The natural world has a lot to teach us. Above all, it teaches about systems and cycles; that altering one component of a system, however small, can have wider implications within and beyond a given cycle. Human society, the planet and the economy are all systems and are all bound together in intricate relationships. Only when we begin to understand this bigger picture can we tackle the systemic problems facing us. This paper takes a short journey through planetary science to grasp some of the dimensions of those relationships, and poses a series of solutions for affecting the kind of systemic transformation that are urgently needed to ensure the health of the planet and of people. Economic theory (and common sense) explains that when something is valuable, and it is free, its use tends to approach infinity - this explains why trees, biodiversity, freshwater and atmospheric space for carbon are all being used ‘like there is no tomorrow’. It also assumes that when something is exhausted (or too expensive), a substitute is almost certain to be found. Economic theory then takes this substitution concept up to a macro level and thinks of the ‘trade-off’ between environment and economy. The logic is that we can have ‘more environment’ if we are prepared to put up with ‘less economy’, or we can have ‘less environment’ if we want a bigger economy. The traditional economic world view that dominates the political spectrum is based on infinite resources, substitution, and ultimately this trade-off between environment and economy. This paper takes a systemic view of natural capital and the role that it plays in sustaining the human species and our economic system. It begins with a brief journey into planetary science then, taking stock of the solutions being offered by current economic thinking, posit the role of green economy for transforming the current trajectory. It tackles problems not from the perspective of ‘what is politically feasible?’ but from that of ‘what is absolutely necessary?’: what is necessary in order to ensure that the operating system on which we all depend continues to provide people, communities and all economic activity with a safe space in which to exist.