The International Energy Agency's March Oil Market Report declared the Iran war "the largest supply disruption in the history of the global oil market" — a designation the agency has never previously applied to any conflict, embargo, or natural disaster in its five decades of operation. Gulf production is down at least 10 million barrels per day. Hormuz flows have fallen from 20 million bpd to what the IEA described as "a trickle." Global supply will drop 8 million bpd this month, the agency projects.
The historical comparisons are arithmetic, not analogy. The 1973 Arab Oil Embargo — the standard benchmark for energy supply shocks — removed roughly 5 million bpd and took months to reach full effect as existing contracts expired and inventories drew down. The 1979 Iranian Revolution removed approximately 3.9 million bpd. The 1990 Iraqi invasion of Kuwait took roughly 4.3 million bpd offline. This war has doubled the 1973 figure in a fortnight. Combining any two of those historical disruptions still falls short of the current loss.
The IEA's own countermeasure — the 400-million-barrel coordinated reserve release, the largest in the agency's history — has already been overtaken by events. The reserves are designed to flow over months; the supply gap opened in days. The International Maritime Organisation's cumulative figures confirm the scale in operational terms: tanker traffic through Hormuz is down 90% from pre-war levels, with 20,000 seafarers stranded in the Persian Gulf. Every major Protection and Indemnity club has cancelled War risk coverage. Without insurance, commercial vessels cannot legally sail.
The IEA's aggregate figure also obscures a structural asymmetry. TankerTrackers.com co-founder Samir Madani documented 11.7 million barrels of Iranian crude transiting Hormuz since 28 February, all bound for China, with shadow fleet ships accounting for half of all March transits. Chinese-operated vessels systematically broadcast AIS messages emphasising Chinese ownership and crew composition. The blockade does not remove all oil from the market — it removes non-Iranian, non-Chinese oil. Iran decides who transits and who does not, converting the world's most important chokepoint into a tool of selective Economic warfare that rewards Beijing's diplomatic cover with discounted supply while the rest of the market absorbs the full disruption.
