The Atlantic Meridional Overturning Circulation (AMOC) is a pivotal component of the North Atlantic Ocean circulation and global thermohaline circulation and is commonly referred to as the global thermohaline conveyor belt. Ocean currents are essential for regulating Earth’s climate through the AMOC, which transports warm, salty water northward in its upper arm and returns colder and fresher water southward in the deep ocean. This circulation relies on deepwater formation in the high-latitude North Atlantic sinking as it cools and becomes denser. However, scientists are concerned that the higher presence of surface freshwater can slow the AMOC by inhibiting this cycle.
Dan Seidov, Alexey Mishonov, and James Reagan, researchers from NOAA and UMD/ESSIC, conducted a comprehensive review of oceanographic data and climate models related to the AMOC’s role in Earth’s climate and ocean circulation. They analyzed numerous published studies to offer a clearer understanding of the decadal changes in the AMOC and the variability of the North Atlantic’s circulation and climate. By examining significant research outcomes, they aimed to provide new insights into both model and observational analyses, as well as paleoceanographic reconstructions, with the goal of enhancing the understanding of AMOC variability and presenting a unified perspective on potential future climate change predictions in the North Atlantic.
The authors contend that certain factors, such as wind stress, might counterbalance the increase in freshwater and stabilize the AMOC. It is an undisputed fact that the AMOC has been slowing down over the past few decades. However, despite this deceleration and the possibility of further slowing or changes, the authors conclude that, based on the majority of research on the AMOC, its robustness—particularly within the Gulf Stream system, which constitutes a major part of the upper arm of the AMOC—suggests that a complete collapse of the AMOC is unlikely in the near future. Nonetheless, some unpredictable changes in the AMOC may still occur and cannot be ignored. Closer monitoring and modeling with improved resolution and surface climatology data are needed to enhance understanding and predicting the future of the AMOC in the long run.
Alexey Mishonov, a co-author of this publication, is a Research Scientist at UMD/ESSIC with extensive expertise in various oceanography fields, including ocean color, water transmissivity, particulate organic carbon study, oceanographic data management, analysis, and climate research.
To access the paper, click here: “AMOC and North Atlantic Ocean Decadal Variability: A Review”.
