Independent (UK): You’ve probably heard the dubious statistic that a glass of tap water in London has cycled through seven different people before ending up in your tumbler. But how much does water cycle naturally around the world? You might also remember those diagrams with lots of arrows in science lessons, showing water cycling between the seas, skies and rivers, but what is the relationship between the global water wheel and our environment? When it comes to the amount of water that trickles, drips …