Scientists warn that a potential collapse of the Atlantic Meridional Overturning Circulation (AMOC) could have severe consequences for global climate, ecosystems, and human societies. The AMOC, a major component of the Earth’s ocean circulation system, plays a critical role in regulating climate by transporting warm water from the tropics to the North Atlantic and sinking cold water to the deep ocean, a process that also helps remove significant amounts of carbon dioxide from the atmosphere.

Experts agree that while a sudden collapse of the AMOC remains a low-probability event, its impacts would be disruptive and far-reaching. According to the latest assessment by the Intergovernmental Panel on Climate Change (IPCC), the collapse is considered a high-risk scenario, though the timing and likelihood remain uncertain. Scientists emphasize that such an event would trigger rapid shifts in regional climates, including intensified heat waves and abrupt sea level changes along the North Atlantic coastlines.

Biological oceanographer Helen Findlay from Plymouth Marine Laboratory highlighted the ripple effects that an AMOC collapse could have on marine ecosystems. She noted that significant changes in plankton populations—the base of the marine food web—could undermine fish stocks and affect seabirds and marine mammals. This, in turn, would threaten the livelihoods of coastal communities that depend on fisheries, potentially leading to economic instability or fishery collapses.

The AMOC also plays a pivotal role in mitigating climate change by transferring carbon dioxide from the surface to the deep ocean, where it can be stored for millennia. A slowdown or collapse would reduce this natural carbon sink, allowing more greenhouse gases to accumulate in the atmosphere and accelerating climate warming.

Melting polar ice caps, particularly in Greenland, are a key factor contributing to the weakening of this circulation system, as freshwater influx disrupts the sinking of dense, salty water in the North Atlantic. While there is some scientific debate regarding how close the system is to a full collapse, there is widespread agreement that the potential consequences warrant urgent attention.

Researcher Lehner emphasized the severity of the situation, stating that the possibility of collapse presents risks too great to ignore. The only currently known way to prevent such an outcome is to reduce greenhouse gas emissions significantly.

Findlay echoed this sentiment, warning that waiting for absolute certainty could mean crossing a point of no return. She urged policymakers and the public to heed the signals from the ocean and take decisive action to mitigate climate risks while there is still an opportunity to do so.