Source: Jan Hoffmann / UNCTAD. Container-to-general cargo ratio derived from the registered fleet in dwt. Dry-to-bulk ratio derived from ton-kilometers transported. Transportation / inventory costs ratio derived from USA data from the Council of Supply Chain Management Professionals, State of Logistics Report, (after 2012). Logistics Management & Distribution Report (before 2012).
In recent decades, notable changes have been seen in the composition of maritime shipping services. The ratios depicted in the above figure underline these changes:
- An important aspect is the ongoing containerization of the breakbulk trade, which implies a quickly rising container-to-general cargo tonnage ratio. The cost and operational efficiency of container shipping have substituted for conventional breakbulk shipping, which mainly serves niche markets such as project cargo and vehicles (RORO vessels).
- The globalization of maritime shipping has resulted in a growing share of the fleet being registered in a foreign country. The ratio between the total tonnage registered in a foreign country compared to nationally registered tonnage has increased.
- While liquid bulk trade, such as petroleum, used to be the dominant cargo carried by maritime shipping, the share of dry cargo, such as minerals, grain, and containers, has increased. This is the outcome of several trends, including the stabilization of petroleum imports from Europe and North America due to energy efficiency, a shift to other sources of energy (e.g. natural gas), and domestic production (e.g. American shale oil). Further, several developing economies, including China, have become large importers and exporters of dry cargoes such as iron ore and coal.
- The shift in the logistical components of maritime trade is also indicative. Using evidence from the United States, the share of transportation costs over inventory carrying costs has increased. This implies that a growing share of the inventory is in transit, particularly since container shipping costs have been on a downward trend. An important aspect has been applying lean supply chain management and “just-in-time” strategies that result in lower inventory levels.