Shipping and Chokepoints
The physical infrastructure of global trade. Container ships, port concentration, the major chokepoints, and why disruption at any of them ripples through the entire world economy.
(UNCTAD; the figure is over 70% by value, since high-value goods are more often air-freighted)
(Alphaliner; plus tens of thousands of bulk carriers, tankers, and other vessels)
(Hormuz, Suez, Bab el-Mandeb, Malacca, Panama, Bosporus/Dardanelles)
A note on framing. Most of what people consume in developed economies arrives through a global shipping system that is largely invisible until it stops working. The Suez blockage in 2021, the Houthi disruption of Red Sea shipping from late 2023, the Panama Canal drought of 2023-24, and the COVID-era port congestion of 2020-22 each made the system briefly visible and then receded from attention. The Strait of Hormuz, restricted since March 2026, has kept it in view far longer. This page walks through the underlying picture so a reader can place these episodes in context. It covers how the actual shipping system works, where the real chokepoints are, and why disruption at any of them matters more than the shipping industry's share of GDP would suggest.
How global shipping works
The container revolution, which began in the late 1950s and matured through the 1970s and 80s, transformed shipping from a labor-intensive port-based industry into the standardized, high-volume system that makes globalization cost-effective. A standardized steel box (the twenty-foot-equivalent unit, or TEU) moves seamlessly between ships, trains, and trucks. The cost of shipping a box from Shanghai to Los Angeles can multiply several times during disruption; Drewry's benchmark for the route stood at about $7,800 for a 40-foot container (two TEU) in late September 2026. Even so, it is small relative to the value of typical container contents, so distance constrains global production decisions far less than it used to.
The fleet structure. The container fleet is dominated by a few alliance groupings, and the ten largest carriers operate about 85% of its capacity (Alphaliner, September 2026). The largest are MSC (Switzerland-based, with over a fifth of global capacity), Maersk (Danish), CMA CGM (French), COSCO (Chinese state-owned), Hapag-Lloyd (German), ONE (Japanese consortium) and Evergreen (Taiwanese). The end of the 2M Alliance (Maersk and MSC) in January 2025 and the formation of new alliances (Gemini, Premier) reshuffled the operational map but did not change the underlying concentration.
The port system. Major container ports cluster around a relatively small number of locations: Shanghai, Singapore, Ningbo-Zhoushan, Shenzhen, Guangzhou, Qingdao, Busan, Tianjin, Hong Kong, Rotterdam, Antwerp, Hamburg, Los Angeles-Long Beach, New York-New Jersey, and a handful of others. Roughly a third of global container throughput moves through Chinese ports, and six of the ten busiest container ports in the world were in mainland China in 2025. The ten largest ports together handle a large fraction of global activity. New port construction is slow because of land, capital, and political requirements; the existing concentration is durable.
The other categories. Container shipping is the most visible category but not the largest by tonnage. Bulk shipping moves grain, ore, coal, and similar commodities; tanker shipping moves oil, gas, and chemicals; specialized vessels handle car carriers, livestock, refrigerated cargo. Each has its own market structure, route patterns, and chokepoint sensitivities.
The financial structure. Shipping is unusually opaque financially. Vessel ownership is often layered through holding companies in flag-of-convenience jurisdictions. Liability and insurance arrangements are byzantine. The legal frameworks (admiralty law, the Hague-Visby Rules, the not-yet-in-force Rotterdam Rules, various national variations) are specialized. The result is an industry where ownership, operation, control, and beneficial interest can be in different places, which has implications for sanctions enforcement, environmental regulation, and crisis response.
The major chokepoints
Six maritime chokepoints concentrate enough trade flow that disruption at any of them produces global effects. Each has its own geography, vulnerabilities, and current status.
Strait of Hormuz. The 21-mile-wide passage between Iran and Oman through which about a fifth of the world's oil consumption and of its liquefied natural gas (LNG) trade passed in 2024. For years the pattern of US-Iranian tension produced only periodic incidents - vessel attacks, Iranian seizures of foreign-flagged ships, occasional military exchanges - and sustained closure was treated as a scenario rather than a fact. That changed on February 28, 2026, when Iran closed the strait to normal commercial traffic after American and Israeli strikes. The International Energy Agency called the resulting supply disruption the largest in the history of the oil market. Brent futures rose more than 60% in March, their largest monthly gain since records began in 1988 (the monthly average rose about 45%). Apart from a partial reopening under a June memorandum that collapsed in July, the strait has stayed restricted. IMF PortWatch counted about 4 transits a day in September against 85.5 in 2025, though many tankers now cross with their transponders off. By late August the International Maritime Organization (IMO) had verified at least 70 attacks on ships since the war began, with 19 seafarers killed and up to 400 ships stuck in the Gulf. The United States has blockaded Iranian ports since mid-July; US-Iranian talks on a phased reopening had produced no deal by September 26.
Suez Canal. Connects the Mediterranean and the Red Sea, allowing Asia-Europe trade to bypass the Cape of Good Hope. Roughly 12-15% of global trade by volume passes through Suez in normal conditions. The 2021 Ever Given grounding blocked the canal for six days and produced billions in disruption. The canal is operated by Egypt, with major reconstruction completed in 2015 to allow two-way transit on parts of the route. Transits averaged about 41 a day in September 2026, against 74 in 2023 (IMF PortWatch).
Bab el-Mandeb. The 18-mile-wide passage between Yemen and Djibouti at the southern end of the Red Sea. Connects Suez to the Indian Ocean. Houthi attacks on commercial shipping from late 2023 through 2024-25 forced major rerouting around the Cape of Good Hope. The Houthis paused after the Gaza ceasefire of October 2025, but in July 2026 they declared a blockade of Saudi ports and shipping; they have since claimed strikes on several Saudi tankers, and Saudi Arabia has struck Houthi positions from the air. Transits averaged about 26 a day in September, against 74 in 2023 (IMF PortWatch).
Strait of Malacca. The roughly 500-mile passage between Malaysia, Indonesia, and Singapore through which roughly 30% of global shipped trade passes. The narrowest point is about 1.7 miles wide. Singapore, at the southern end, is among the world's largest container ports and a major bunkering hub. Malacca is also the principal route for Chinese energy imports, which has produced sustained Chinese investment in alternative routes (the China-Pakistan Economic Corridor, Belt and Road infrastructure across Myanmar).
Panama Canal. Connects the Atlantic and Pacific. Roughly 5% of global trade by volume. The 2023-24 drought reduced freshwater availability in the Gatun Lake reservoir that feeds the canal locks, forcing transit reductions and rerouting. Traffic recovered in 2025, but low rainfall and El Nino led the canal authority to cut daily booking slots and the maximum draft again from September 2026; the climate-related vulnerability is established. New Panamax-size vessels (built to fit the expanded 2016 locks) constrain alternatives.
Bosporus and Dardanelles. The Turkish straits connecting the Black Sea to the Mediterranean. Critical for Russian, Ukrainian, and broader Black Sea grain and energy exports. The Montreux Convention (1936) governs Turkish administration; since 2022 Turkey has used it to close the straits to Russian and Ukrainian warships, except those returning to their home bases. The straits are narrow, congested, and pass through densely populated Istanbul; periodic accidents occur and would have substantial consequences if scaled. Transits fell to about 54 a day in September 2026 from 92 in 2025 (IMF PortWatch), amid what the IMO calls a significant increase in drone attacks on tankers and grain ships in the Black Sea.
When chokepoints close: the cascade pattern
What makes chokepoints important is not the direct cost of rerouting around them but the cascade effects through the broader system. A specific case study illustrates the pattern.
The Houthi disruption of late 2023 onward. Houthi forces in Yemen, in stated solidarity with Palestinians in Gaza after October 2023, began attacking commercial shipping in the Red Sea and Gulf of Aden. Initial incidents involved missiles and drones; some vessels were boarded; one was sunk. Major shipping lines began rerouting around the Cape of Good Hope by December 2023.
The cascade: the rerouted Asia-Europe voyage takes 10-14 additional days. Vessel utilization drops because each ship completes fewer round trips per year. Effective fleet capacity is reduced even though no ships have been lost. Container freight rates from Asia to Europe rose roughly 200-300%. Insurance rates rose substantially for vessels still using the Red Sea. European supply chains experienced delays of two to four weeks. Specific products with tight inventory cycles (automotive parts, fashion seasonality, fresh produce) faced acute disruption. Manufacturing in Europe slowed in industries dependent on Asian inputs. The inflation effect was modest at the headline level but real in specific sectors.
None of this required the chokepoint to be physically closed. It required the route to be considered unsafe enough that major operators chose alternatives. The Houthi capability was modest by military standards; the leverage came from operating against ships in a narrow waterway where defending each individual vessel was infeasible.
The general pattern is that chokepoint disruption produces three categories of cost: direct rerouting cost (more fuel, more time), capacity reduction (the rerouted fleet does less work per year), and downstream supply-chain effects (companies relying on the rerouted goods face delays, work-arounds, or stockouts). The third category is consistently the largest and the hardest to anticipate.
The decarbonization challenge
Shipping accounts for roughly 3% of global greenhouse-gas emissions, making it comparable to a major emitting country if treated as one. The International Maritime Organization's 2023 strategy targets net-zero by around 2050 with intermediate milestones. Whether this is achievable is contested.
The technical pathways are partial. Ammonia, methanol, and hydrogen are the leading candidate fuels for deep-sea shipping; each has substantial cost, infrastructure, and safety challenges. Battery-electric is feasible only for short-distance routes. LNG provides modest emissions reduction relative to fuel oil and is being adopted as a transition step but is not net-zero compatible. Wind-assist technologies (rotors, sails, kites) reduce fuel burn modestly. Slow steaming (operating ships at lower speeds) reduces emissions per voyage but increases fleet capacity needs.
The economics are difficult. Alternative fuels have typically cost two to four times as much as conventional fuel oil. Vessel investment is long-lived (30-year typical life), so newbuild decisions made now lock in technology for decades. Port bunkering infrastructure for alternative fuels is being developed in parallel but is not at scale. The political-economy challenge is that shipping competes globally on cost; unilateral environmental costs disadvantage individual operators and flag states.
Carbon pricing at the IMO has stalled. In October 2025, after opposition led by the United States and Saudi Arabia, its members voted 57 to 49 to postpone for a year the adoption of its Net-Zero Framework, a global fuel standard with a price on emissions above it; the session is due to resume on December 4, 2026. The EU's inclusion of shipping in its Emissions Trading System from 2024 was a meaningful step. Whether the global regime catches up to the targets it has set will be one of the central tests of multilateral environmental governance over the next decade.
The paths from here
Continued steady-state with periodic disruption
The system continues to function well most of the time and to produce periodic visible disruption (every few years, on average) when specific chokepoints come under stress. Capacity expansion through new vessels and modest port investment keeps pace with demand. No major restructuring of routes or alliances. This remains the most likely trajectory once the Gulf war ends (the EIA expects Gulf oil flows to recover by mid-2027), though since 2020 major disruptions have come almost yearly.
Sustained Hormuz disruption changes the energy map
This one has now been tested rather than modeled. The 2026 closure drew down strategic reserves, pushed part but not all of the volume through the alternative routes (the East-West pipeline across Saudi Arabia, the UAE-to-Fujairah line), and moved oil further and faster than most pre-war estimates had assumed. The bypasses proved exposed too: Saudi Arabia shut the East-West line on September 12 after strikes by drones it said came from Iraq. What remains open is how long the restriction, now seven months old, will last, and whether the rerouting capacity built in response makes the next one cheaper or simply normalizes the risk premium.
Climate-related chokepoint pressures intensify
Panama Canal drought conditions (back in 2026), Arctic sea-ice changes affecting Northern Sea Route viability, sea-level effects on low-lying ports. Shipping-system adaptation is incremental; specific routes shift; the Northern Sea Route becomes commercially viable for more of the year (with substantial environmental and geopolitical complications). The map changes slowly but visibly.
Decarbonization accelerates faster than expected
The combination of regulation, fuel-cost dynamics, and alternative-fuel infrastructure investment moves fast enough to put net-zero shipping within plausible reach. Specific firms (Maersk's methanol-fueled vessels, others) become commercial models. The cost premium of alternative fuels narrows. This is the optimistic case; its next test is the postponed IMO vote due in December 2026.
Geopolitical fragmentation reshapes shipping
Continued US-China tension, sanctions enforcement against Russia and Iran, and broader bloc dynamics fragment the previously globalized shipping system. US port fees on Chinese-built and Chinese-operated ships, and China's retaliatory fees, took effect in October 2025 and were suspended a month later under a trade truce now set to run to January 2027. Specific routes become politically constrained. Sanctioned tonnage shifts to flag-of-convenience and shadow fleet operations. The system continues to function but in a more partitioned way.
Where serious analysts disagree
Chokepoints are overemphasized as strategic vulnerabilities
Modern shipping is more resilient than alarmist coverage suggests. Rerouting around chokepoints adds cost but the system continues to function: even with the Red Sea diversions and the 2026 Hormuz closure, the WTO still expected in July that world trade would grow in 2026. The strategic worry about chokepoints reflects military-strategic thinking that does not match commercial-shipping reality.
Held by: Lars Jensen (Vespucci Maritime), parts of the academic shipping-economics community, and a strand of practical-shipping commentary. The case has empirical support in actual disruption recovery.
Chokepoints are underemphasized relative to systemic effects
Direct disruption costs are small; the cascade through manufacturing, just-in-time supply chains, and consumer prices is much larger and harder to model. The 2021 Suez blockage and the 2024 Houthi disruption each had effects on global manufacturing and inflation that remain partly invisible because they are diffuse rather than concentrated. The strategic risk is real and is systematically underweighted by commercial actors with normal time horizons.
Held by: parts of the Center for Strategic and International Studies (CSIS) maritime-security work, several major reinsurers' research divisions, and a strand of supply-chain-resilience research. The case has been strengthened by post-2020 supply-chain disruption experience.
The Chinese position is the most consequential variable
Chinese state-owned shipping operators, port investments globally (Belt and Road port infrastructure across more than 50 countries), and shipbuilding capacity (China builds more than half of new commercial vessels) collectively give China leverage in maritime trade that is poorly understood in Western strategic thinking. The implications during a major confrontation are substantial.
Held by: the US Naval War College and its China Maritime Studies Institute, parts of CSIS, and a strand of US Navy strategic thinking. The case, long confined mainly to technical literature, entered US trade policy with the port-fee investigation of 2024-25.
Decarbonization timelines are unrealistic
The IMO net-zero targets and the EU's shipping-emission targets are not achievable on the proposed timelines given the alternative-fuel cost, infrastructure development pace, and political-economic constraints. The targets will be missed substantially; either the timelines are revised, or the targets are formally maintained while informal slippage continues. The current trajectory implies the latter.
Held by: parts of the practical shipping-industry community, several maritime economists, and a strand of climate-policy realism. The case has empirical support on the cost-and-infrastructure side.
The shadow fleet is the most consequential 2026 development
The Russian (and partly Iranian, Venezuelan) shadow tanker fleet that has emerged to bypass sanctions has reached substantial scale, often operating with weak regulatory oversight, dubious insurance, and aging vessels. Environmental-incident risk is elevated. The legal-and-political framework for handling these vessels is underdeveloped. Specific incidents (oil spills, vessel accidents, port-state control disputes) could produce major consequences.
Held by: the maritime-sanctions enforcement community (US and UK sanctions authorities), insurance market regulators, and several investigative-journalist groups. The case has empirical support in actual fleet documentation.
What the available evidence actually supports: the global shipping system is remarkably efficient and remarkably exposed to a small number of geographic chokepoints. The cascade effects through global supply chains are larger than the direct shipping disruption costs. The Chinese position is important, decarbonization is a real challenge whose timelines are likely to slip, and the shadow fleet is producing real but under-priced risk.
What this means for you
If you read trade or supply-chain coverage
Specialized sources (Lloyd's List, TradeWinds, gCaptain, the Shipping & Logistics newsletters) provide much more detail than mainstream coverage. When you see headlines about specific shipping disruptions, the question to ask is which chokepoints are involved, what the actual rerouting cost is, and which downstream industries are affected. The answer is usually more specific and more interesting than the headline suggests.
If you do business with international supply chains
Resilience measures that were unfashionable in the 2015-19 just-in-time era have become more widely valued: secondary suppliers, geographic diversification of supply, modest inventory buffer, alternative-route mapping. The cost of these measures is real; the cost of not having them showed up clearly during 2020-22, again during 2023-24, and in 2026. Specific industries (semiconductors, pharmaceuticals, automotive) have invested substantially; many others have not.
If you make major purchasing decisions
Shipping-cost and timing dynamics affect what is available and at what price. The seasonality of major retail products (back-to-school, Christmas, others) and specialized inventory (fresh food, particular industrial goods) is more sensitive to disruption than steady-state commodity goods.
If you live near a major port or shipping route
The local economic and environmental effects of major port operations are substantial, especially for low-lying coastal communities and trucking-corridor neighborhoods. The decarbonization transition will reshape port operations significantly over the next two decades. Local engagement on port environmental and labor decisions is one of the higher-leverage forms of civic involvement available.
If you vote on trade or industrial policy
Shipping is the physical substrate of the trade system that policy debates are about. Choices about port investment, naval-force posture, sanctions enforcement, and industrial strategy all interact with the shipping infrastructure. Engaging the substrate honestly is more useful than treating trade as an abstract category.
