Dr David Ko is the co-founder of Rethinking Choices, with Richard Busellato. They are experienced hedge fund managers with three decades of investment experience working with pensions and savings institutions. They left the industry to focus now on the ways in which we are all pushing the world beyond its limits, and point out that 'climate change will bankrupt us before it drowns us'. Our economy is not designed for a world with finite limits; an economic model for this needs to be centred on ethics and purpose.