World near climate tipping point? Why Atlantic 'cold blob' is bad news
A new study examines the only region on Earth that has cooled, not warmed, in recent years. Scientists say the 'cold blob' is mainly tied to the Atlantic Meridional Overturning Circulation (AMOC).
By Kirsten Ripper & Euronews with AP
Published on 16/06/2026 - 17:33 GMT+2
In the North Atlantic south of Greenland lies the so‑called "cold blob", a mysterious patch of cold that is considered the only place on Earth where it has actually become colder over recent decades.
A team led by Prof Dr Stefan Rahmstorf from the Potsdam Institute for Climate Impact Research (PIK) has now published a new study on the "warming hole" in the Atlantic Ocean in Geophysical Research Letters (source in German).
Analysing temperature data sets based on measurements in the North Atlantic, the research team concludes that it is above all changing heat transport in the ocean that is causing the cold blob.
The scientists write: "This is a cause for concern, as any further weakening of Atlantic heat transport in the course of future climate change could have severe impacts on climate and weather conditions in Europe and other parts of the world."
In February, the Nordic Council – whose members are Denmark, Iceland, Norway, Sweden and Finland, with Åland, the Faroe Islands and Greenland as associate members – warned that winter temperatures in Iceland could fall to as low as minus 45 degrees Celsius. The island would then be completely encased in ice, for the first time since the Viking Age.
Why AMOC is so important
The weakening of the so‑called AMOC has long been a cause of concern for climate scientists. AMOC stands for "Atlantic Meridional Overturning Circulation", a vast system of ocean currents. It carries warm water northwards along the surface of the Atlantic and cold water southwards along the seabed. It is one of the most important systems distributing heat around the planet.
"Our analysis supports the interpretation of the observed cold blob as a sign of a weakening AMOC, which makes a major contribution to lateral heat transport in this subpolar gyre region," the new study from the Potsdam Institute for Climate Impact Research states.
Previous research into past episodes of dramatic cooling in Europe over the last 100,000 years suggests that melting ice sheets could weaken the AMOC by changing the salinity and temperature of seawater.
Freshwater reduces salinity – and thus the density of the water – at the ocean surface. That means less surface water sinks, which could slow down the current.
Is the world approaching the tipping point?
For years, research teams have been trying to determine when the tipping point of the Atlantic Meridional Overturning Circulation (AMOC) might be reached, a shift that, in the midst of global warming, could trigger dramatically cold winters in northern Europe.
In the event of an AMOC collapse, sea levels along the US east coast would rise rapidly, because the current normally pushes water away from the land. Storms in the Atlantic would increase in intensity. But for now, forecasts remain difficult.
Around 12,500 years ago, during the last cold period, or Younger Dryas, it took about 100 years for the AMOC to become fully functional again. Temperatures in Greenland then needed around 40 years to recover from the extreme glacial conditions.
The authors of the latest study speak of "early warning signals" that ocean circulation is approaching a tipping point, as well as of "clear evidence of a weakening AMOC". And they write that "this risk requires urgent attention from policymakers".
