Is the Mysterious "Cold Spot" in the North Atlantic an Omen?

According to a CNN (Japanese version) article published on June 13th, a strange phenomenon is taking place across a vast region of the North Atlantic south of Greenland and Iceland. While most ocean areas are warming, this particular region is actually cooling.

A new study provides an answer to this mystery, indicating it is a troubling sign—one that sounds the alarm about the world approaching one of the most alarming tipping points in climate change.

Scientists have long debated whether this anomaly results from changes in wind and clouds leading to heat loss from the sea surface, or if it signals a weakening of crucial oceanic heat-transport systems. The new research concludes the latter, raising concerns for the future.

The Atlantic Meridional Overturning Circulation (AMOC) is a major Atlantic current system, functioning like a massive ocean conveyor belt. Through this circulation, warm water from the tropics moves toward the Northern Hemisphere, cools down, sinks, and then flows back southward.

As numerous studies have shown, AMOC’s function is currently weakening. Global warming caused by human activities is driving ice melt. The influx of large amounts of freshwater into the ocean disrupts the AMOC mechanism, which relies on a delicate balance between heat and salinity.

Some scientists warn that AMOC is nearing a critical threshold—a collapse could occur within this century, and if it happens, it would be inevitable.

The end of AMOC would trigger global catastrophe. Sea levels along the U.S. East Coast are accelerating upward. Winters in Europe could face severe cold waves, African monsoon patterns may shift, causing prolonged droughts.

Some researchers interpret these "cold spots" as traces of changes in AMOC—precisely because AMOC transports significant heat through that region.

To better understand what's happening in this part of the Atlantic, scientists combined actual ocean heat data collected from instruments and satellites with climate models.

The study found that cooling at the cold spot occurs not only at the sea surface but also in the deep ocean—where atmospheric influences such as wind and clouds are far weaker.

The findings show clear evidence pointing to AMOC's influence. Professor Stefan Rahmstorf, a physicist and oceanographer at the University of Potsdam and one of the authors of the research paper, stated: “AMOC is changing ocean heat transport,” which leads to the cooling observed in the cold spot.

He further added that there is substantial evidence showing AMOC is weakening, with its function now at its lowest level in approximately the last 1,000 years.

René van Westen, an ocean and atmosphere researcher at Utrecht University who did not participate in the study, noted that previous research had clearly indicated cold spots can form even under atmospheric conditions. However, the consistency of results across different datasets in the new study “strengthens the accuracy of this conclusion.”

Meanwhile, David Sone, professor of ocean and climate science at University College London (UCL), who was not involved in the study, pointed out that real-world data remains limited. He cautioned that available data should not be considered a complete replication of reality.

Sone told CNN that uncertainty still exists, stating: “I don’t think this study will serve as the final word on the issue.”

Jonathan Bamber, senior climate scientist at the UK Met Office, agrees. He told CNN: “I’d prefer to view this study as additional evidence of AMOC’s contribution to the cold region. I don’t believe it fully resolves the mystery.”

Original: toutiao.com/article/1867890150867977/

Disclaimer: The views expressed in this article are those of the author(s) alone.