Analysis: What happens if Iran closes the Strait of Hormuz?

Arab News

19 hours ago

LONDON: It is thanks to a quirk of ancient geological history that almost half the global oil and gas reserves are located under or around the waters of the Arabian Gulf, and that the flow of the bulk of bounty to the world must pass through the narrow maritime bottleneck that is the Strait of Hormuz.
On Friday, Israeli Prime Minister Benjamin Netanyahu told the world that Israel's unprecedented attack on Iran earlier in the day was an act of self-defense, aimed at disrupting its nuclear program.
By Saturday, Israel had broadened its targets from nuclear facilities, ballistic-missile factories and military commanders to oil facilities in apparent retaliation for waves of missile and drone strikes on its population centers.
In his video broadcast, Netanyahu said: 'We will hit every site and every target of the ayatollahs' regime, and what they have felt so far is nothing compared with what they will be handed in the coming days.'
In a stroke, Israel had escalated the conflict into a crisis with potentially immediate ramifications for all the oil- and gas-producing Gulf states and, in the longer term, for economies of the region and the entire world.
Reports originating from lawmakers in Tehran began to circulate suggesting that Iran was now threatening to close the Strait of Hormuz. Sardar Esmail Kowsari, a member of Iran's parliament and a commander in the Islamic Revolutionary Guard Corps, warned in an interview that closing the waterway 'is under consideration and that Iran will make the best decision with determination.'
While the strait is, in the words of the US Energy Information Administration, 'the world's most important oil transit choke point' — about a fifth of the world's total petroleum liquids consumption passes through it — the two main oil producers, the UAE and Saudi Arabia, are not without alternative routes to world markets for their products.
Saudi Aramco operates twin oil and liquid gas pipelines which can carry up to 7 million barrels a day from Abqaiq on the Gulf to Yanbu on the Red Sea coast. Aramco has consistently shown resilience and ability to meet the demands of its clients, even when it was attacked in 2019.
The UAE's onshore oil fields are linked to the port of Fujairah on the Gulf of Oman — beyond the Strait of Hormuz — by a pipeline capable of carrying 1.5 million barrels a day. The pipeline has attracted Iran's attentions before. In 2019, four oil tankers, two each belonging to Saudi Arabia and the UAE, were attacked off the port of Fujairah.
Iran has never fully closed the Strait of Hormuz but it has threatened to do so multiple times in response to geopolitical tensions.
Historically, it has used the threat of closure as a strategic bargaining tool, particularly during periods of heightened conflict. In 2012, for instance, it threatened to block the strait in retaliation for US and European sanctions but did not follow through.
Naturally, disruptions in supplies would cause an enormous increase in energy price and related costs such as insurance and shipping. This would indirectly impact inflation and prices worldwide from the US to Japan.
According to the experts, Iran can employ unmanned drones, such as the Shahed series, to target specific shipping routes or infrastructure in the strait. It may also attempt to use naval vessels to physically obstruct passage through the strait.
Ironically, the one country in the region that would face no direct consequences from a blockade of the Strait of Hormuz is Israel. All of its estimated consumption of 220,000 barrels of crude a day comes via the Mediterranean, from countries including Azerbaijan (exported via the Baku–Tbilisi–Ceyhan pipeline, which runs through Turkiye to the eastern Mediterranean), the US, Brazil, Gabon and Nigeria.
This section contains relevant reference points, placed in (Opinion field)
The capability to disrupt traffic in the Strait of Hormuz is one thing, a full closure is quite another, as it would harm Iran's own economy given that it relies on the waterway for its oil exports.
History teaches that shutting off the flow of oil from the Arabian Gulf is far easier said than achieved. The first country to attempt to prevent oil exports from the Gulf was Britain, which in 1951 blockaded exports from the Abadan refinery at the head of the Gulf in response to the Iranian government's decision to nationalize the country's oil industry.
The motive was purely financial. In 1933 Britain, in the shape of the Anglo-Iranian Oil Co., a forerunner of today's BP, had won a lopsided oil concession from the Iranian government and was reluctant to give it up.
The blockade did not last — impoverished post-war Britain needed Abadan's oil as badly as Iran — but the consequences of Britain's actions are arguably still being felt today.
The very existence of the current Iranian regime is a consequence of the 1953 coup jointly engineered by Britain and the US, which overthrew then Prime Minister Mohammad Mossadegh, architect of the oil nationalization plan, and set Iran on the path to the Islamic Revolution of 1979.
The first modern blockade of oil shipments in the Gulf happened the following year, when Saddam Hussein, hoping to take advantage of the disruption caused by the revolution and the ousting of the shah, attacked Iran, triggering the disastrous eight-year Iran-Iraq War.
Still equipped with the shah's US-supplied and trained air force and navy, Iran's first reaction was successfully to blockade Iraqi warships and oil tankers in Umm Qasr, Iraq's only deep-water seaport.
Iraqi aircraft began attacking Iranian shipping in the Gulf, provoking an Iranian response that focused initially on neutral ships bringing supplies to Iraq via Kuwait, a development that soon escalated into attacks by both sides on shipping of all flags.
The first tanker to be hit was a Turkish ship bombed by Iraqi aircraft on May 30, 1982, while loading at Iran's Kharg Island oil terminal. The first to be declared a total loss was a Greek tanker, struck by an Iraqi Exocet missile on Dec. 18, 1982.
In terms of lives lost and ships damaged or destroyed, the so-called Tanker War was an extremely costly episode, which caused a temporary sharp rise in oil prices. By the time it ended in 1987, more than 450 ships from 15 countries had been attacked, two-thirds of them by Iraq, and 400 crew members of many nationalities had been killed.
Among the dead were 37 American sailors. On May 17, 1987, American frigate the USS Stark, patrolling in the Gulf midway between Qatar and the Iranian coast, was hit by two Exocet missiles fired by an Iraqi Mirage jet.
But at no point throughout the Tanker War was the flow of oil out through the Strait of Hormuz seriously disrupted.
'Iran couldn't fully close the strait even in the 1980s,' said Sir John Jenkins, former UK ambassador to Saudi Arabia and Iraq.
'It's true that in those days the UK and others had a significant mine-sweeping capacity, which we lack today. But even if Iran laid mines again or interfered with shipping in the strait in other ways it will almost certainly draw in US maritime forces from the 5th Fleet (based in Bahrain) and perhaps air assets too.
'Also, attempting to close Hormuz will hit their own significant illegal oil trade.'
Regardless, the Iranians 'will be very tempted to do this. But it is a delicate calculation — doing enough to get Russia and in particular China involved in support of de-escalation but not enough to provoke US action, effectively on the side of Israel,' Jenkins said.
In an analysis published in February last year, following an uptick in maritime aggression by Iran in and around the Strait of Hormuz, the Center for Security Policy, a Washington think tank, concluded that because 76 percent of the crude oil that passes through it is destined for Asian markets, 'as one of Tehran's sole remaining allies, it would not be in China's best interest for the strait to fully close.'
Lessons learned during the 1980s Tanker War are relevant today. In the wake of that conflict, an analysis by the Strauss Center for International Security and Law offered a cool-headed assessment of the vulnerability of the Strait of Hormuz to any attempt at enforced closure by Iran.
'Our research and analysis reveals significant limits to Iran's ability to materially reduce the flow of oil through the Strait of Hormuz for a sustained period of time,' the report, published in 2008, said.
'We find that a large-scale Iranian campaign would yield about a 5 percent chance of stopping each tanker's transit with small boat suicide attacks and a roughly 12 percent chance of stopping each tanker's transit with volleys of anti-ship cruise missiles.'
Initially, the Tanker War led to a 25 percent drop in commercial shipping and a temporary sharp rise in insurance premiums and the price of crude oil.
'But the Tanker War did not significantly disrupt oil shipments … Even at its most intense point, it failed to disrupt more than 2 percent of ships passing through the Gulf,' the report said.
The bottom line, it said, 'is that if a disruption to oil flows were to occur, the world oil market retains built in mechanisms to assuage initial effects. And since the long-term disruption of the strait, according to our campaign analysis, is highly improbable, assuaging initial effects might be all we need.
'Panic, therefore, is unnecessary.'
Israel's critics say it already has much to answer for in unleashing its unilateral assault on Iran. Netanyahu has been claiming for years that Iran was 'only months away' from producing a nuclear weapon and his claim that that is the case now has no more credibility than before.
'Benjamin Netanyahu has started a war with Iran that has no justification,' said Justin Logan, director of defense and foreign policy at Washington think tank the Cato Institute.
Friday's opening attacks overtook US President Donald Trump's statement earlier that same day that 'the United States is committed to a diplomatic resolution to the Iran nuclear issue.'
'Iran was not on the precipice of acquiring nuclear weapons,' Logan said. 'It had not thrown out IAEA inspectors, from whom all information about the Iran nuclear program flowed. It had not enriched uranium to weapons-grade.'
Netanyahu's true motives in launching his attack at this time are not hard for political observers to divine.
He has successfully derailed US-Iranian nuclear talks — ongoing negotiations, due to have been continued on Sunday in Oman, were canceled.
The attack has also caused the postponement of the three-day joint Saudi-French Gaza peace summit at the UN, which had been due to begin on Tuesday, with the issue of Palestinian sovereignty high on the agenda — anathema to Netanyahu's right-wing, anti-two-state government.
'Israel has the right to choose its own foreign policy,' Logan said.
But 'at the same time, it has the responsibility to bear the costs of that policy.'