The world has nearly burned through its oil safety buffer. That is the warning from top oil executives in London this week. Here is what it means.

Countries and companies keep oil in storage to handle shocks. Think of it as a spare tank. When supply is disrupted, they release stored oil to keep prices stable.

More than 1 billion barrels have been released this year, mainly because of the Middle East crisis. Saudi Aramco CEO Amin Nasser said less than 6 billion barrels of commercial stocks remain, and most of that is not actually usable. Only 10% or less is available, he said.

The International Energy Agency is preparing a 100-million-barrel emergency release to ease diesel prices. But even that needed long negotiations, Nasser said, because stocks are so thin.

Why does it matter? World demand is about 102 million barrels a day. With the buffer nearly gone, any new disruption hits prices directly. Chevron CEO Mike Wirth said the fragile market has raised oil’s price floor.

For ordinary people, thinner buffers mean fuel prices can spike faster when crises hit.