Colloquium on December 17th, 2007


Dirk Brockmann
MPI for Dynamics and Self-Organization, Göttingen

New perspectives on global human traffic, scaling laws and emergent geographic communities

Travel in our globalised world has reached a complexity and volume of unprecedented degree. More than 60 million people travel billions of kilometres on more than 2 million international flights each week. Hundreds of millions of people commute on a complex web of highways and railroads most of which operate at their maximum capacity. Human mobility is responsible for the geographical spread of emergent human infectious diseases and plays a key role in human mediated bioinvasion, the dominant factor in the global loss of biodiversity.
I will report on the recent discovery of scaling laws in global human traffic (obtained from online bill-tracking at www.wheresgeorge.com, Brockmann et al. Nature, 2006) and mathematical models that can account for it. I will present a complex network perspective on multi-scale human traffic networks, report on their statistical properties and show that they can be used to identify geographically coherent communities which only vaguely resemble those provided by geopolitical ones and that provid an operational segmentation of maps into a hierarchical set of regions and boundaries.