Maritime chokepoints concentrate shipping flows into narrow routes. The Suez and Panama disruptions show what happens when traffic is diverted: goods can keep moving, while voyages become longer, slower, and more expensive.
A chokepoint shock changes effective shipping capacity by forcing longer routes, even when the number of vessels does not change.
Where trade becomes concentrated
In this article, a maritime chokepoint means a route whose disruption can redirect a substantial volume of shipping onto longer paths. The exposure is large because, according to UN Trade and Development's 2024 review, over 80% of world trade volume is carried by sea.
The Suez and Panama Canals illustrate two forms of concentration. The International Monetary Fund's March 2024 analysis describes the Suez Canal as the shortest maritime route between Asia and Europe and says that about 15% of global maritime trade volume normally passes through it. The Panama Canal usually accounts for about 5%.
Their importance lies in route substitution. When passage declines, diverted ships travel farther, deliveries arrive later, and the shipping system must provide more transport work.
How distance becomes a capacity constraint
Ton-miles combine cargo weight with distance traveled, so the measure rises when the same cargo takes a longer route. In 2023, seaborne cargo volume grew by 2.4% to 12.3 billion tons, while ton-miles rose by 4.2%. UNCTAD attributed the faster growth in ton-miles to longer shipping distances caused by disruptions on routes including the Suez and Panama Canals.
By mid-2024, longer routes had raised global vessel ton-mile demand by 3% and container-ship demand by 12%.
Read together, UNCTAD's figures support an operational interpretation: a longer voyage uses more vessel-distance for each delivery and keeps the vessel committed for longer. The fleet must therefore provide more transport work to move cargo over the longer route. This is how route length can strain shipping capacity without reducing the number of ships.
Two disruptions and two detours
Attacks on vessels in the Red Sea area reduced traffic through the Suez Canal, leading several shipping companies to divert ships around Africa's Cape of Good Hope. In the first two months of 2024, Suez Canal trade volume fell 50% from a year earlier, while estimated trade volume around the Cape rose 74%. The IMF reported that the diversion increased delivery times by 10 days or more on average.
The Panama disruption had a different cause. Severe drought forced canal authorities to restrict daily ship crossings. Trade through the canal fell almost 32% year over year in the first two months of 2024, and UNCTAD reported that the disruption increased sailing distances by 31% for affected routes.
Traffic subsequently developed differently at the two canals. UNCTAD's October 2024 update reported that Suez averaged 33 transits per day by mid-October, 55% lower than one year earlier and only 4% above its lowest recorded four-week average. Panama's four-week average was 30 transits per day, 4% lower than one year earlier and 40% above its early-2024 low.
The sources use different measures and observation windows for Cape rerouting. The IMF estimated a 74% year-over-year increase in Cape trade volume during the first two months of 2024, while UNCTAD reported an 89% rise in rerouted vessel capacity by mid-2024. These figures describe different quantities and periods, so they should not be treated as interchangeable estimates of one rerouting rate.
The cost stack created by rerouting
Across its two reports, UNCTAD links longer routes or rerouting with increased fuel consumption, crew wages, insurance premiums, chartering costs, port congestion, piracy risks, delays, and carbon emissions.
One container-freight benchmark moved sharply over the same period. By mid-2024, the Shanghai Containerized Freight Index had more than doubled from late 2023. UNCTAD treated the persistence of higher shipping costs as a condition in its consumer-price projection: if sustained, they would increase global consumer prices by 0.6% by 2025.
The projected effect was larger for small island developing States. UNCTAD estimated a 0.9% increase in their consumer prices and a 1.3% increase in processed-food costs. It also reported that their shipping connectivity had fallen 9% over the preceding decade, leaving them ten times less connected than the rest of the world.
UNCTAD's comparison suggests that lower existing connectivity can amplify the consequences of a common shipping-cost shock for some economies. This is a reading of the reported contrast, rather than a separately measured causal effect in the supplied figures.
Rerouting can complicate economic measurement
The IMF reports that the temporary impact of rerouted ships can affect customs-based import and export statistics, making the underlying momentum of trade and economic activity harder to assess. It does not specify the exact accounting mechanism, so the supported conclusion is limited: during rerouting, customs data may provide a less clear signal of underlying trade momentum.
Read together, the three reports suggest a practical tracing sequence: canal traffic shows the initial interruption; Cape traffic identifies rerouting; delivery-time, ton-mile, and vessel-demand measures show the added transport burden; freight indices show pressure in shipping markets; and customs statistics and conditional consumer-price projections show possible later economic effects. This sequence organizes the reported observations, but it does not establish every causal link or isolate product-level pass-through from other causes of price changes.
The consequences depend on the cargo and the market waiting at the other end. Fertilizer, Nitrogen, and Food Security traces one commodity system in which concentrated production and export policy already make transport conditions consequential.