Global infrastructural development towards a sustainability balance

To achieve balance in global sustainable development remains a huge societal and scientific challenge. Coupled social-environmental systems have provided a framework for addressing the challenge in a holistic manner. Within existing concepts, ‘Green-red loop’ theory has illustrated human development and societies’ dependence on local or remote provisional ecosystems, while ‘a safe operating space’ reveals the limits of development from environmental capacity perspective. Based on these concepts, we formulate a nexus of green-red likelihood, resources dependence and environmental capacity, and evaluate the current global socio-environmental interactions. Results show that the current nexus exhibits a complex and polarised pattern worldwide. Within the nexus, we identify two unfavourable links (i.e. likelihood ~ capacity, likelihood ~ dependence) and one favourable link (i.e. dependence ~ capacity) that define future sustainable development. We suggest the rebalancing of the system through four sustainable trajectories which are derived from the current status of the global systems at national scale. Based on these four trajectories, precautions, unintended outcomes and associated responses are discussed. We emphasise that there is no universal sustainable development trajectory perfectly suitable for every country. Instead, each country should identify their current development status first to adopt appropriate strategies for sustainable development within the global context of socio-environmental balancing. The implementation of such balance strategies imposes higher requirements and challenges on more efficient and robust global collaborations and integrated modelling to support decision making, co-operation and coordination.