Scientists detect alarming Atlantic signal as crucial ocean current nears tipping point

Climate researchers are increasingly focused on an unusual patch of chilly water near Greenland, saying it may signal that one of the planet's key ocean current systems is losing strength and edging toward a dangerous threshold.

What happened?

According to Futurism, citing a New Scientist report, researchers are paying increasing attention to a growing "cold blob" in the North Atlantic near Greenland, where surface waters are cooling even as much of the planet continues to warm.

At the center of the anomaly is the Atlantic Meridional Overturning Circulation, or AMOC, the vast Atlantic current network that redistributes heat around the world.

New Scientist reported that mounting evidence suggests the AMOC is slowing. As that happens, cold waters from the Greenland ice sheet can accumulate in the North Atlantic instead of circulating through the system.

Deep-ocean buoy data have detected slower flow in important Atlantic currents at several locations, adding to worries that the larger system is weakening.

Why does it matter?

Because the AMOC helps shape weather in North America and Europe, further weakening could alter jet streams and intensify extreme weather conditions in ways that reach far beyond the ocean.

As Penn State assistant professor Laifang Li said in a press release about an earlier AMOC study, "the cold blob can disturb the atmospheric jet stream and storm activities, so it has implications for extreme weather events in North America and Europe," Futurism noted.

The consequences could be greater if the system deteriorates much further. A complete AMOC collapse would represent a climate tipping point and, by around 2040, could leave some areas of the globe much colder and others much drier.

What are people saying?

Scientists are still debating exactly what is driving the cold blob. Li is among the researchers who point to atmospheric forces, while others believe the evidence indicates changes in the ocean itself.

Stefan Rahmstorf, who works at the Potsdam Institute for Climate Impact Research, is firmly in that second camp. He told New Scientist, after his team found evidence that the heat loss from the ocean surface has been shrinking since 1955, that, "even if, in some modelling approaches, it seems possible that the cold blob is caused by the atmosphere, in fact, the data show it is caused by the ocean."

Get TCD's free newsletters for easy tips, smart advice, and a chance to earn $5,000 toward home upgrades. To see more stories like this one, change your Google preferences here.