Everyone reading this has an impact on the planet and its limited resources. Most of western society eats farmed meat, drives polluting cars and owns an unprecedented range of consumer goods. The device you’re using to read this (and the one I’m using to write it), the light on your office desk and the cup of tea sat next to you – they all use energy. Multiply all of this (and lots more) by a global population spiralling towards 9 billion and it’s easy to see why as a species, we have a problem. A big problem.