Parts A and B of the sixth Global Environmental Outlook (GEO- 6) indicate that the current global development trends and their future trajectories are not sustainable. At the same time, nations worldwide have agreed on a set of ambitious goals as part of the United Nations 2030 Agenda for Sustainable Development, including the Sustainable Development Goals (SDGs), a broad range of multilateral environmental agreements and other frameworks. Together, they aim for halting environmental degradation and aim to enable better development pathways that can bene t both humans and the ecosystems that support human well-being. The key questions now are whether future trends would lead to the achievement of these ambitious goals and thereby a more sustainable future – and, if not, what would be required, both in policy and practice, to bend the trend towards positive and sustainable development pathways. Part C of GEO-6 aims to provide an integrated and holistic view of the scienti c information to address these questions. It presents new approaches to developing science-based information for decision makers, by combining scenario-based quantitative projections (de ned here as top-down approaches) with grass- roots and participatory methods (bottom-up) approaches.