Images of human brain activity show very clearly how different tasks are distributed among the different regions of this organ. When a person talks or reads, looks at pictures or listens to music certain parts of the brain become more active, depending on the task at hand. Some of these so-called clusters process different kinds of information. The activity of the brain’s billions of neurons is organized around these nodes, generating the typical patterns of brain activity.
“This process in a network is called Synchronization,” says Jürgen Kurths, “and nodes are the engines of Synchronization.” They determine the dynamics of interactions within the network. Identifying these so-called “hubs” in an image of brain activity is a fairly simple task. To identify them in a complex network and to describe their connections mathematically is challenging. When a network is made up of many interacting elements, like the about one hundred billion neurons of the human brain, highly complex dynamical patterns may arise.
The Earth system, too, can be regarded as a complex network. Kurths’ methods of analysis can point at the regions around the globe that decisively influence climate dynamics. Enhanced climate modeling could reveal where hidden connections between distant components of the Earth system lie. Kurths was able to describe how the Pacific climate phenomenon El Niño is connected to the Indian monsoon (Abstract).
The ability of current models to simulate abrupt climatic changes is limited. Such sudden changes can occur in connection with the “tipping elements” of the Earth system. One of the best known examples of a tipping element is the Greenland ice sheet. Even at the current rate of ice loss, a critical threshold may already have been reached where the process becomes self-energizing and unstoppable. Other potential tipping elements are the Arctic sea ice, the growth of the Amazon rainforest or the system of currents in the Atlantic Ocean.
However, even with models that can represent nonlinear processes, it would not be possible to predict exactly when such elements could tip. “But we want to be able to estimate how close we are to the critical thresholds,” Kurths says. Analyzing these risks would help to map out strategies to mitigate dangerous climate change and to adapt to its unavoidable impacts.
“Looking at the Earth system as a complex network is an innovative and fruitful approach”, says Hans Joachim Schellnhuber, the Director of PIK. Kurths’ research would not only advance the analysis of the Earth system, modeling or adaptation to climate impacts, it would also tackle crucial technological challenges such as the transformation of the energy system. One of the current issues in research is the construction of intercontinental power grids. If Europe’s power supply is to be generated in offshore wind parks or solar power stations in the Sahara, the transmission needs to be low in loss. Here, too, analysis of nonlinear dynamics can make valuable contributions and point out solutions.
Inaugural lecture by Prof. Dr. Dr. h. c. Jürgen Kurths:
Synchronization in complex networks – Theory and Applications in Life and Environmental Sciences
Time:
Tuesday, 13.01.09, 15:15 until 17:00
Place:
Physics Institute
Campus Adlershof
Humboldt-Universität Berlin
Lise-Meitner-Haus
Christian-Gerthsen-Hörsaal
Lise Meitner-Haus
Newtonstrasse 15
12489 Berlin
Kurths’ homepage at PIK:
http://www.pik-potsdam.de/members/kurths
For further information please contact the PIK press office:
Phone: +49 331 288 2507
E-mail: press@pik-potsdam.de
