The tipping of one element of the Earth’s system has been speculated to catalyze the tipping of others in a cascade. A new study provides an example of an alternative option in which the breakdown of one component may reduce the likelihood of another system tipping.
A brief overview of the findings. Image Credit: TiPES/HP
The study suggests that the tipping of the West Antarctica ice sheet may stabilize the significant ocean current system known as the AMOC, which distributes heat to the North Atlantic region. The research carried out by Sacha Sinet and co-workers from the Institute for Marine and Atmospheric research Utrecht, Utrecht University, the Netherlands, is published in Geophysical Research Letters.
The research is part of CriticalEarth, a Marie Skłodowska-Curie Actions Innovative Training Network program for young scientists spearheaded by the University of Copenhagen.
Global Consequences
This is a possibility that has to be explored. We need to have a better understanding of the interaction between West Antarctica and the Atlantic ocean currents to build a complete picture of possible outcomes.
Sacha Sinet, Study Author, Institute for Marine and Atmospheric research Utrecht, Utrecht University
The North Atlantic ocean current system widely recognized as the Atlantic Meridional Overturning Circulation, or AMOC for short, has the ability to tip if the Greenland ice sheet suddenly melts (collapses). This is due to the AMOC’s reliance on the formation of saltwater on the surface of Greenland and Iceland.
The seawater is diluted by large and unexpected amounts of fresh meltwater from the Greenland ice sheet. Ultimately, a tipping point can be reached, and the AMOC might slow or even stop.
A sudden shift in the AMOC would have serious implications for the global climate system. This network of ocean currents transports heat to the northern hemisphere, and the climate in the Northern Atlantic region will abruptly cool if the AMOC is not present. On a large scale, precipitation patterns and wind systems will be affected. This transition could, in a chain of events, cause the collapse of other critical climate systems.
Cascade Avoided
However, Sinet and colleagues argue that such a cascading tipping scenario could be avoided if West Antarctica's ice sheets also commit to rapid melting.
In a conceptual model of the interaction of three climate subsystems (the AMOC, the Greenland ice sheet, and the West Antarctic ice sheet), the timely collapse of the WAIS can protect the AMOC from destabilization caused by the Greenland ice sheet melting and global warming. Instead of a chain reaction of dominoes, the fall of one can prevent the fall of another.
I am still very worried about cascading. At our level of understanding, many outcomes are still possible. Also, remember that, anyhow, the loss of such climate components is a catastrophe. We still lose Greenland and West Antarctica and commit to a drastic rise of sea level. There will be dramatic consequences for our societies and ecosystems. So, whatever the end result, it is still a dramatic event. First, we must do all we can to prevent any from happening.
Sacha Sinet, Study Author, Institute for Marine and Atmospheric research Utrecht, Utrecht University
Journal Reference
Sinet, S., et al. (2023) AMOC Stabilization Under the Interaction With Tipping Polar Ice Sheets. Geophysical Research Letters. doi.org/10.1029/2022GL100305.