Is the decline of oil in sight?

The idea of "peak oil" – a peak in the amount of oil we can physically extract, followed by an irreversible decline in production – has been around for decades. So far, though, it has never been reached on a global level.

Last month, however, the International Energy Agency (IEA) – a global energy organisation that provides governments with analyses and policy support – announced we may soon reach a different but related value: a peak in the global use of (or "demand for") oil.

The single biggest thing that we...