Even More Severe Than the 1973 Oil Embargo! Daily Supply Loss from Iran War Exceeds 14 Million Barrels, Far Surpassing the Three Major Historical Crises

According to calculations by Reuters based on data from the International Energy Agency (IEA), OPEC, and the U.S. Department of Energy (IEA), the Iran war has resulted in the largest recorded single-day crude oil supply shock in history. However, in terms of cumulative supply losses, the 1979 Iranian Revolution remains the worst oil crisis in history.

The current war between the United States, Israel, and Iran has once again prompted the market to draw comparisons with the 1973 Arab oil embargo, the 1979 Iranian Revolution, and the 1991 Gulf War. However, this round of shocks has impacted not only crude oil but also disrupted the supply of natural gas, refined oil products, and fertilizers, highlighting the profound changes in the structure of global energy trade over the past decades.

A Different Kind of Energy Shock

Compared with previous oil crises in history, the scope of the supply shock during the current Iran war is broader.

Past oil crises were mainly centered around disruptions in crude oil supply, whereas this crisis simultaneously affects crude oil, natural gas, refined fuels, and fertilizer supplies. This exposes the vulnerabilities arising from ever-growing global energy demand, highly globalized trade chains, and the increasing importance of the Middle East in supplying refined oil products.

The oil shocks of the 1970s left a profound scar on the global economy and reshaped the policy frameworks of major energy-importing countries. In response, the International Energy Agency was established to provide energy security advisories to industrialized countries and coordinate emergency strategic reserves.

In response to the current crisis, the International Energy Agency has already released a record 400 million barrels from strategic reserves to stabilize the market and compensate for the lost supply from the Middle East.

Daily Supply Loss Exceeds 14 Million Barrels, Far Surpassing Past Crises

According to the International Energy Agency, during this crisis, peak supply losses exceeded 14 million barrels per day, equivalent to about 13.6% of this year’s expected global oil demand of 103.3 million barrels per day.

This figure far surpasses major recent energy crises. IEA data show that during the 1973-1974 Arab oil embargo, peak supply losses were 4.5 million barrels per day; during the 1979 Iranian Revolution, 5.6 million barrels per day; during the 1991 Gulf War, 4.3 million barrels per day.

The natural gas market has also suffered a heavy blow. The conflict has resulted in about one-fifth of Qatar’s global liquefied natural gas (LNG) production capacity being idled. In contrast, during the oil crises of the 1970s, global LNG trade was almost negligible, and Qatar did not begin exporting LNG until 1996.

The shock has also spilled over into the refined oil product market. Shutdowns of refineries in the Gulf have led to shortages of diesel and jet fuel. Over the past few decades, large refineries built in the Gulf region have become key suppliers to African, European, and Asian markets.

According to Argus Media estimates, the conflict has removed about 24 million tonnes of LNG supply from Qatar and the UAE. Based on IEA data projecting global LNG trade at 428 million tonnes in 2025, this equals roughly 5.6% of annual global LNG supply.

Cumulative Losses About 1.5 Billion Barrels, Still Below 1979 Iranian Revolution

In terms of duration and cumulative loss, the current crisis has surpassed the 1973 oil embargo and the 1991 Gulf War, but still remains lower than the 1979 Iranian Revolution.

According to an IEA report released May 13, cumulative supply losses for Gulf oil-producing countries had already exceeded 1 billion barrels at that time. If the loss of 14 million barrels per day from May 14 to June 17—the 35-day period of the U.S.-Iran temporary agreement—is added, Reuters calculations indicate the current conflict has already removed about 1.5 billion barrels of oil from the market.

Although the U.S.-Iran temporary agreement has halted the war, supply disruptions are expected to persist for months; the impact on the natural gas sector may even last for years.

By comparison, during the 1979 Iranian Revolution, single-day supply losses were smaller than those in the current crisis but lasted longer, resulting in a higher cumulative impact. The U.S. Department of Energy estimates Iranian crude oil production from 1978 to 1981 averaged a daily decrease of 3.9 million barrels. Based on this, the production loss over three years was about 4.3 billion barrels.

OPEC data show Iranian crude oil production further fell to 1.47 million barrels per day in 1980. Compared to 1978 production levels, cumulative losses in 1979 and 1980 exceeded 2.7 billion barrels, which is still higher than the losses caused by the current crisis to date.

Losses from 1973 Embargo and 1991 Gulf War Were Smaller

During the 1973-1974 Arab oil embargo, oil producers gradually increased cuts to 4.5 million barrels per day over three months. Reuters calculations show that the embargo cumulatively removed approximately 530 million to 650 million barrels of oil from the market, significantly less than the supply disruption caused by the current Iran war.

The 1991 Gulf War resulted in interruptions in oil production for about four months. With a daily average loss of 4.3 million barrels, cumulative supply losses totaled about 516 million barrels—also less than in the current crisis.

Overall, the Iran war has become the biggest single-day supply loss event in energy history, and its impact goes far beyond traditional oil crises, affecting multiple markets including crude oil, LNG, diesel, jet fuel, and fertilizers. However, in terms of cumulative supply loss, the 1979 Iranian Revolution remains the most severe oil crisis in modern energy history.