There are a number of key concepts that are essential for a proper grasp of how to ensure a sustainable future for Spaceship Earth. The hardest for many is ‘exponential growth’ which has been the accelerating feature of the impact of human activity on the planet since the industrial revolution. The impact of the exponential growth of human population + economic productivity and its waste products + debt within the credit-based financial system + technological innovation is threatening the resilience of Spaceship Earth’s life support systems. These exponential (repeatedly doubling) trends produced by the ‘Machine World’ inevitably reach limits on a finite planet. This link –> offers an introduction to the concept of resilience.