Atlantic 'Cold Blob' and Antarctic Sea‑Ice Decline Raise Ocean‑Circulation Alarm

Scientists have identified a persistent patch of unusually cold water south of Greenland, known as the Atlantic “cold blob,” as evidence that the Atlantic Meridional Overturning Circulation (AMOC) is weakening. The new study links the cooling to reduced northward transport of warm tropical waters, a process that could lead to regional climate disruptions in Europe and the U.S. East Coast and affect marine ecosystems and food supplies if the AMOC were to collapse.

Separate research shows that Antarctic sea‑ice growth halted after 2015 as the Southern Ocean warmed, bringing salty deep water toward the surface. Stronger winds and increased surface heat have accelerated melt in East Antarctica, creating a feedback that may sustain a prolonged low‑ice state and destabilize global ocean‑current systems. Both findings highlight the risk of tipping points in the world’s major ocean circulations.