The collapse of a crucial network of Atlantic Ocean currents could push parts of the world into a deep freeze, with winter temperatures plunging to around minus 55 degrees Fahrenheit in some cities, bringing “profound climate and societal impacts,” according to a new study.
There is increasing concern about the future of the Atlantic Meridional Overturning Circulation — known as the AMOC — a system of currents that works like a giant conveyor belt, pulling warm water from the Southern Hemisphere and tropics to the Northern Hemisphere, where it cools, sinks and flows back south.
Multiple studies suggest the AMOC is weakening with some projecting it could even collapse this century as global warming disrupts the balance of heat and salinity that keeps it moving. This would usher in huge global weather and climate shifts — including plunging temperatures in Europe, which relies on the AMOC for its mild climate.
“What if the AMOC collapses and we have climate change? Does the cooling win or does the warming win?” asked René van Westen, a marine and atmospheric researcher at Utrecht University in the Netherlands and co-author of the paper published Wednesday in the Geophysical Research Letters journal.
This new study is the first to use a modern, complex climate model to answer the question, he told CNN.
The researchers looked at a scenario where the AMOC weakens by 80% and the Earth is around 2 degrees Celsius warmer than the period before humans began burning large amounts of fossil fuels. The planet is currently at 1.2 degrees of warming.
They focused on what would happen as the climate stabilized post-collapse, multiple decades into the future.
Even in this hotter world, they found “substantial cooling” over Europe with sharp drops in average winter temperatures and more intense cold extremes — a very different picture than the United States, where the study found temperatures would continue to increase even with an AMOC collapse.
Sea ice would spread southward as far as Scandinavia, parts of the United Kingdom and the Netherlands, the research found. This would have a huge impact on cold extremes as the white surface of the ice reflects the sun’s energy back into space, amplifying cooling.
The scientists have created an interactive map to visualize the impacts of an AMOC collapse across the globe.
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