How much oil is left?

Not for nothing do they call it ‘black gold’. Oil – or to be more accurate, petroleum – is the fuel which powers the modern world. Not only is it used to make the gasoline which keeps many millions of vehicles on the road and planes in the air, it is also used in the manufacture of hundreds of other products, from kerosene to asphalt to plastics: even some pharmaceuticals.

The word petroleum was coined from the Latin terms for ‘rock oil’ and that is a pretty good description of its origins. Vast quantities of organic residue – principally from prehistoric zooplankton and algae – are trapped beneath sedimentary rock: an enormous, all-natural pressure cooker. When it first flows out of the ground – sometimes spontaneously – the substances is often referred to as ‘crude oil’. A complex process of refining and distillation then turns dark, dense and pungent crude into all those valuable derivatives.

Our civilization is deeply in love with oil. We just can’t get enough, burning through a staggering 95 million barrels of the stuff a day. It has been the source of fantastic fortunes.

But just how long can we keep this up? Oil is, after all, the ultimate non-renewable resource. How much oil is left down there for us to consume so recklessly?

This crucial question has been hotly debated for decades. Crude oil discoveries have continued and production has actually risen despite dire predictions in decades past, meaning the date of maximum extraction followed by decline – so called ‘peak oil’ -has had to be repeatedly postponed.

But a precise answer is difficult. Experts disagree on how to calculate the amount of oil remaining in the various reservoirs around the world. According to a much cited estimate by BP, the world has another 53 years of oil to burn through. That could prove a problem for our grandchildren, but is comfortably far enough away for most of us to put out of our minds.

However, this estimate is based on currently identified sources of crude – so-called ‘proved reserves’ and current extraction technology. If new sources are found in the future and production continues to climb, peak oil may remain fuzzy and hard to pin down. As recently as last November, the US Geological Survey announced the discovery of the largest new oil reservoir in the whole of the United States: in Texas.

Increasingly such discoveries are the exception rather than the rule though: the amount of money spent on oil discovery and development has fallen to the lowest level in decades. Offshore oil discoveries are in particular decline.

So the question remains open. But one thing is certain: we will have to break our addiction to oil sooner or later, or be forced to go cold turkey when the last well finally runs dry.