A new analysis by international researchers shows that a prolonged closure of the Strait of Hormuz could have significant consequences for global trade and energy supply. The study finds that not only the volume of trade at risk is critical, but also the duration of any disruption.

The study, “When the Strait Closes: Trade Dependencies and Shipping Disruption Scenarios for the Strait of Hormuz,” was conducted by the Supply Chain Intelligence Institute Austria, the Complexity Science Hub Vienna, and TU Delft.

Massive trade volumes at risk

The Strait of Hormuz is one of the most important maritime chokepoints in the world. Around 20% of global oil shipments pass through the narrow waterway between Iran and Oman.

The analysis shows that annual trade flows worth around USD 1.2 trillion from five Gulf countries (Iran, the United Arab Emirates, Qatar, Kuwait, and Bahrain) could be affected by a prolonged closure.

Most of these trade flows consist of energy products—crude oil, liquefied natural gas (LNG), and refined petroleum products—which together account for roughly USD 800 billion of the affected trade.

Duration of disruption is crucial

Using an agent-based maritime transport model, the researchers simulated different blockage scenarios for the strait.

The key finding: the duration of the disruption is the decisive factor.

• Up to two weeks: economic effects likely limited
• Around one month: noticeable disruptions in global shipping
• More than four weeks: disproportionately increasing impacts due to cascading effects in global supply chains

Delays affecting individual ships can propagate across multiple transport chains, causing congestion at ports and delays in international trade.

Europe moderately affected overall

The European Union imports around USD 47 billion annually from the Gulf countries analyzed in the study.

The countries most exposed include:

• Italy: about USD 9.8 billion per year, mainly LNG imports from Qatar
• Belgium: a major European gas and trading hub
• France, Germany, and the Netherlands: moderate levels of import dependence

The United Kingdom imports approximately USD 13 billion per year from these Gulf exporters.

Austria mainly indirectly affected

“For Austria, our analysis shows only very limited direct trade dependence on imports from the affected Gulf countries—around USD 0.3 billion per year. However, indirect effects through rising energy prices in Europe could be more relevant, since European energy markets are highly interconnected and price shocks can quickly spread across borders,” says Stefan Thurner, President of the Complexity Science Hub and co-author of the study.

Indirect price effects likely

The study concludes that short-term disruptions would mainly trigger price volatility.

Actual supply shortages would only become likely in the case of disruptions lasting several months. In such a scenario, rising energy prices and higher production costs could weaken the competitiveness of European industries.

Policy recommendations

“Our analysis highlights three key priorities for policymakers: First, every effort should be made to end potential blockades as quickly as possible to prevent cascading effects in global supply chains. Second, governments should prepare for longer disruptions, particularly in the energy sector. Third, clear and transparent communication is essential to avoid market panic and hoarding behavior,” Thurner concludes.