Chapter 1 summarises our best knowledge about the predicted future of global warming and its potentially catastrophic implications for human habitats and human wellbeing. The policy options are summarised, divided between programmes to mitigate climate change and to adapt to it. But climate policy alone could be unjust and inequitable. The goal must be to respect biophysical boundaries while at the same time pursuing sustainable wellbeing: that is, wellbeing for all current peoples as well as for future generations. This means paying attention to its distribution between peoples, and to issues of equity and social justice. Between an upper boundary set by biophysical limits and a lower boundary set by decent levels of wellbeing for all today lies a safe and just space for humanity. The chapter concludes by noting two global landmarks in 2015: the UN Sustainable Development Goals (SDGs) and the Paris climate agreement. Together they reveal a yawning gap between what is needed for a safe climate and the prospects for a just and flourishing society.