The oil secret was discovered in July, 2008

However, Sadad al-Husseini, a geologist and former head of exploration at the Saudi oil monopoly Aramco, met the US consul general in Riyadh in November 2007 and told the US diplomat that Aramco's 12.5m barrel-a-day capacity needed to keep a lid on prices could not be reached.

According to the cables, which date between 2007-09, Husseini said Saudi Arabia might reach an output of 12m barrels a day in 10 years but before then – possibly as early as 2012 – global oil production would have hit its highest point. This crunch point is known as "peak oil".

From a Wikileak story.