Dr Fatih Birol, chief economist at the International Energy Agency (IEA), says his agency's recent study of 800 oil fields around the world (representing three quarter's of the world's oil reserves) reveal that we are facing a global energy catastrophe even sooner than researchers thought.

The IEA estimates that the decline in oil production in existing fields is now running at 6.7 per cent a year compared to the 3.7 per cent decline it had estimated in 2007, which it now acknowledges to be wrong.

This means the pressure will be on to start using enivonmentally-disastrous tar sands in Canada.

Catastrophic oil shortfalls threaten economic recovery, says world's top energy economist