnectedness of global climate systems and the urgency of addressing climate change.