In early 1994, the International Energy Agency released a statistic that attracted little attention but years later would transform oil markets and the global economy. China, the west's energy watchdog said at the time, had just become “a net importer of oil on an annual basis for the first time since the 1960s”.

The consequences became obvious as China's voracious energy needs propelled the country towards its current ranking as the world's second-largest oil importer, behind only the US – in the process pushing crude prices to a record high of nearly $150 a barrel in 2008. Beijing, which in 1993 imported a mere 30,000 barrels a day, about as much as Ireland does now, is these days buying 5m barrels a day – or the combined production of Kuwait and Venezuela.

Commodities analysts and executives say the shift in 1993 was an example of a “China moment” – what happens when the world's most populous country moves from being an exporter to a net importer of a particular resource (or vice versa in the case of finished goods).