ABSTRACT
Environmental policies are typically designed and investment decisions are implemented to address specific, well-described issues be it to reduce, for example, traffic congestion or cut emissions of greenhouse gases into the atmosphere. This chapter concentrates on two related aspects that can have far-reaching implications for policy and investment making the ancillary cost and benefit impacts of any action, and the indeterminacy of causal relationships between system interventions and outcomes. The notion of ancillary or co-benefits and co-costs has long shaped, in different ways, the assessment of policy and investment outcomes, and is by no means new. Rather than generating co-benefits and minimizing co-costs of climate action, greenhouse gas emissions reductions and adaptation action may become the co-benefits of mainstreaming climate policy. A network demonstration is a convenient way both to represent the detailed coupling of climate actions and consequences, and to capture in systematic and aggregated form the emergent feature of actions and consequences.
