A major ocean current system in the Atlantic could be on the verge of collapse as early as 2025, new peer-reviewed research shows.
This is of particular concern given the current heat extremes We are Witnesses all over the worldincluding a massive deviation from previous records in the Atlantic Ocean itself.
“Here we calculate when the early warning signs are significantly higher than the natural fluctuations.” write Physicist Peter Ditlevsen and statistician Susanne Ditlevsen from the University of Copenhagen.
“Given the importance of the AMOC to the climate system, we should not ignore such clear signs of imminent collapse.”
The Atlantic meridional overturning circulation (AMOC) is a major system of ocean currents that includes the well-known Gulf Stream and regulates the transfer of ocean heat from the tropics to the northern hemisphere.
As such, it affects much of the Earth’s climate. It is considered one of the most important tipping elements in the Earth’s climate system and is slowing down since the mid-20th century.
When it comes to a complete standstill The monsoon season is likely to be disrupted in the tropics, and Europe and North America will experience dangerously harsher winters. The knock-on effects will have a significant impact on entire ecosystems our food security.
The AMOC has only been directly observed since 2004, which is not long enough to understand the full history of its current slowdown trend.
By examining many models, the researchers identified an area of sea where sea surface temperatures most closely match ocean circulation conditions, and served as one of two less direct indicators for which records have existed since 1870.
The other early warning sign the researchers considered is the system’s “loss of resilience,” which manifests itself as increasing fluctuations and variances — like the increasing wobble of a top before it tips over.
Using these two early warning signs to assess AMOC status is somewhat similar to measuring heart rate and blood pressure to monitor heart health.
The team’s modeling suggests that this important ocean circulation could come to a halt as early as 2025, and likely by 2095 at the latest.
These findings are alarmingly ahead of the latest IPCC forecasts, but the early warning signs are already clear, argue Peter Ditlevsen and Susanne Ditlevsen.
Previous models show “tendencies towards an overestimated stability of the AMOC, both from.” Matching the historic climate recordbad representation of deep water formationsalinity and glacial runoff“, stresses the team in the newspaper.
In addition, the speed with which we encounter this destabilizing event could also determine whether the system collapses or stabilizes again.
Because not only have we failed to reduce the amount of greenhouse gases that we have pumped into the atmosphere so far – we have increased them instead – it sure looks like it’s our turn a frightening one trajectory That ocean sill mighty hard and fast to reach.
previous research has indicated that previous extreme climate variability or Dansgaard-Oeschger events were caused by this instability.
Previous studies have also shown that changing just one parameter, such as increasing the amount of freshwater entering the North Atlantic, can result in the system being adversely affected branch – result in a sudden and drastic change in system behavior.
This level of sensitivity may not have been retained in the IPCC assessment as it was not accounted for in all models included.
We still don’t understand all of the factors that might affect this system, and other researchers have argued elements such as the effects of cold water inflow do not agree entirely with previous climate records.
The researchers believe their method, which focuses on the early warning symptoms, avoids the need to fully understand these drivers, but beware: they cannot rule out some unknown unknown create a different result. They also cannot distinguish a part or a complete collapse of the AMOC, they explain.
“Despite these caveats, this is indeed a worrying finding that should require swift and effective action to reduce global greenhouse gas emissions to avoid the steady shift in the control parameter toward AMOC collapse,” the team said closes.
This research was published in nature communication.
