Abstract for: A conceptual systems model of an Anthropogenic delta

Nature-based Solutions (NbS) are increasingly promoted as strategies for sustainable adaptation in Anthropogenic deltas. However, realization of the potential of NbS remains elusive, largely because the systemic effects – outcomes spanning the social, economic, and ecological domains - are poorly understood and are rarely assessed together. In response, this paper explores how the dynamics of complex deltaic systems shape the varying effects of NbS interventions through conceptual systems modelling. An overarching systems approach and an ecosystem services lens. The main activities are conceptual systems modelling; a literature search; and; empirical orientation and consultation with experts. We conceptualize an aggregated causal loop diagram (CLD) of a generic Anthropogenic delta, designed to explore the system feedback associated with different NbS for climate change adaptation in deltas. We apply the CLD to the Ebro Delta in Spain. The CLD depicts the interlinkage of the human system and the deltaic ecosystem, highlighting how this relationship undermines resilience to climate change. The ecosystem services concept helps to shed light on the mechanics of NbS interventions, illustrating how they affect deltaic feedback loops. NbS such as ecological flows, sediment by-passes, or wetland restoration can dampen — or ideally reverse — feedback loops that drive the loss of deltaic resilience. Beyond its immediate application in understanding systemic effects (and therefore potential trade-offs) of deltaic NbS in a qualitative and integrative manner, the model also lays the groundwork for future development of a quantitative system modelling approach for a specific delta. refine and rephrase language (use of grammar, spelling, syntax, etc)