Study warns of Atlantic current collapse: The resulting scenario is grim

The large system of ocean currents is one of the benchmarks that scientists use in determining the planet's "tipping point" when it comes to climate, and its collapse could signal more dangers to humanity.

Since the major drought of 2000, several more dry spells have occurred in India, accounting for 60 percent of all recorded water shortages in the country. (File: Rick Wilking RTW/CN via Reuters)
Others

Since the major drought of 2000, several more dry spells have occurred in India, accounting for 60 percent of all recorded water shortages in the country. (File: Rick Wilking RTW/CN via Reuters)

In the summer of 2000, a deadly drought swept through India. Low rainfall in two previous years led to the calamity, killing hundreds of people and severely affecting at least 130 million others.

It was the worst dry spell the country had faced in 100 years. Since then, several more droughts have taken place, accounting for 60 percent of all recorded water shortages in the country.

Around the same time that year, in another part of the globe, the US state of North Carolina's Triangle area reported a severe snowstorm, producing the most amount of snow in 22 years.

The so-called Carolina Crusher forced some of the southern US cities to shut down for days. Similar severe blizzards would follow, including Chicago's "Snowmageddon" of 2011 and the 2019 polar vortex that affected the US Midwest.

Both countries as well as other parts of the world, including South America, West Africa and Europe could experience similar extreme scenarios in the not-so-distant future, and most likely in greater frequencies, should a major Atlantic current collapse by the middle of this century due to global heating, according to a new study published in the journal Nature Communications.

The scientific analysis of changes in sea currents also warned that the collapse could even occur as early as 2025 or as late as 2095, resulting in disastrous consequences worldwide if carbon emissions are not reduced.

For instance, rain patterns that billions of people depend on for agriculture in India, South America and West Africa could be disrupted, resulting in droughts. Although droughts can also be caused by rising temperatures, deforestation and higher demands due to increasing in population, the supply itself could be disrupted due to changing weather patterns.

About half of the world's 7.8 billion population already lives in water-scarce regions, and more droughts could have devastating, if not fatal, effects on them.

Meanwhile, storms and temperature drops in the US and Europe could happen more often, the University of Copenhagen study said, adding that the US East Coast could also see its sea level rising, while the Amazon and the Antarctic could also be further endangered. Flooding could also be more frequent and intense.

The latest study advances earlier findings published in 2021 that also warned that the Atlantic Ocean's current system, an engine of the Northern Hemsiphere's climate, could be weakening to such extent that could bring major disruptions to the world's weather pattern.

Other climate models have said the AMOC will weaken over the coming century but that a collapse before 2100 is unlikely. That's a view being advanced by the Intergovernmental Panel on Climate Change - a Switzerland-based UN body, which is involved in studying and analysing climate crisis caused by human activities.

What is AMOC and how does it work?

The Atlantic Meridional Overturning Circulation (AMOC) is a large system of ocean currents which transports warm water from the tropics northwards into the North Atlantic.

AMOC is one of the benchmarks that scientists use in determining the Earth's "tipping point" when it comes to climate, and its collapse could signal more dangers to humanity.

The Gulf Stream is part of that system of currents, often described as a "global conveyor belt" that moves warm, salty water worldwide and helps regulate everything from the rate of sea level rise on the East Coast to Europe's average temperatures.

As the atmosphere warms due to increased greenhouse gas emissions, the surface ocean beneath retains more of heat.

At the same time, many scientists also believe that global warming itself has also contributed to more ice sheets melting, sending more freshwater mixed into the sea.

As Susanne Ditlevsen, one of the two authors of the recent AMOC report, explained in an interview with USA Today, the excess freshwater "can disrupt the normal sinking of the salty water, weakening or even shutting down the AMOC."

"If the AMOC collapses, it can have far-reaching effects on weather patterns and ocean currents, leading to significant climate changes," she said.

A potential collapse of the system could therefore have severe consequences for the world's weather systems.

Climate models have already shown that the AMOC is at its weakest in more than a 1,000 years.

If the AMOC collapsed, it would then increase cooling of the Northern Hemisphere leading to colder winters, higher level rise in the Atlantic, an overall fall in precipitation over Europe and North America and a shift in monsoons in South America and Africa, the Britain's Met Office had warned earlier.

Others

Cars sit abandoned on Chicago's Lake Shore Drive as crews work to re-open the roadway following a major blizzard in the US Midwest in January 2011, and since them more intense snowstorms have  still considered as one of the most intense snowstorms in the US to date. (Fire: John Gress/Reuters)

'Reduce greenhouse gas emissions'

Niklas Boers at the Potstdam Insitute for Climate Impact Research and author of the earlier 2021 study had already warned that the loss of dynamical stability of the current would imply that it has approached "its critical threshold, beyond which a substantial and in practice likely irreversible transition to the weak mode could occur".

By analysing the sea-surface temperature and salinity patterns of the Atlantic Ocean, the study said the weakening of the last century is likely to be associated with a loss of stability.

"The findings support the assessment that the AMOC decline is not just a fluctuation or a linear response to increasing temperatures but likely means the approaching of a critical threshold beyond which the circulation system could collapse," Boers said.

In media interviews following the publication on Tuesday of the latest AMOC study, Peter Ditlvensen, a co-author, said that evidence from past collapses of the current showed that temperature changed by as much as 10 degrees Celcius. But the last time change occurred was about 12,000 years ago during the Ice Age.

If things do not change, and if the pace of carbon emissions continue, he also said the the likeliest point of collapse is somewhere between 2039 and 2070.

With the release of the latest study, Ditlevsen is highlighting the need for governments and leaders from around the world to take action in "reducing global greenhouse gas emissions as soon as possible."

Route 6
Video Player is loading.
Current Time 0:00
Duration 0:00
Loaded: 0%
Stream Type LIVE
Remaining Time 0:00
 
1x
    • Chapters
    • descriptions off, selected
    • captions off, selected