Type the phrase 'peak oil' into any popular internet search engine, and you will not be short of results to wade through.
Like the fuel itself, the topic generates a lot of heat and hot air. This week on One Planet, reporter Richard Hollingham seeks to define the term 'peak oil' before asking leading experts whether they believe the event is nearing.
We then sit down with the world's number one energy analyst Fatih Birol. He is chief economist at the International Energy Agency, and advises countries from America to Japan on energy policy. There is plenty we need to ask him about - from the Deepwater Horizon disaster, to drilling off the coast of Greenland, to recent claims that China is now the world's largest energy consumer.... Oh, and what does he think about peak oil?
Listen again to the programme here: