The Atlantic Meridional Overturning Circulation (AMOC), also known as the “Ocean Current,” plays a crucial role in regulating Earth’s climate by transporting heat from the Southern to the Northern Hemisphere. Climate models have long predicted that global warming will cause the AMOC to weaken, with some projecting substantial weakening amounting to a near-collapse relative to its current strength. However, a new study from Caltech has found that this weakening may be less severe than previously thought.
Researchers used a simplified physical model based on fundamental principles of ocean circulation and incorporated real-world measurements of the ocean current’s strength collected over 20 years. The results indicate that the AMOC will weaken by around 18 to 43 percent at the end of the 21st century, which is less than the substantial weakening predicted by some climate models.
The study’s findings suggest that much of the previous uncertainty and extreme AMOC weakening projections were due to biases in how climate models simulate the ocean’s current state. The researchers found that a stronger present-day AMOC tends to project greater weakening under climate change because it allows changes in surface water temperature and salinity properties to penetrate deeper into the ocean.
This new understanding significantly narrows the range of future AMOC weakening, addressing a long-standing uncertainty in climate science. The study’s lead author, Dave Bonan, emphasized the need for higher-resolution climate models that include more sophisticated processes to provide deeper insights into AMOC behavior and improve projections of its future changes.
Source: https://www.caltech.edu/about/news/atlantic-ocean-current-expected-to-undergo-limited-weakening-with-climate-change