Key weakening of the Atlantic Current, but could it collapse completely?

Two days later is often invoked in climate talk, but then we keep having extreme events that seem to mimic the movie. The last example is a new to study, published Thursday in Nature Climate Change, which sounds the alarm on “early warning signals” Atlantic southern overturning circulation could collapse.

Known as AMOC by scientists, it is a crucial global current that scientists have worried about for years. The new document suggests that climate change has fundamentally jeopardized the stability of AMOC and that the system is now at “a point near a critical transition”. It’s not the only concern when it comes to climate change—have you looked out the window lately?– but its collapse has serious implications for the world.

At first glance, a change in the speed of an ocean current does not seem this disturbing. After all, we are facing rampant fires, flooding, heat, and sea level surges around the world. Can’t ocean currents stay a bit while we try to figure out the rest of our shit? But AMOC is actually critically important to weather around the world. It helps carry warm water from the tropics to the North Atlantic, which keeps Europe temperate for its latitude and also ensures that the weather around the world remains normal.

AMOC is so important, in fact, that its well-being is seen as a key “tipping point” for the climate. Scientists have been keeping an eye on AMOC because, worryingly, it appears that climate change is having an unwanted impact. Greenland the ice cap is melting, resulting in a large pool of cold fresh water in the North Atlantic which essentially acts as an informed roadblock.

This is what makes this new study so disturbing. AMOC’s previous studies have relied heavily on data from the last decades. The new study analyzes historical temperature and salinity data dating back to the 19th century as well as the most recent climate data and models. Together, they all suggest that AMOC is losing strength and is more sensitive to major changes that could take it off course.

So … what is there for the common people to take in here? Do we have to prepare for the ocean’s conveyor belt to suddenly stop and change the weather as we know it throughout our lifetimes? Will Dennis Quaid guide us all through the New York Public Library to save us from a monstrous storm surge wave?

The article includes absolutely no predictions for when AMOC could go wrong, but it suggests that the current is losing strength to resist any major change. According to the latest climate models, a collapse of AMOC by 2100 is quite unlikely, not impossible, but it is unlikely to happen.

“Yes, a collapse could occur in our lifetime, but it is impossible to give a probability because our models are not good enough to trust their future projections in a quantitative sense”, Sybren Drijfhout, oceanographer at the University of Southampton and affiliated with the Royal Netherlands Meteorological Institute who studied AMOC, said in an email. He also noted that “previous media reports and, to a lesser extent, the manuscript itself, tend to make overly strong statements and tend to overlook various caveats that should have been made.”

Among the issues he noted, the paper examines AMOC’s ‘fingerprints’ and not the circulation itself, fingerprints that could reflect changes in other parts of the climate system such as the oscillation. North Atlantic. He added that while the signals examined by the newspaper appear to correspond to the collapse of AMOC, they do not necessarily “predict such a collapse.”

In addition, the prospect of crossing this threshold of “changeover” of the AMOC is not like disastrous than reaching other tipping points, because the slowdown in the ocean’s circulatory system unfolds over decades, not years. In other words, even if we pass the first point of no return, there is theoretically time to fix it by bringing temperatures under control before it collapses completely. Other recent research shows that the planet would need to warm by about 7.2 degrees Fahrenheit (4 degrees Celsius) for AMOC to cross the tipping point threshold, but it could theoretically return.

“If we were to cross the tipping point threshold of AMOC, there is always the possibility with rapid climate mitigation that a complete collapse could still be avoided,” Paul Ritchie, post-doctoral fellow at the University of Exeter, who studies tipping points and led this other research, said in an email. With that in mind, there are other more pressing climate issues that can occupy our anxious minds.

Ritchie said he was more worried about reaching crisis points in other systems that “operate on much faster time scales.” Another paper released last year shows that some key ecosystems we rely on, like the Amazon, could suddenly collapse in the coming decades if we continue to push them too hard through the climate crisis and deforestation.

“Some tilting elements operate on much faster time scales, like the monsoons and the Amazon rainforest, which can last for decades or just years, and for those faster tilting elements there is less chance of prevent irreversible change once the threshold is crossed, “said Ritchie. “So maybe I’m more concerned about crossing a rapid tipping point, like the Amazon rainforest, because there would be little chance of preventing large-scale dieback (which would further amplify global warming) if we had to cross that threshold. particular threshold.

But that doesn’t mean we shouldn’t at least think about what would happen if AMOC collapsed. Drijfhout said the new study is a “very interesting and disturbing article for society with an important message that calls for further research to corroborate these still preliminary results.”

“The consequences of a collapse would be significant, so we should always be concerned about it, even though the likelihood might be low,” Ritchie said. “I see it similar to the risk of a house fire: the probability is very low, but we still install smoke detectors to keep us safe. “

Frankly, when it comes to our current climate, the alarms are already ringing loud enough. We no longer need warnings to know that the use of fossil fuels must be reduced.