Europe faces 'little Ice Age' as key North Atlantic current on the brink of collapse

Climate change is weakening a key ocean current to the point of collapse, according to a new study. As shell layers provide an annual record of ocean conditions, scientists were able to study records of quahog clams, which can live for over 500 years, and dog cockles.

They studied these natural archives to understand long-term patterns in Atlantic Ocean currents. According to the new study, led by the University of Exeter, the North Atlantic Subpolar Gyre, a system of rotating ocean currents south of Greenland, is now reaching a "tipping point". It has been losing stability since the 1950s, but now, it is close to passing a critical threshold, which could cause dramatic climate changes.

The North Atlantic Subpolar Gyre moves heat from the tropics to the North Atlantic, and it is a part of a much larger network of ocean currents called the Atlantic Meridional Overturning Circulation (AMOC). This helps with regulating temperatures in Europe and North America.

But as this movement slows down, it could plunge Europe into another 'Little Ice Age', a period of cooler global temperatures that had massive effects on climate, agriculture, and societies, particularly in the Northern Hemisphere. During the last Little Ice Age, commonly dated to between 1300 to 1850, rivers froze over and crops were decimated when average temperatures dropped by about 3.6°F (2°C).

The author of the study, Dr Beatriz Arellano Nava, a lecturer in physical oceanography at the University of Exeter, called the findings "highly worrying".

She said: "Our results provide independent evidence that the North Atlantic has lost stability, suggesting that a tipping point could be approaching, although it remains uncertain when this threshold might be reached.

"We still need to understand more of the impacts of a subpolar gyre abrupt weakening. But what we know so far, with the few studies that have been published, is that it would bring more extreme weather events, particularly in Europe ... and also changes in global precipitation patterns."

As climate change makes conditions different now than they were in the 13th century, scientists don't know if another Little Ice Age is possible, Arellano Nava said. Nonetheless, it illustrates some of the climate impacts that could be coming our way, including harsher winters and more intense storms.