Global oil reserves could last only weeks if fighting between the United States, Israel and Iran resumes in full and the Strait of Hormuz and Bab al-Mandeb are closed, analysts have warned.
Oil prices have risen towards a five-month high as attacks on tankers increase and efforts to end the conflict remain deadlocked. Brent crude rose by more than $2 to $110.85 a barrel on Wednesday.
Iran’s Islamic Revolutionary Guard Corps said two tankers had been “set ablaze” after striking mines at what it described as an illegal crossing point in the Strait of Hormuz. It later claimed to have hit seven more vessels, although Washington dismissed the allegation.
The IRGC said four of the tankers were carrying oil when they were targeted and caught fire overnight.
Global oil reserves have already been heavily depleted
Emergency oil reserves are stockpiles held by governments or companies on their behalf for use during a supply crisis. Members of the International Energy Agency are required to hold at least 90 days of net imports, although China and India are not members.
On March 11, the IEA’s 32 members agreed to release 400 million barrels from emergency supplies after the war began on February 28. The figure was more than twice the amount released after Russia’s full-scale invasion of Ukraine in 2022.
The United States pledged 172.2 million barrels from its Strategic Petroleum Reserve, while Japan committed 79.8 million. The US reserve has since fallen to 283 million barrels, its lowest level since October 1982.
Much of the American oil was lent rather than sold and must eventually be returned, along with additional barrels.
Aaron Kildow, a senior crude oil analyst at Sparta Commodities, estimated that strategic stocks outside China and Iran had fallen by almost 327 million barrels since the end of 2025. The United States, Europe and Japan accounted for about 95 per cent of the reduction, he said.
That leaves roughly 400 million barrels of usable reserves worldwide, excluding China’s stockpile and Gulf reserves that could be inaccessible if Hormuz were completely closed. Nearly half of the available supplies are held in Japan.
Europe has about 76 million uncommitted barrels, although countries including Germany are retaining some stocks for domestic emergencies. “Europe is the real wildcard, both on timing and willingness,” Mr Kildow said.
China holds about 1.13 billion barrels of crude onshore, down from 1.23 billion in late February but still enough for around 80 days of refinery intake. India’s reserves cover only about eight days of imports.
Hormuz closure could cut Middle Eastern exports sharply
Before the war, around 20 million barrels of oil a day passed through the Strait of Hormuz, representing about a fifth of global oil and liquefied natural gas supplies.
Saudi Arabia has increased shipments from its eastern oilfields to the Red Sea port of Yanbu through the East-West Pipeline, bypassing Hormuz. But the pipeline has been targeted in strikes, while tankers travelling south from Yanbu must pass through Bab al-Mandeb.
The Iran-backed Houthis declared a blockade on Saudi shipping in July. Only 373,000 barrels a day of Saudi crude had travelled through Bab al-Mandeb so far this month, the lowest level since February, according to Muyu Xu, a senior crude oil analyst at Kpler.
If both waterways were closed, Gulf producers would be left with a small number of pipelines and a northbound route from Yanbu, Ms Xu said. Middle Eastern crude exports could fall to about 7.5 million barrels a day from 16.8 million, creating a shortfall of roughly 9.3 million barrels a day.
Further attacks on oilfields, terminals and pipelines could make the disruption “even more severe and prolonged”, Ms Xu said.
The reserves could not be released quickly enough to fully replace such a loss. Japanese and South Korean supplies could move relatively rapidly, Mr Kildow said, but United States barrels are staged over three months and Europe’s contribution remains uncertain.
Chris Beauchamp, chief market analyst at IG Group, said the world had been fortunate during the first closure. “The salient feature of March and beyond was how a crisis didn’t actually develop. We got away with it,” he said.
“I don’t think the global economy will be as lucky next time if there is a protracted conflict,” Mr Beauchamp said. “A month or two is all we have.”
The world would not literally run out of oil, but prices would rise until demand fell. Mr Beauchamp said a price of $150 a barrel was “a very distinct possibility”, with the greatest pressure likely to fall on diesel.
The International Energy Agency said diesel was already priced at almost twice the level of crude. Refiners would compete for oil grades that produce more diesel, with the additional cost ultimately passed on to consumers, Mr Kildow said.
Asian importers with limited reserves would be among the first to feel the impact. India and Pakistan are particularly exposed because alternative supplies from West Africa take 25 to 28 days to arrive by sea, compared with about two days from Fujairah in the United Arab Emirates.
Oil producers outside the Gulf could benefit as refiners sought supplies from the United States, Latin America, West Africa and Russia. ExxonMobil, Chevron and Shell all reported stronger earnings during the current period of high oil prices.
