The recent US-Iran conflict triggered the largest-ever daily disruption to global oil supplies, surpassing previous crises such as the 1973 Arab oil embargo and the 1991 Gulf War in terms of peak production losses. The 1979 Iranian Revolution, however, remains the most severe oil shock in history when measured by cumulative supply losses, according to Reuters calculations based on data from the International Energy Agency (IEA), OPEC and the US Department of Energy.
Biggest daily supply disruption in history
According to the IEA, the 35-day US-Iran conflict disrupted more than 14 million barrels of oil per day (bpd) at its peak, accounting for nearly 13.6% of projected global oil demand of 103.3 million bpd this year. Reuters calculations show this far exceeded previous oil shocks, including:
1973-74 Arab oil embargo: 4.5 million bpd
1979 Iranian Revolution: 5.6 million bpd
1991 Gulf War: 4.3 million bpd
Unlike previous crises, the latest conflict simultaneously disrupted crude oil, liquefied natural gas (LNG), refined fuels and fertiliser supplies, exposing vulnerabilities in global energy markets.
Iran War Oil Shock vs History’s Biggest Crises
Reuters calculations based on IEA, OPEC and U.S. Department of Energy data
WHAT’S DIFFERENT
Not just an oil shock
Unlike the crises of the 1970s and 90s, the Iran war has hit crude oil, natural gas, refined fuels and fertiliser supplies at once — exposing risks built up over decades of rising demand, globalised trade and the Gulf’s growing role as a finished-fuel supplier.
1
Crude oil disrupted
Peak losses exceeded 14 million bpd, the largest daily supply loss on record.
2
Natural gas hit too
Roughly one-fifth of global LNG production in Qatar was shut in — a market that barely existed during the 1970s shocks.
3
Refined fuels squeezed
Gulf refinery outages contributed to shortages of diesel and jet fuel, rippling into Africa, Europe and Asia.
RECORD RESPONSE
400 million barrels released
The IEA released a record 400 million barrels from strategic reserves to stabilise markets and offset lost Middle Eastern supply.
14M+ bpd
Iran War Peak Loss
13.6%
Of Global Demand (103.3M bpd)
Crisis
Peak Daily Loss
Iran War (2026)
14M+ bpd
Iranian Revolution (1979)
5.6M bpd
Arab Oil Embargo (1973–74)
4.5M bpd
Gulf War (1991)
4.3M bpd
By peak daily loss, the Iran war is the largest oil supply shock on record — more than double the 1979 Iranian Revolution.
Crisis
Cumulative Loss
Iran War (35 days to Jun 17 deal)
~1.5B barrels
Iranian Revolution (1978–81)
~4.3B barrels
Iranian Revolution (1979–80 only)
~2.7B barrels
Arab Oil Embargo (1973–74)
530–650M barrels
Gulf War (1991)
~516M barrels
Figures are Reuters calculations based on IEA, OPEC and U.S. Department of Energy data; some estimates are partially offset by increased output elsewhere in the Gulf.
STILL THE RECORD HOLDER
1979 remains the biggest oil crisis by total barrels lost
Despite the Iran war’s unprecedented daily losses, the Iranian Revolution’s longer duration means it still holds the record for cumulative supply loss — and disruption from the current conflict is expected to continue for months, and potentially years for gas.
~1/5
Qatar LNG Output Shut In
24M
Metric Tons LNG Lost (Qatar + UAE)
5.6%
Of 2025 Global LNG Trade
NO PRECEDENT IN THE 1970S
A gas shock the old crises never faced
During the 1970s oil shocks, LNG trade was negligible — Qatar didn’t begin exports until 1996. That makes the current gas disruption, layered on top of record oil losses, unlike anything in prior energy crises.
Why 1979 still remains the biggest oil crisis
Despite recording the highest daily disruption, the current conflict has not yet surpassed the cumulative losses caused by the Iranian Revolution. Reuters estimates suggest the ongoing conflict has removed roughly 1.5 billion barrels of oil from global markets so far.
By comparison, the US Department of Energy estimates Iran’s oil production fell by an average of 3.9 million barrels per day between 1978 and 1981, translating to approximately 4.3 billion barrels of lost production over three years. Even considering only 1979 and 1980, Reuters calculations indicate cumulative losses exceeded 2.7 billion barrels, significantly higher than those recorded during the present conflict.
LNG and fuel markets also hit
The disruption extended well beyond crude oil. The conflict temporarily shut down around one-fifth of Qatar’s LNG production, while refinery outages across the Gulf contributed to shortages of diesel and aviation fuel.
According to energy consultancy Argus Media, nearly 24 million metric tonnes of LNG supply from Qatar and the UAE were affected, representing roughly 5.6% of annual global LNG trade.
To stabilise global markets, the International Energy Agency released a record 400 million barrels from strategic petroleum reserves. The agency said the coordinated release was aimed at offsetting supply disruptions from the Middle East and preventing sharper spikes in energy prices.
How India managed Iran war energy crisis
The 1979 Iranian Revolution caused global crude prices to more than double from around $13 to over $34 per barrel. Then India, which was heavily reliant on oil imports from Iran, managed this crisis through a combination of aggressive state-backed structural shifts, diplomatic maneuvering, and domestic conservation.
On Saturday, speaking after inaugurating a refinery in Rajasthan’s Pachpadra and launching multiple development projects, Prime Minister Narendra Modi shared that India managed the current energy crisis through proactive planning and diplomatic engagement.
“When the crisis began, India was importing energy from about 25-26 countries. During the crisis, we increased this to more than 40 countries,” PM Modi said, crediting India’s diplomatic outreach for ensuring uninterrupted energy supplies.
Government absorbed fuel price shock
PM Modi said the government took several measures to shield consumers from rising global oil prices. According to the Prime Minister, public sector oil companies incurred losses exceeding Rs 75,000 crore between April and June due to elevated international crude prices.
“We reduced excise duty by Rs 10 per litre and ensured that the burden on citizens did not increase significantly,” he said.
The Prime Minister also criticised those who had predicted India would struggle during the crisis. “Rumours were spread, and people were incited, but those with malicious intentions did not succeed. Those who wished to see India fail had even begun making predictions. Today, they must be wallowing in the depths of despair,” PM Modi said.
India’s refining capacity continues to expand
Noting the country’s growing role in the global energy sector, PM Modi said India has become the world’s fourth-largest refining hub and continues to expand its refining capacity through new infrastructure projects.
His remarks come as India continues to diversify crude imports, strengthen refining capabilities and reduce vulnerability to geopolitical disruptions in global energy markets. While the current US-Iran conflict has produced the largest short-term supply shock on record, historical data compiled shows the 1979 Iranian Revolution remains the benchmark for the most severe oil crisis in terms of total production losses.
