Overview
The International Energy Agency (IEA) described the closure of the Strait of Hormuz as the largest disruption to global oil markets on record, with supply set to decline by about 8 million barrels per day in March, equal to roughly 8 percent of global output. In response, IEA member countries committed to a historic coordinated release of 400 million barrels from strategic stockpiles to help stabilise prices and offset lost Middle East production.
Why the disruption is historically significant
The scale of the current supply loss, as measured in millions of barrels per day and as a share of global production, has prompted emergency measures from consuming nations. The IEA action to draw down 400 million barrels from strategic reserves is unprecedented in size for the organisation, reflecting the magnitude of the supply shortfall caused by the Strait of Hormuz closure.
A survey of major past oil supply disruptions
The following events outline earlier episodes when oil availability was sharply curtailed. Each entry summarises the nature of the disruption, the quantitative impact on supply where provided, market reactions and material policy responses noted at the time.
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The 1973-1974 Arab oil embargo
The embargo was triggered by the Yom Kippur War, which began on October 6, 1973, when Egypt and Syria launched coordinated attacks on Israel. Arab producers acting through the Organization of Arab Petroleum Exporting Countries implemented an immediate 5 percent production cut, followed by further 5 percent monthly reductions. The measures aimed to pressure Western states to press Israel to withdraw from territories occupied since the 1967 Six-Day War.
Declassified U.S. National Security Council documents prepared for President Richard Nixon estimated that the embargo would leave the United States short by 2 to 3 million barrels per day, while the total shortfall across embargoed nations was estimated at around 4.5 million barrels per day. OAPEC announced the embargo on October 17, 1973, and U.S. government records indicate it remained in place against the United States until March 1974.
Crude prices nearly quadrupled in the period, moving from about $2.90 per barrel before the embargo to $11.65 by January 1974. The U.S. government prepared fuel rationing plans, directed industries to convert from oil to coal where feasible, pushed for greater domestic production and advanced emergency energy legislation. The crisis led consuming nations to establish the International Energy Agency in 1974 to coordinate responses to future supply shocks.
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The 1978-1979 Iranian revolution
Political upheaval in Iran culminated in the collapse of Shah Mohammad Reza Pahlavi’s government and the rise of Ayatollah Khomeini. Iranian oil production fell sharply, declining by 4.8 million barrels per day by January 1979, equivalent to about 7 percent of global supply. Oil prices began rising rapidly in mid-1979 and more than doubled between April 1979 and April 1980, driven by fears of further disruption, speculative hoarding and strong global demand.
The price surge contributed to rising inflation in the United States. In August 1979, Paul Volcker was appointed chairman of the Federal Reserve and the central bank adopted aggressive monetary tightening to rein in inflation. Those policies, combined with the oil shock, pushed the U.S. economy into a severe recession.
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The 1990-1991 Gulf crisis
Iraq’s invasion of Kuwait and the ensuing United Nations embargo on Iraqi and Kuwaiti oil removed about 4.3 million barrels per day from global markets. Before the conflict, Iraq produced about 3.1 million barrels per day and exported 2.7 million, while Kuwait produced about 1.8 million and exported 1.7 million. Together those figures accounted for nearly a third of Gulf oil output and exports.
Oil prices surged, with Brent crude rising from about $17 per barrel in July 1990 to around $36 by October 1990, before easing after the war ended in February 1991. The IEA activated its Co-ordinated Energy Emergency Response Contingency Plan and prepared measures to make 2.5 million barrels per day available to markets within 15 days. That package included 2 million barrels per day from emergency stock releases, 400,000 barrels per day from demand restraint measures and 100,000 barrels per day from fuel switching and spare production capacity.
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Hurricanes Katrina and Rita in 2005
In August 2005 Hurricane Katrina struck the U.S. Gulf Coast, shutting in substantial offshore production. At the disruption peak on August 29, 2005, about 1.38 million barrels per day of oil production was shut in, according to U.S. government data. Production losses declined over time but were still about 840,000 barrels per day by September 16, 2005.
Hurricane Rita followed in September, and combined storm-related outages reached up to 1.53 million barrels per day at the peak on September 26, 2005. The U.S. Department of Energy loaned 9.1 million barrels of crude from the Strategic Petroleum Reserve to refineries, and the United States joined a 30 million barrel coordinated release with the International Energy Agency. Regulators issued emergency waivers to allow the temporary use of winter-blend gasoline, higher sulfur diesel fuel and they temporarily waived the Jones Act to permit foreign vessels to transport fuel between U.S. ports in order to ease bottlenecks.
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The 2022 Russian invasion of Ukraine
Russia’s full-scale invasion of Ukraine in 2022 triggered a global energy crisis as European nations and other buyers sought to reduce dependence on Russian oil and gas. Prices spiked over 50 percent within a few weeks, with crude reaching some of its highest levels since 2008 as markets raced to find alternative supplies.
In March 2022, then-President Joe Biden ordered the release of 180 million barrels over six months to help combat the price spike. The United States and other Western nations also implemented price caps on Russian oil exports in an attempt to limit Russian revenue from oil while keeping supplies available in world markets.
Summary
Historical episodes described above demonstrate how geopolitical conflict, political transformation within major producers and extreme weather have each produced sudden and material reductions in oil supply, prompting market upheaval and coordinated policy responses. The IEA has characterised the current closure of the Strait of Hormuz as the largest such shock to date, with a projected fall in supply of about 8 million barrels per day and a record 400 million barrel strategic release to cushion markets.
Key points
- Supply impact - The IEA estimates the current closure of the Strait of Hormuz will reduce supply by about 8 million barrels per day in March, roughly 8 percent of global output.
- Coordinated response - IEA member countries agreed to release 400 million barrels from strategic stockpiles, the largest coordinated release reported by the agency for this type of shock.
- Market precedent - Past disruptions have removed between roughly 1.38 million and 4.8 million barrels per day from markets at their peaks and led to price surges, policy interventions and emergency stock releases.
Risks and uncertainties
- Price volatility risk - Historical episodes documented here show that supply interruptions have produced sharp price increases, which in turn have affected inflation and economic activity.
- Refining and transport constraints - Past emergencies have generated bottlenecks at refineries and required regulatory waivers, loans from strategic reserves and emergency shipments to keep fuels flowing to consumers and industry.
- Macroeconomic impact - Large oil shocks have contributed to higher inflation and, in combination with responding monetary policy, have been associated with economic recessions.
Conclusion
Past supply shocks provide a set of concrete examples of how sudden losses of oil production translate into higher prices, policy interventions and economic strains. The IEA’s description of the Strait of Hormuz closure as the largest disruption in history underlines the scale of the current event and explains the unprecedented collective decision to draw down strategic stockpiles.