The Strait League Table
A comparative view of twelve maritime passages, distinguishing source data, IPSC assessments and IPSC model outputs. Eight South China Sea rows use a common 2024 merchandise-trade valuation from CSIS. Four connected global gateways are included as contextual comparators but remain outside the monetary model rankings until a harmonised merchandise-value input is available.
Ranking the comparable rows
The eight 2024 CSIS merchandise-value rows can be ranked on a common basis. Four global gateways remain visible but show n/c where no harmonised merchandise-value input has been established. “Delay exposure” is the value of reroutable cargo held in transit for additional days; it is not an estimate of economic loss.
| #▼ | Chokepoint▼12 passages | Pressure▼IPSC current assessment | Trade value▼2024 merchandise basis where comparable | Redundancy▼IPSC scored · higher = safer | Extra days▼route-family range | Delay exposure▼IPSC modelled midpoint + range | Non-reroutable▼30-day flow · modelled range | Largest quantified user▼only where evidence supports it |
|---|
Key findings
Comparable findings grounded in common-source data and clearly identified physical-flow evidence.
Malacca and Taiwan remain in a league of their own
CSIS estimates US$2.459tn through Malacca and US$2.449tn through the Taiwan Strait in 2024 — approximately 21% of global maritime trade each. These values are directly comparable because they use the same modelling architecture and base year.
Most Malacca traffic can use alternative routes
CSIS identifies Sunda, Lombok–Makassar and, in a worst case, routing around Australia as substitutes for Malacca traffic. The model therefore applies a 0–3% non-reroutable range to a standalone closure and marks the estimate low confidence.
Australia is the concentration outlier
Australian exports account for 88% of Lombok trade, 60.5% of Makassar trade and 44.4% of Mindoro trade. These are among the strongest country-level findings on the page.
Hormuz is different, not directly comparable
EIA shows why Hormuz remains exceptional: it carries more than a quarter of global seaborne oil trade and around a fifth of global LNG trade on the 2024 baseline, while available Saudi/UAE bypass capacity is only about 2.6m b/d. The model does not convert that physical exposure into a merchandise-value rank without a harmonised valuation method.
Global gateways are contextual comparators
Official authorities provide strong physical and operational data, but not a merchandise-value series constructed on the same basis as the CSIS strait data. These passages are therefore shown as contextual comparators and withheld from the comparable monetary ranking.
Do not sum the rows
A cargo can cross several chokepoints on one voyage. The same Middle East–Northeast Asia cargo may appear at Hormuz, Malacca and Taiwan. Per-strait values therefore do not form a regional total, and correlated closures require a network model rather than arithmetic addition.
Scoring methodology
Pressure and redundancy are IPSC assessments, not externally measured statistics. The scoring rule is stated below, with every component displayed in the supporting evidence for each row.
D = current disruption · C = conflict proximity · K = coercive/closure risk · O = navigational/operational stress
Redundancy = 0.35R + 0.25T + 0.25A + 0.15M
R = alternate-route quality · T = detour efficiency · A = substitute-route capacity · M = non-maritime bypass
| Component | How it is coded |
|---|---|
| Pressure components | Analyst-coded in 25-point bins: 0, 25, 50, 75, 100. The score is date-stamped and is not a probability of closure. |
| Route quality (R) | 0 = no substitute; 20–60 = one partial/full substitute; 100 = multiple viable maritime route families. |
| Detour efficiency (T) | 100 ≤1 day; 85 = 1–3 days; 65 = 3–7; 35 = 7–14; 15 >14; 0 where no full maritime reroute exists. |
| Capacity (A) | Analyst-coded ability of substitutes to absorb traffic without the original passage. Physical possibility is distinguished from economic efficiency. |
| Non-maritime bypass (M) | Road, rail or pipeline substitution where material. A high value does not mean the substitute is equally cheap or scalable. |
How the model outputs are built
Only the eight rows with a comparable 2024 merchandise-value denominator receive monetary model outputs. Both outputs are ranges; the table ranks on the midpoint solely for display.
value of reroutable cargo kept in transit for additional days — not economic loss
30-day non-reroutable flow = (annual trade ÷ 365) × s × 30
trade flow assumed unable to use an alternative route under the stated closure scenario — not GDP loss
- Ranges replace false precision. Each row states a low/high non-reroutable share and a corridor-specific detour band. The midpoint is a display convention, not an observed value.
- Standalone closure scenario. The South China Sea workpapers model one passage unavailable while other route families remain open. A Taiwan war, multi-strait closure or regional blockade requires a correlated-disruption model.
- Capacity congestion is not automatically “stranded.” Cargo that can physically reroute but waits, queues or pays more remains in the delay-exposure side of the model.
- Global gateways are withheld from the monetary ranking until IPSC has a harmonised merchandise valuation comparable with the CSIS 2024 dataset. Physical-flow evidence remains displayed in their row workpapers.
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