guardian.co.uk: As I approach my 72nd birthday, I have reluctantly achieved the position of elder, and it is mindboggling to reflect on the changes that have occurred in my lifetime. The population of the world has tripled, while technology has exploded from early radio, telephones and propeller planes to the telecommunication revolution, computers, space travel, genetic engineering and oral contraceptives. And stuff! My biggest challenge is to staunch the flow of stuff into my life. But these great successes – economic growth, technology, consumer goods – have come at enormous cost: the degradation of our very life support systems – air, water, soil, energy and biodiversity.

We are now the most numerous species of mammal on Earth and each of the 6.6 billion of us must breathe, drink, eat, be clothed and find shelter. So the mere act of living means our species has a heavy collective ecological footprint. When that is amplified by technology (computers, TV, cars, etc) used on our behalf, our hyperconsumption and the global economy, we have been transformed into a force that is now altering the biological, chemical and physical features of the planet on a geological scale. [ read more ]