Our impacts on the Earth system are at such a scale that we have become a geological force. If we are to not just survive but flourish, we urgently need to create robust and practical solutions to a set of interacting global challenges. These challenges span countries, regions, and academic disciplines. For example: the challenge to establish food, water, and energy security for a global population increasing towards 9 billion by the middle of this century; the urgent need to halt the rapid decline in biodiversity; the required sudden decrease of greenhouse gas emissions in order to avoid dangerous climate change. While diverse, the common thread that links these and other challenges is that these are all ultimately a challenge of systems.