Complexity and diversity of nexuses: A review of the nexus approach in the sustainability context.

Achieving global sustainability is a coupled human-environment system issue that requires resource planning and management that goes beyond siloed thinking. As such, there has been a growing interest in nexus thinking as a way to address global sustainability challenges in an integrated manner. In general, the nexus approach serves as a tool for systems integration, a platform for stakeholder engagement, and a method for exploring development pathways. This review traces the historical origin and progress of the nexus approach and examines the changes in the complexity and diversity of nexuses over time. Since its emergence in the early 1980s, the nexus approach has undergone several phases of development, resulting in more complex and diverse nexuses, whose components can be resource sectors/systems and/or specific social-ecological issues. This progress is favorable for the sustainable development agenda because the more components involved in a nexus, the greater the reality that can be potentially captured. Currently, however, there is still no consensus with regards to the key nexus components that could potentially cover all of the sustainable development goals. The development of frameworks for implementing the nexus approach and the identification of relevant indicators and target values to be used for assessing trade-offs and synergies are among the current issues with regards to the use of the nexus approach in the sustainability context.