People are well aware of the regular warnings that climate change might result in ‘tipping points’: irreversible situations where savanna can rapidly get transformed into desert, or the warm gulf stream current can just stop flowing.
Spatial pattern formation of mussels and diatoms on a tidal flat. This pattern formation allows tipping points caused by sea-level rise to be evaded so that tidal flats do not drown. The spatial patterns on the tidal plate, including the waves, are based on mathematical model simulations. Image Credit: ©Johan van de Koppel/Ulco Glimmerveen (birds).
Such alerts frequently relate to spatial patterns as early-warning signals of tipping points. An international group of ecologists and mathematicians has studied these patterns and has come up with an unexpected conclusion.
“Yes, we need to do everything we can to stop climate change. But the earth is much more resilient than previously thought. The concept of tipping points is too simple,” the authors stated this in full agreement with the new IPCC report.
Their research work has been recently published in the authoritative journal Science.
The study builds on years of partnership between several research institutes in the Netherlands and abroad, particularly between Utrecht University and Leiden University. The scientists approached the concept of a tipping point inside a spatial context.
The formation of spatial patterns in ecosystems, like the spontaneous formation of complex vegetation patterns, is often explained as an early-warning signal for a critical transition. But these patterns actually appear to allow ecosystems to evade such tipping points.
Max Rietkerk, Study Lead Author and Professor, Spatial Ecology and Global Change Ecologist, Utrecht University
Such outcomes depend on mathematical analyses of spatial models and new observations gathered from real-world ecosystems.
Alan Turing
The patterns emerging freely in nature are frequently referred to as “Turing patterns.” It has been named after the famous British mathematician Alan Turing. In 1952, he explained the way in which patterns in nature, like the stripes on animals’ coats, would have the ability to develop from a homogeneous starting position.
In ecological science, the Turing patterns are often explained as early-warning signals, because they indicate disturbance. Turing’s mechanism of pattern formation is still undisputed. But the fact that a pattern is forming somewhere does not necessarily mean that an equilibrium is disrupted beyond a tipping point.
Arjen Doelman, Study Co-Author and Mathematician, Leiden University
As an instance of such a situation, Rietkerk cites the transition from savanna to the desert. “There you can observe all sorts of complex spatial forms. It’s a spatial reorganization, but not necessarily a tipping point. On the contrary: those Turning patterns are actually a sign of resilience.”
Evading Tipping Points
An interesting new phenomenon in ecology, known as multistability was discovered by scientists. It suggests that numerous different spatial patterns can take place concurrently under the same circumstances.
And each of these patterns can remain stable under a wide range of conditions and climate change. And moreover, we found that any complex system large enough to generate spatial patterns may also evade tipping points.
Max Rietkerk, Study Lead Author and Ecologist, Utrecht University
The study questions which systems are currently sensitive to tipping, and which are not.
Rietkerk stated, “That means we have to go back to the drawing table to understand the exact role of tipping points. Only then can we determine which conditions and spatial patterns result in tipping points, and which ones do not.”
Journal Reference:
Rietkerk, M., et al. (2021) Evasion of tipping in complex systems through spatial pattern formation. Science. doi.org/10.1126/science.abj0359.