Chokepoints that concentrate global trade
Most seaborne trade flows through a small number of narrow passages where geography concentrates shipping. The Strait of Malacca (between Malaysia and Indonesia) sees roughly 25% of global maritime trade. The Suez Canal carries 12% of world trade between Europe and Asia. The Panama Canal serves the same role for trans-Pacific routes. The Strait of Hormuz (between Iran and Oman) carries roughly 20% of global petroleum trade.
These chokepoints create geopolitical leverage: any disruption cascades through global supply chains. The Suez Canal blockade in 2021 (Ever Given ship grounding) disrupted supply chains for weeks. Seasonal ice closes Arctic routes. Piracy off Somalia (now reduced) once made the Red Sea dangerous. Shipping companies and governments carefully monitor these passages because disruption triggers spot price spikes and contract renegotiations.
Hub ports concentrating traffic and transshipment
Major maritime corridors converge on hub ports: Singapore, Dubai, Hong Kong, and Rotterdam serve as transshipment centers where containers are transferred between ships without necessarily entering local distribution. A container from Shanghai to Hamburg might transship in Rotterdam, where local delivery occurs. Hub ports command premium fees and strategic importance because their location and infrastructure give them monopolistic pricing power.
The routing of trade reflects cost optimization and risk mitigation. Ships detouring around Suez (the Cape of Good Hope route) add 10-15 days and significant fuel cost, so blockades generate pressure to reopen or find alternatives. Arctic routes promise time savings but require ice-capable ships and face unpredictable ice conditions. The stability of modern chokepoints depends on political relations; major supply chain restructuring occurs if routes become unstable, such as companies reducing dependence on Suez-routed shipping after recent blockades.