Many of today’s most pressing environmental problems cross-cut jurisdictional, geographical, and administrative boundaries, creating interdependencies between different locations and between policy issues that no single actor can address alone. In practice, however, environmental policy is still often contained within the traditional responsibilities of the public sector and frequently judged ineffective, particularly in the European context. Whether and how interdependencies are actually associated with collaboration between policy actors has remained difficult to establish.  

This cumulative thesis focuses on interdependent environmental challenges that policy actors need to manage. Specifically, this thesis describes and analyses policy issue interdependencies and how they align with the collaborations of policy actors. In addition, this thesis explores how policy issue interdependencies can be revealed, concretised, and analysed. Interdependencies are effectively represented by networks, both as conceptual models and as analytical methods. Therefore, the studies in this thesis use a multilevel network model to explore the structural alignment between interdependencies and collaboration through the perspective of institutional fit.

This thesis reports findings from two research projects. The first project focuses on policy issue interdependencies relating to regional water degradation. This project describes and analyses these interdependencies in relation to collaborative networks across administrative boundaries (Papers I–III). The second project focuses on climate change impacts that propagate through food trade dependencies. This project contributes insights into the effect of climate change on food trade networks that cross national borders, illustrating a need for global climate adaptation (Paper IV).

Paper I introduces a methodological procedure for assessing policy issue interdependencies and develops policy issue networks by identifying overlapping causal relationships between policy issues and their environmental targets. By applying the procedure empirically to water governance, the paper shows that policy issue interdependencies vary in degree and type. Paper II combines the policy issue networks from Paper I with collaborative networks of policy actors in a multilevel network to analyse the impact policy issue interdependencies have on who policy actors select for collaborative partners and to clarify if and how patterns of collaboration among actors are formed. Paper III differentiates reinforcing and counteracting policy issue interdependencies and studies how these impact the perceptions and collaborations of the actors. Paper IV, shifting the focus to the global level, analyses climate change impacts related to food trade dependencies across national borders. Specifically, Paper IV investigates the impact of climate change on the structure of global food trade networks and therefore contributes a baseline scenario analysis for future studies that investigate policy issue interdependencies and policy actor collaborations on the global level.