It's simple. If we can't change our economic system, our number's up

It's the great taboo of our age – and the inability to discuss the pursuit of perpetual growth will prove humanity's undoing

George Monbiot
The Guardian, Tuesday 27 May 2014 13.38 EDT

Let us imagine that in 3030BC the total possessions of the people of Egypt filled one cubic metre. Let us propose that these possessions grew by 4.5% a year. How big would that stash have been by the Battle of Actium in 30BC? This is the calculation performed by the investment banker Jeremy Grantham.

Go on, take a guess. Ten times the size of the pyramids? All the sand in the Sahara? The Atlantic ocean? The volume of the planet? A little more? It's 2.5 billion billion solar systems. It does not take you long, pondering this outcome, to reach the paradoxical position that salvation lies in collapse.