The Atlantic's ‘Cold Blob' Could Change Weather Across America
The mysterious North Atlantic “cold blob”-an unusually cool patch of ocean south of Greenland-may be more than a climate oddity. New research suggests it could be a sign that a major Atlantic current system is weakening, a shift that could eventually affect weather patterns and coastal flooding in parts of the United States.
The “cold blob,” also known as the “warming hole,” is an area of unusually cold water in the North Atlantic south-east of Greenland. It has puzzled scientists for years because it has stayed cool while much of the world’s oceans have continued to warm.
A study published in May in Geophysical Research Letters found that the cold blob is most likely being caused by a weakening Atlantic Meridional Overturning Circulation (AMOC), a major system of ocean currents that helps move heat around the Atlantic.
Changes in the AMOC could have effects far beyond the North Atlantic, potentially influencing sea levels, rainfall and storm systems that affect parts of the United States.
What Could a Weakening AMOC Mean for America?
The AMOC is often described as a giant ocean conveyor belt, according to the science magazine New Scientist. It carries warm, salty water north through the Atlantic before colder, denser water sinks and flows back south deep below the ocean surface. This process helps regulate temperatures and weather across the Atlantic region.
Scientists have long warned that climate change could weaken the system. As Greenland’s ice melts, large amounts of freshwater flow into the North Atlantic. Because freshwater is less dense than salty water, it becomes harder for the current to complete the sinking process that helps keep the circulation moving.
While much of the discussion around a weakening AMOC has focused on Europe, researchers say the effects could also be felt in the United States.
One of the biggest concerns is rising sea levels along the East Coast. A study reported by Live Science last year found that a slowdown in Atlantic circulation contributed significantly to increased coastal flooding risk along the U.S. Northeast coast since 2005, with researchers estimating that AMOC weakening may account for 20 to 50 percent of the increase in flood days.
Other studies have also linked a weaker AMOC to changes in weather patterns that could affect North America. A 2024 study published as a preprint on arXiv found that a declining AMOC could shift rainfall patterns across the tropical Atlantic, while broader assessments by the Intergovernmental Panel on Climate Change (IPCC) concluded that a weaker AMOC is likely to influence storm tracks and rainfall patterns around the North Atlantic region.
According to the IPCC’s Sixth Assessment Report, published in 2021, changes in the AMOC can affect large-scale weather patterns, potentially influencing rainfall and storms across parts of eastern North America. However, researchers cautioned that the exact impacts on individual regions of the United States remain uncertain.
The new Geophysical Research Letters study does not suggest that an AMOC collapse is imminent. However, its authors argue that the persistence of the North Atlantic cold blob is best explained by changes in ocean circulation rather than changes in winds or cloud cover, adding to growing evidence that the current system may already be weakening.
2026 NEWSWEEK DIGITAL LLC.
This story was originally published June 8, 2026 at 11:32 AM.