North Atlantic Cold Blob Cools Nearly 1C Since 1900 as AMOC Slowdown Raises Collapse Fears
Updated
Updated · The Independent · Jul 7
North Atlantic Cold Blob Cools Nearly 1C Since 1900 as AMOC Slowdown Raises Collapse Fears
1 articles · Updated · The Independent · Jul 7
Summary
A giant cold patch south of Greenland has cooled by nearly 1C since 1900, making the subpolar North Atlantic the only region to show significant long-term cooling since the 19th century.
A May study in Geophysical Research Letters linked that “cold blob” mainly to weaker ocean heat transport in the AMOC, with Greenland meltwater freshening surface waters and disrupting the sinking that helps drive the circulation.
That cooling can reshape the jet stream, with researchers tying it to more extreme European summer heatwaves in the near term even as a weaker AMOC could eventually leave northern Europe with a climate more like eastern Canada.
Direct AMOC observations cover only 25 to 30 years—well short of the roughly 60 years scientists say are needed—so the extent of any current weakening remains disputed despite climate models broadly projecting decline this century.
Scientists are split over how close the AMOC may be to collapse, but warn the high-risk scenario could intensify heatwaves, raise North Atlantic sea levels, disrupt marine food chains and reduce the ocean’s ability to store CO2.
Could a failing Atlantic current bring a deep freeze to Europe while fueling extreme global heatwaves?
Is the Atlantic's vital ocean current collapsing decades sooner than scientists previously warned?
As warnings of an ocean tipping point intensify, why is the crucial monitoring system facing budget cuts?
Approaching the AMOC Tipping Point: The North Atlantic Cold Blob and the Future of Global Climate Stability
Overview
The North Atlantic's 'Cold Blob'—a region of unusually cool sea surface temperatures—signals important changes in the Atlantic Meridional Overturning Circulation (AMOC). Human-driven global warming causes rising temperatures, which accelerate the melting of ice sheets and glaciers. This melting releases large amounts of freshwater into the ocean, disrupting the balance of heat and salinity that keeps the AMOC moving. As a result, the AMOC weakens, slowing its normal circulation. This chain of events not only explains the appearance of the Cold Blob but also highlights the risk of major climate shifts if the AMOC continues to decline.