Structural change in the world maritime network (1880-2020): globalization, optimization, and vulnerability

Port infrastructure and related freight flows that support international trade are not distributed evenly across the globe, but are instead heavily concentrated in a few hubs and gateways. Remoteness from such key nodes is a major barrier to overall development, while overconcentration leads to the congestion and vulnerability of transport and supply chains. Advancing the maritime accessibility of smaller ports in favor of a more balanced development has so far been unsuccessful. Due to its closeness with trade and socio-economic welfare making it highly strategic, maritime connectivity has attracted international efforts to accurately measure it through a wide array of studies in the past two decades . Here we develop a novel analysis of the global maritime network, over the last 140 years (1880-2020), based on untapped vessel movement data published by the insurer Lloyd's List. Our results demonstrate that while the network has become more optimal to connect the global market, its topological and spatial structure became increasingly sparse and vulnerable to crises and shocks. We also show that contrary to what is commonly claimed, containerization prolonged rather than initiated the contemporary transformation of the maritime network.