A mysterious ‘cold blob’ in the ocean has puzzled scientists. A new study says it’s an ominous sign | CNN

In the North Atlantic Ocean, south of Greenland and Iceland, a large patch of water is doing something very strange. While the rest of the ocean heats up, it’s been getting colder. A new study says it has the answer to this mystery — and it’s an ominous sign the world is hurtling toward one of the most alarming climate tipping points. The swath of ocean — dubbed the “cold blob” or “warming hole” — has cooled by nearly 1 degree Celsius (1.8 Fahrenheit) since 1900. Scientists have long debated whether this anomaly is driven by heat loss from the ocean surface due to changes to winds and clouds, or whether it’s a signal of the weakening of a critical system of ocean currents, which transports heat. The new research concludes it’s the latter, and the finding points to a worrying future. ☔️ ☀️ Explore CNN Weather for iPhone The Atlantic Meridional Overturning Circulation, or AMOC, works like a vast ocean conveyor belt, pulling warm water from the tropics to the Northern Hemisphere, where it cools, sinks and flows back south. A raft of research suggests this system is weakening as human-driven global warming melts ice and causes a surge of freshwater into th

Jun 12, 2026 → Jun 18, 2026