The conflict in Iran has disrupted energy and commodity markets. Iran has effectively closed the narrow strait of Hormuz, a vital oil transit point, attacking more than a dozen ships over the past two weeks that have tried to sail through the waterway.
Authors
- Gokcay Balci
Lecturer in Sustainable Freight Transport and Logistics, University of Leeds
- Ebru Surucu-Balci
Assistant Professor in Circular Supply Chains, University of Bradford
Donald Trump has been pressing US allies in Europe to help secure the strait, warning on March 15 that it will be "very bad for the future of Nato" if they do not support American efforts to reopen Hormuz. But Iran has vowed to keep the waterway closed.
The disruption to Gulf shipping has caused Brent crude oil prices to jump sharply from around US$70 (£53) a barrel before the crisis began to more than US$100 . Global trade in a wide range of other goods - from consumer products to agricultural raw materials - is being affected too.
But the crisis has also highlighted a broader issue: that global trade depends on a surprisingly small number of narrow waterways, which are often called maritime "chokepoints". Here is a guide to the chokepoints that matter most for global trade, and how vulnerable each one is to disruption.
1. Strait of Hormuz
Hormuz is the world's most critical energy chokepoint. Connecting the Persian Gulf to the Arabian Sea, it carries around 39% of the seaborne crude oil trade and 19% of natural gas. Unlike most trade chokepoints, there is no viable alternative to Hormuz for Gulf states to export their energy.
Iran has periodically threatened to close the strait of Hormuz since the 1980s. But the disruption caused to shipping since late February, when the US and Israel first launched airstrikes across Iran, is the most serious escalation in decades. It has caused the largest oil supply disruption in history and soaring global oil prices.
The consequences of the current disruption to Gulf shipping extend beyond energy . The Gulf region handles over 26 million containers annually, with major fertiliser exports passing through here too. Prolonged shipping disruption will therefore have a direct effect on global food production costs.
2. Suez canal
The Suez canal links the Red Sea with the Mediterranean, cutting at least ten days off journey times between Asia and Europe. The waterway handles 10% of global seaborne trade , including 22% of container traffic, 20% of car shipments and 10% of crude oil.
Controlled by Egypt, it is not easily threatened directly. But the waterway is not immune to accidents, as demonstrated by the grounding of the Ever Given container ship in 2021. The vessel blocked the canal for six days, disrupting nearly US$10 billion in trade.
The bigger vulnerability of this chokepoint is the Bab el-Mandeb, the strait at the southern tip of the Red Sea. Attacks on commercial shipping by the Iran-backed Houthi group in Yemen between 2023 and 2025, which it carried out in response to Israel's war against Hamas in Gaza, forced many operators to reroute around Africa.
This cut traffic through the Suez canal from over 26,000 vessels in 2023 to around 13,000 in 2024 . Houthi leaders have recently threatened to resume attacks on commercial shipping in retaliation for the Israeli and US attacks on Iran, warning in official communications that their "fingers are on the trigger".
3. Panama canal
Connecting the Pacific and Atlantic oceans, the Panama canal handles around 2.5% of global seaborne trade - a modest share, but concentrated in high-value and strategic cargo such as containerised goods, cars and grain. The canal carries around 40% of all US containerised shipments, valued at US$270 billion annually.
Its vulnerability stems both from the climate and geopolitics. In 2023 and 2024, severe droughts caused water levels in the canal's freshwater reservoirs to fall sharply, forcing restrictions on vessel numbers and size. Then, in early 2025, Trump threatened to take control of the canal. He cited concerns over the operation of some of its ports by Hutchison, a Hong Kong-based company.
4. Strait of Malacca
The Malacca strait is the busiest shipping lane on Earth. It carries 24% of all global seaborne trade , including 45% of seaborne crude oil and 26% of cars. The waterway is also home to Singapore, which hosts the second-busiest container port in the world.
Malacca is the primary gateway through which China, Japan and South Korea receive their energy imports. Nearly 80% of China's oil imports pass through here, a dependence Beijing calls the "Malacca dilemma" .
Piracy remains a persistent concern, with over 130 incidents reported in the Malacca strait in 2025. But the greater risk is geopolitical. Any escalation in tensions between China and the US or India over maritime dominance in the region could severely disrupt passage through the strait.
Malacca is also exposed to natural disasters , including tsunamis and volcanic activity. The Boxing Day tsunami in 2004, for example, caused significant damage to coastal infrastructure at the strait's southern entrance.
5. Turkish straits
The Turkish straits - the Bosphorus and Dardanelles - are the only sea route between the Black Sea and the Mediterranean. They carry 3% of global seaborne trade. While this share may appear small, it includes around 20% of global wheat exports from Ukraine, Russia and Romania.
At just 700 metres wide at its narrowest point, running through the centre of Istanbul in Turkey, navigation is complex and minor collisions are common. Under the Montreux convention , Turkey controls military access to the straits, a power Ankara has used since Russia's 2022 invasion of Ukraine to restrict the movement of warships while keeping commercial traffic open.
Further escalation in the Black Sea area could disrupt this balance and shake global grain markets. The region's high seismic activity adds another layer of risk.
The current crisis in the strait of Hormuz has thrown into sharp relief just how vulnerable global trade is to disruption due to its reliance on a handful of narrow waterways. But the five waterways mentioned above are not the only trade chokepoints.
There are as many as 24 maritime chokepoints in the world, including other major waterways like the Taiwan, Dover and Bering straits. Each of these waterways are exposed to their own combination of geopolitical tension, climate change, piracy, accidents or natural disasters.
The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.
