While the main threats to humankind today are the consequences of the human aptitude for culture, our only hope for overcoming them lies in in this aptitude. This booklet shows how human culture has emerged as a new kind of force, and a very powerful one, in human ecosystems. It describes how the worldviews of the prevailing cultures across the globe today are leading to human activities on a scale, and of a kind, that are causing irreparable damage to the living systems on which we depend. If present conditions continue unabated, the collapse of civilisation is inevitable. There will be no effective shift to sustainability unless these cultures undergo radical transformation. The author argues that that this cultural transformation will not happen unless a wave of new understanding sweeps across the cultures of the world - understanding of life on Earth and of the human place in nature. We can think of the kind of cultural change we need as a biorenaissance: a rebirth in the way we relate to nature, to create a society that lives in harmony with the laws of nature, and ourselves as part of nature.