
That's the simple idea at the heart of the warning from John Beddington, the UK government's chief scientific adviser, of a possible crisis in 2030.
Specifically, he points to research indicating that by 2030 "a whole series of events come together":
* The world's population will rise from 6bn to 8bn (33%)
* Demand for food will increase by 50%
* Demand for water will increase by 30%
* Demand for energy will increase by 50%
He foresees each problem combining to create a "perfect storm" in which the whole is bigger, and more serious, than the sum of its parts.