THE WORLD should brace for weather chaos due to the Atlantic Ocean’s circulation strength plunging to a “record low” because of climate change, warn s
THE WORLD should brace for weather chaos due to the Atlantic Ocean’s circulation strength plunging to a “record low” because of climate change, warn scientists.
The Atlantic’s flow – which is a key part of the Earth’s climate – has dropped in strength by 15 percent since the mid-20th century, boffs have concluded in a peer-reviewed study published in the journal Nature.
Intergovernmental Panel on Climate Change The global circulation system, pictured, is weakening and could lead to extreme weather across the globe, warn boffs
That’s a decrease of 3 million cubic meters of water per second, the equivalent of nearly 15 Amazon rivers.
The slowdown could kickstart severe weather cycles in Europe and across the world, and cause a rapid increase in sea levels on the US East Coast.
And if it continues at this rate, it may result in a complete circulation shutdown, which would be a catastrophic “tipping point”, warn researchers.
Such a scenario was the premise of the 2004 disaster movie The Day After Tomorrow.
“We know somewhere out there is a tipping point where this current system is likely to break down,” said study co-author Stefan Rahmstorf, a climate scientist at the Potsdam Institute for Climate Impact Research in Germany.
“We still don’t know how far away or close to this tipping point we might be. … This is uncharted territory.”
The Atlantic meridional overturning circulation (AMOC) is a critical conveyor belt for the earth’s climate.
It shifts warm, salty water from the tropics along the Gulf Stream off the US East Coast to the North Atlantic, where it cools, sinks and heads south.
Alamy A climate tipping point was central to the film The Day After Tomorrow
The faster it moves, the more water is turned over from warm surface to cool depths.
But the melting of Arctic sea ice and Greenland’s ice sheet due to global warming can interfere with this sinking process.
Recent research has confirmed that melted ice water is lingering on the ocean surface, where it could be disrupting the AMOC system.
The latest study highlights a curious pattern of ocean temperatures that match the impacts of weakening Atlantic currents – specifically a strong warming off the US East Coast paired with a cooling south of Greenland, which is sometimes dubbed the cold “blob”.
The boffs found that the odd alignment, which has resulted in regions of both record cold and warmth next to one another, has been developing since the 1950s, and matches what a high-resolution climate model predicted would take place.
Getty Images – Getty Scientists believe the shift in the Atlantic’s circulation may already be causing rising sea levels along the East Coast of the US
Another study in the same issue of Nature also found that the AMOC has slowed and is now weaker than at any time in more than a millennium.
This study meanwhile draws from sediment grains deposited by the deep-sea currents; the larger the grains, the stronger the current.
The researchers then used a range of methods to reconstruct near-surface ocean temperatures in regions where temperatures are impacted by AMOC strength.
That way they were able to determine that the weakening began around 160 or 170 years ago when the “Little Ice Age” in the Northern Hemisphere ended.
And that trend is thought to have continued to the present day.
“In terms of this initial drop in the AMOC, it’s very likely that’s a kind of natural process,” said Jon Robson, a researcher at the University of Reading and one of the study’s co-authors.
“It’s very likely, based on other evidence, that human activities may have continued to suppress the AMOC, or maybe led to further weakening.”
To avert a climate calamity, scientists are urging for an immediate reduction in the emissions of carbon dioxide.