Starting with a motley group of businessmen, academics and scientists meeting in Rome in the 1960s, Ian Johnson looks at how the Club of Rome has influenced global thinking about sustainable development.
Crispin Tickell surveys the rampant rise of human population - from being a species to a geological period - and wonders if our size will eventually be our ultimate undoing.
As the world population increases and moves into cities, our human settlements may endanger the poor or present the solutions for sustainability. Diane Diacon explains that we have the solutions but we need to start applying them.