Integrated SDG Implementation—How a Cross-Scale (Vertical) and Cross-Regional Nexus Approach Can Complement Cross-Sectoral (Horizontal) Integration

The growing demand for food, energy, and water, the resulting pressure on natural resources and the environment and the persistent lack of human securities in many parts of the world, require new integrated approaches in management and governance. Integration is not only required horizontally across disciplines and sectors, but also vertically across levels, scales and across regions. Implementation of a vertical Nexus Approach is to be achieved through mainstreaming, i.e. through entry points such as national and regional development plans, strategies and policies to which it can add value. In particular, the call for integrated implementation of the SDGs requires a horizontal and vertical Nexus Approach for achieving coherence across sustainability goals and targets across levels, scales and across regions. For example, the “global level of ambitions” to which the 2030 Agenda refers can be specified and quantified with the help of the Planetary Boundaries (PBs). For mainstreaming the PBs into say,—national—policy and decision making, they need to be downscaled and allocated to the individual countries, so they can serve as benchmarks for national environmental performance and can be integrated with bottom-up sustainability criteria, e.g. national environmental standards. Transdisciplinary approaches are required, for co-designing and co-generating relevant knowledge by scientists and policy and decision makers. This also involves normative decisions about fair allocation of natural resources, emissions and burden sharing among nations and eventually institutions for the global governance of natural resources.