The findings suggest that prior to the Little Ice Age, the North Atlantic climate system lost its resilience and became disrupted, potentially forcing it to “flip” into a new, cooler state.
Studying the Little Ice Age reveals new insights into the North Atlantic climate system.
Scientists examined centuries-old oyster shells to determine how the North Atlantic climate system reached a “tipping point” before the Little Ice Age. The Little Ice Age, the period of particularly pronounced regional cooling in the North Atlantic, lasted several centuries and ended around 1850.
A longstanding theory states that the initial cooling of this period was maintained by “reactions from sea ice to ocean”. As sea ice expanded, ocean currents slowed, which in turn reduced the flow of warm water from the south.
The University of Exeter He conducted a new study that looked at how the ocean has changed and responded to external changes over the past few centuries by using cohoj oyster shells, which can survive for several hundred years.
The results show that the North Atlantic climate system lost elasticity (the ability to recover from external changes) and was disrupted before the Little Ice Age, which could have caused it to “flip” into a new colder state. Furthermore, according to experts, a new turning point in the North Atlantic could be near, which will have serious consequences for the climate of the region.
The work is helping our understanding of how and when points of no return are activated, which is important as scientists have warned that many points of no return may now be approaching around the world due to climate-driven change. by man.
“One way of saying that a system is approaching sudden transformation is that it becomes slow to respond to perturbations (external changes),” said lead author Beatrice Arellano-Nava of the World Systems Institute in Exeter. In other words, the system loses the ability to return to its normal state and may instead “tend” to a new state.
said Dr. Paul Halloran, who co-directed the research.
The new study warns that the vulnerability of the North Atlantic system is a critical issue today, with recent analyzes indicating it has destabilized over the past century and may be nearing a tipping point.
“Our latest analysis indicates that the ocean current system in the North Atlantic may now be at risk of capsizing again due to global warming, triggering abrupt climate change in Europe again,” said Professor Tim Linton, director of the World Systems Institute.
Shell analysis focused on oxygen, carbon isotopes and shell growth, all of which can be used as measures of environmental change.
Reference: “Destabilization of the Arctic Atlantic Before the Little Ice Age” by Beatrice Arellano-Nava and Paul R. Halloran and Chris A. Bolton, James Scores, Paul J. Butler, David J. Reynolds and Timothy M. Linton, 25 August 2022, Available here. <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="
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DOI: 10.1038 / s41467-022-32653-x
The study was funded by the European Union’s Horizon 2020 research and innovation program.
