In 1982, the United States began building a strategic petroleum reserve meant to insulate drivers in Ohio and factories in Michigan from the next oil shock. Today, according to recent reports, that reserve sits at its lowest level since the year it was created. It is a small, specific fact that captures a much larger warning issued this week by the International Monetary Fund in Bangkok: the buffers that once protected the world economy from chaos in the Middle East are running out. In its twice-yearly World Economic Outlook, published as finance ministers and central bankers gathered for the IMF and World Bank's annual meetings, the Fund credited quick thinking for a crisis so far avoided.

Oil shipments were rerouted around the Strait of Hormuz after the US-Iran conflict threatened to choke off a route through which roughly a fifth of the world's oil passes, and governments released strategic stocks to keep prices from spiking. Global growth, as a result, is now forecast at 3.1% this year, a slight upgrade from July's 3% estimate. Yet the IMF's economic counsellor, Silvana Tenreyro, made clear that resilience should not be mistaken for safety.

The concern now is what happens if another shock arrives before anyone has restocked the shelves. The International Energy Agency has already carried out record emergency oil releases this year and pledged to move faster after a ministerial meeting last month. But with many governments already burdened by high debt, there may be little fiscal room left to cushion consumers against a sudden jump in petrol or diesel prices — a vulnerability underscored by Donald Trump's recent deal with Vladimir Putin to briefly ease sanctions on Russian diesel imports, a move analysts doubt will meaningfully lower pump prices. Kristalina Georgieva, the IMF's managing director, put the choice to policymakers bluntly ahead of the Bangkok meetings.