An international group of scientists has concluded that the famous "cold blob" in the North Atlantic, south of Greenland, is mainly caused by a weakening of the Atlantic Meridional Overturning Circulation (AMOC) — one of the key systems regulating the planet's climate. The study results are published in the journal Geophysical Research Letters.

What the "cold blob" is

This is an anomalously cold area of the ocean that has stood out against the backdrop of general warming for several decades. Previously, it was primarily associated with enhanced heat loss from the ocean surface, but the new analysis reveals a different picture.

Main cause — weakening of AMOC

AMOC works like a massive oceanic conveyor belt: it transports warm surface waters from the tropics northward and returns cold deep waters back south. This circulation is largely responsible for the relatively mild climate of Europe and the eastern coast of North America.

According to new calculations, AMOC could weaken by 51% by 2100 — 60% more than previous models predicted. The earliest possible collapse of the system, according to estimates, could occur as soon as 2026, while the median scenario under high emissions is 2063.

The main factor in the weakening is the intense melting of the Greenland ice sheet. Fresh water dilutes the salty waters of the North Atlantic, disrupting the density gradient that drives the entire circulation.

Possible consequences

In the event of serious weakening or collapse of AMOC, Europe's climate could change dramatically:

  • Cooling of 5–10 °C over several decades
  • Changes in precipitation patterns
  • Sea level rise in certain regions
  • Weakening of tropical monsoons, on which agriculture and food security depend for billions of people in Asia and Africa

In brief

Scientists have linked the existence of the "cold blob" in the Atlantic to the progressive weakening of the Atlantic Meridional Overturning Circulation (AMOC). According to new forecasts, the system could weaken by 51% by 2100, and in the worst-case scenario, collapse could occur as early as the coming years. This threatens serious climate changes in Europe and other regions of the planet. The study's authors call for including AMOC status among the key global climate indicators, alongside temperature and CO₂ levels.