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The North Atlantic’s ‘cold blob’ may signal a major current’s decline

The Atlantic Meridional Overturning Circulation may be near a tipping point, researchers say

A simulation of ocean temperatures from 1993 to 2021, showing a "cold blob" of water south of Greenland that has cooled in that time relative to the rest of the ocean.

A patch of ocean just south of Greenland and Iceland has gotten colder (shown in dark blue) from 1993 to 2021 even as the rest of Earth's oceans have warmed (yellow to dark red). The map shows how fast each part of the ocean is warming or cooling compared with the global average.

S. Rahmstorf et al/Geophysical Research Letters 2026

By Carolyn Gramling

Earth’s oceans are heating up, but one patch in the North Atlantic has cooled by about 1 degree Celsius since the 19th century.