Adapting risk assessments for a complex future

Human activities have progressively eroded the biosphere basis for our societies and introduced various risks. To navigate these risks, or potential undesirable outcomes of the future, we need tools and an understanding of how to assess risk in a complex world. Risk assessments are a powerful tool to address sustainability challenges. However, two issues currently hamper their ability to deal with sustainability risks: the limited sustainability science engagement with the multifaceted nature of risk and the lack of integration of social-ecological, complex, and resilience thinking into risk assessment. In this Perspective, we review and synthesize the wide range of risk definitions and uses and juxtapose them with knowledge on complex adaptive social-ecological systems. Through this synthesis, we highlight the strengths of each risk approach and outline five challenges that, if overcome, could turn risk assessments into a much-needed multifaceted toolbox for dealing with the certain uncertainty of a complex future.