No, not petrol, my dear American readers, but helium.
Robert Page is product manager for bulk gases at Air Liquide, which supplies gas to industrial firms. He notes his company has not yet been forced to turn away customers. However, he warns that helium — just like natural gas — is a non-renewable resource and one that is quickly dwindling.
Stephen Hawking has said that man must colonize space or face extinction. Long before extinction, though, he will have used up the resources that make technological civilisation possible. And run out of party balloons, it seems.