Two studies bring bad news about the ocean currents at the center of the fictional (and scientifically inaccurate) climate change disaster movie “The Day After Tomorrow.”
Ocean currents are weakening due to climate change
Measurements of temperature, salinity and current in the Atlantic Ocean Current, taken by the University of Miami, show it has weakened by 10% over the past 20 years.
The potential disruption of major Atlantic currents due to anthropogenic climate change is back in the news.
It would be hard to think of a more frightening scenario than what is currently happening in the Atlantic Meridional Overturning Circulation (AMOC). AMOC states that the weakening and eventual collapse of the fickle Atlantic Current could change the climate and weather for hundreds of millions of people.
Two new scientific studies detail the current and potential future of the AMOC, the ocean current at the center of the fictional (and scientifically inaccurate) 2004 climate change disaster film The Day After Tomorrow.
In a study published April 8, scientists at the University of Miami determined that the AMOC has already weakened in four different locations in the Atlantic Ocean over the past 20 years. In another study published on April 16, a group of European scientists said the AMOC could weaken by 50% by 2100, eventually leading to “collapse.”
So what does this mean? And what is the difference between debilitation and collapse?
A weakening of the AMOC would mean that the ocean currents that control the Atlantic climate would slow for decades, while a collapse would mean that the entire current system would cross a tipping point and mostly come to a standstill, triggering sudden and potentially irreversible global climate disruption.
What is AMOC?
“The Atlantic Meridional Overturning Circulation is truly one of Earth’s key circulation systems,” said Niklas Boers of Germany’s Potsdam Institute for Climate Impact Research, author of a previous study on the subject.
AMOC is an important conveyor belt that transports seawater and air and influences the weather. Warm, salty water moves north from the tropics along the Gulf Stream off the east coast of the United States, reaches the North Atlantic Ocean, where it cools, sinks, and heads south.
The faster it moves, the more water moves from the warm surface to the colder depths.
This circulation keeps northern Europe several degrees warmer than normal and brings cooler water to the coasts of North America.
Previous studies in 2018 and 2021 also found that AMOC could collapse at some point this century.
Research results show that AMOC is weakening
An April 8 study by University of Miami scientists published in the peer-reviewed journal Science Advances found that the AMOC has weakened at four different latitudes across the western boundary of the North Atlantic over the past two decades.
“In some ways, observations on the western boundary, isolated from the eastern boundary, are the canary in the coal mine for AMOC trends,” study co-author Shane Elipot told USA TODAY in an email. “These findings support evidence of widespread weakening of AMOC.”
Meanwhile, an April 16 study by European scientists, also published in Science Advances, found that “most climate models underestimate the decline,” CNN reported. “The study shows that the AMOC is expected to slow by more than 50% by the end of the century, and its ‘significant weakening’ is 60% stronger than estimated by the average of all climate models.”
How close is AMOC to the ‘tipping point’?
“AMOC is probably heading towards a tipping point, which means that AMOC has entered a very weak state from which it cannot recover without significant effort. If the currently observed weakening continues at the same pace, AMOC could reach collapse in about 140 years. However, this weakening is likely to accelerate and occur sooner, highlighting the importance of continued monitoring of AMOC.”
How will the weakening of AMOC affect Earth’s weather and climate?
“A significant weakening of the AMOC would have implications for natural and human systems around the world, most notably leading to lower temperatures in the North Atlantic, increased winter storms in Europe, and reduced summer rainfall in the Sahel and South Asia,” Elipot told USA TODAY.
“Furthermore, if the AMOC weakens further, sea levels along the northeastern U.S. coastline are likely to rise even more rapidly than they are currently experiencing.”
What could be the reason for the weakening of AMOC?
In a podcast interview with USA TODAY, Elipot said the main reason for this decline is climate change. He said global warming would change the density of water, melt ice and cover the region with more fresh water, and reduce circulation, disrupting the normal sinking of the North Atlantic’s thick, cold water.
Elipot said mitigating climate change by reducing carbon emissions and transitioning to clean energy is important, along with continued monitoring and research to better predict and prepare for potential impacts.
