Cities, Diversity, and Global Maritime Networks

Abstract

Maritime transport is often overlooked in urban network studies, just like cities rarely appear in shipping network analyses. However, this particular vector carries the vast majority of international trade volumes, and two-thirds of the world’s population resides in coastal areas. From a complex network perspective, this article tests the interdependencies between maritime flows and the urban hierarchy. Nearly 4 million vessel movements connecting about 6000 ports are computed to shed new light on the affinity between traffic volume, diversity, connectivity, interaction range, and city size. Main results point to the high and maintained dominance of the largest cities over three decades (1977–2008), thereby demonstrating that maritime networks are subject to urban regularities in ways similar to other transport and communication networks, despite deep contemporary changes in the distribution of port systems and supply chains. This research also underlines the need to extend the spatial unit under investigation to better catch urban effects.