Physics of Complex Systems could prevent the impact of climate change

This assessment was made by Jan-Michael Rost, a researcher at the Max Planck Institute, in a roundtable discussion about complex systems and sustainability.

By Elton Alisson

Agência FAPESP – In addition to applications in fields such as Engineering and Information and Communications Technology (ICT), the Physics of Complex Systems – in which each individual element contributes to the emergence of properties that are only observed for a whole – may be useful in assessing the impacts of climate change, such as that driven by deforestation, on the planet.

This assessment was made by Jan-Michael Rost, a researcher at the Max-Planck Institute for the Physics of Complex Systems, during a roundtable discussion about complex systems and sustainability that was held on February 14, 2014, at the Hotel Pergamon in São Paulo.

The meeting, organized by the German Center for Science and Innovation São Paulo (DWIH-SP) and the Max Planck Society, in partnership with FAPESP and the German Academic Exchange Service (DAAD), is part of a complementary schedule of events associated with the Max Planck Science Tunnel Exhibition.

“Complex systems, such as life on Earth, are at the threshold between order and disorder, and take a certain amount of time to adapt to changes,” Rost said.

“If these systems are affected by huge alterations, such as the unbridled deforestation of the forests, over a short period of time, and if the threshold between order and disorder is crossed, these changes may become irreversible and place the preservation of species complexity and the potential for evolution at risk,” the researcher stated.

According to Rost, complex systems began to attract scientific attention in the 1950s, but they could not be studied using the two great theories that revolutionized physics in the 20th century: that of relativity, established by Albert Einstein (1879-1955), and that of quantum mechanics, developed by German physicist Werner Heisenberg (1901-1976) and other scientists.

Rost explained that these theories can only be applied to closed systems, such as engines, that do not experience interference from the external medium and in which reactions, which reach equilibrium on the inside, are reversible.

For this reason, he said, these theories are not sufficient for studying open systems, such as machines equipped with artificial intelligence or biological organisms on Earth that interact with the environment, are adaptable and undergo reactions that may be irreversible. Thus, these systems led to new theories related to the physics of complex systems, such as chaos theory and nonlinear dynamics, which are more appropriate for this purpose.

“The latter two theories have undergone spectacular development in recent decades, alongside the theory of classical mechanics,” Rost said.

“Today, we recognize that systems are not closed, but instead relate to what is outside, and can present reactions that are disproportionate to the action that they experience. This is what engineering is currently based on in developing products and equipment,” he said.

Categories of complex systems

According to Rost, complex systems can be divided into four categories, which differ from each other in terms of their reaction time to a particular action that they experience. The first category is that of static complex systems that react to an action instantaneously.

The second category is that of adaptive systems, such as the capacity of scent dogs. When placed in the direction of a trail left by someone who is lost in the woods, for example, scent dogs move in a zigzag pattern.

Rost says that this phenomenon occurs because the dogs have an adaptive sniffing system. In other words, when sensing the particular scent in a location, the animal’s olfactory sensitivity to that odor drastically diminishes, and he loses the ability to identify it.

In straying from the trail, the dog quickly recovers olfactory sensitivity to the odor and is able to identify it in the next footprint. “The threshold of these animals’ olfactory perception is constantly adapting,” Rost said.

The third category of complex systems refers to autonomous systems that use evolution as a system of adaptation, and it is impossible to predict what their reaction will be to a given change.

The last category is that of evolutionary, or transgenerational, systems, which is where we find human beings and other species of living things on Earth. In these living things, the reaction to a given change in their life systems takes a long time, Rost said.

“Transgenerational systems receive stimuli throughout their lives, and the reaction of a given generation cannot be compared with that of the previous one,” said the researcher.

“Trying to predict the amount of time that a transgenerational system, such as humanity, will take to react to an action such as climate change could be useful for ensuring the sustainability of the planet,” Rost concluded.