April 17, 2024

Climate Change Could Drop Atlantic Current In 2 Years

I The day after tomorrowthe planet’s warming causes the Atlantic meridional overturning circulation (AMOC), the formal name for the entire Atlantic Ocean current system, to effectively collapse — ushering in a new ice age on the planet.

The film’s writers may have taken dramatic liberties with climatology research to imagine such an outcome – after all, they had to find a reason for Dennis Quaid to make a perilous journey over a newly formed glacier around New York City to save Jake Gyllenhaal.

But it is not impossible to fall AMOC. In fact, we are fast approaching the end, thanks to climate change, according to a new study published Tuesday i Nature Communication predicted that it could collapse by the middle of the century, perhaps even as early as 2025.

“It requires immediate action,” Peter Ditlevsen, a climate researcher at the University of Copenhagen and co-author of the new study, told the Daily Beast. “With the worrying result, some research will be needed to deal with more climate model-based assessments of regional climate changes with the collapse of the AMOC.”

The ocean currents that make up the AMOC work like conveyor belts to transport warm water from the southern latitudes into the North Atlantic. Heat from the south leaves cooler and saltier water in the north (which is heavier) to sink. (The same type of salinity is lacking in the Pacific Ocean, which is why the water around Alaska is colder than in Scandinavia, even though they are at the same latitude.)

But AMOC can be shut down if too much fresh water is added to the ocean, reducing its salinity. Ocean waters become so heavy that the AMOC currents are essentially “off”. That freshwater infusion could come from melting ice sheets, increased river runoff, and increased precipitation—all things driven by climate change.

Ditlevsen and his co-author conducted their study by looking at North Atlantic sea surface temperature data going back to 1870, which can help tell us about the historical stability of the AMOC. After running new analyses, they concluded that AMOC is becoming more unstable over time. Mechanisms that maintain regularity are falling apart.

The authors’ analysis suggests that AMOC will collapse sometime between 2025 and 2095 – probably in the middle of the century, but they warn that it could happen sooner. This would likely lead to rapid rises in sea levels, and a sharp drop in temperature across the Northern Hemisphere. Severe storm events are likely to continue.

The new study is downright scary—if you buy its findings. And there are some doubts among other scientists. The latest report from the UN Intergovernmental Panel on Climate Change said AMOC collapse is unlikely based on current climate models. And New Scientist reports some other experts have warned that uncertainties make it difficult to predict when the AMOC tipping point will occur (which Ditlevsen himself conceded).

Still, the IPCC has been repeatedly criticized for pulling its punches and softening its conclusions in the face of political pressure. And most experts have noted that climate change has defied most past predictions.

The good news is that all of this is reversible—“if you respond to it quickly enough,” Ditlovsen said.

Once we cross the tipping point, it will be several years before the full AMOC collapse begins, at which point greenhouse gas concentrations can still be reduced to prevent worst-case scenarios.

That doesn’t mean there should be any reason not to act. “Will not be The day after tomorrowbut we don’t really have analogs for the fall, as it happened more than 12,000 years ago,” said Ditlevsen.

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