Sitting on the desk in front of me are a set of graphs. The horizontal axis of each graph is identical: it represents time, from the years 1750 to 2000. The graphs show, variously, human population levels, CO2 concentration in the atmosphere, exploitation of fisheries, destruction of tropical forests, paper consumption, number of motor vehicles, water use, the rate of species extinction and the totality of the gross domestic product of the human economy.

What grips me about these graphs (and graphs don’t usually grip me) is that though they all show very different things, they have an almost identical shape. A line begins on the left of the page, rising gradually as it moves to the right. Then, in the last inch or so - around the year 1950 - it suddenly veers steeply upwards, like a pilot banking after a cliff has suddenly appeared from what he thought was an empty bank of cloud.

The root cause of all these trends is the same: a rapacious human economy which is bringing the world very swiftly to the brink of chaos. We know this; some of us even attempt to stop it happening. Yet all of these trends continue to get rapidly worse, and there is no sign of that changing soon. What these graphs make clear better than anything else is the cold reality: there is a serious crash on the way.