The ability to effectively resolve complex environmental problems hinges upon the capacity to address several different challenges in concert. These challenges, what we refer to as policy issues, often relate to one another - they interdepend. Policy issue interdependency has been extensively theorised in the literature, yet few methodological approaches and little empirical evidence exist to translate the concept of policy issue interdependency to the on-the-ground realities facing policy actors in specific cases and contexts. We build from previous studies to develop a methodological procedure that investigates policy issue interdependencies in ways that take into account what measures and possible solutions policy actors have at their disposal in specific cases for specific environmental problems. By applying our methodological procedure to a case of water governance in Sweden, four insights emerged. First, validation by stakeholders confirms that our procedure produces reliable results. Second, we find that many, but certainly not all, policy issues are interdependent. More specifically, different patterns of policy issue interdependencies are associated with the biophysical and the governance spheres, respectively. Third, our results suggest that policy issue interdependencies are most important to consider when the overall level of interdependency is moderate. Last, our study raises new questions about policy actors' perception of policy issue interdependencies. In particular, a key question for future research would be if reinforcing (win-win) or counteracting (trade-off) interdependencies are easier to comprehend and act on for policy actors.

1. Environmental problems often span a set of challenges that each may engage different policy actors across different policy domains. These challenges, or policy issues, nonetheless exhibit interdependencies that may constrain the ability of actors to work together towards joint solutions.

2. Still, we have limited knowledge about whether and how policy issue interdependencies actually shape how actors collaborate.

3. Using data derived from two venues for collaborative water governance in the Norrstrom basin, Sweden, we investigate whether and how policy issues and policy issue interdependencies influence actors' selection of collaborative partners. We test two alternative sets of propositions; one set assumes that partner selection is driven by actors' engagement in policy issues and their interdependencies, while the other set emphasises social positions and actor attributes.

4. Our results show that in one venue, actors' choices of collaborative partner were associated with factors from both sets, but not with policy issue interdependencies specifically. In the other venue, only actor and relational attributes shaped social tie formation. These results suggest that how actors interact does not necessarily align with the policy issues and the policy issue interdependencies defined by the environmental problem they are to address.

5. Our results provide an important step towards arriving at evidence-based recommendations for more effective collaborative efforts in addressing complex environmental problems that no actor can address alone

Policy actors address complex environmental problems by engaging in multiple and often interdependent policy issues. Policy issue interdependencies imply that efforts by actors to address separate policy issues can either reinforce (‘win–win’) or counteract (‘trade-off’) each other. Thus, if interdependent issues are managed in isolation instead of being coordinated, the most effective and well-balanced solution to the underlying problem might never be realised. This study asks if reinforcing and counteracting interdependencies have different impacts on perception and collaboration. Our empirical study of collaborative water governance in the Norrström basin, Sweden, shows that policy actors often avoid collaborating when the policy issues exhibit reinforcing interdependencies. Our evidence indicates a perceived infeasibility of acting on reinforcing interdependencies. We also find that actors do not consider counteracting interdependencies (‘trade-offs’) at all when they engage in collaboration. Further, even though actors were aware of counteracting and reinforcing interdependencies, our analyses suggest they might be less aware of the former. These findings illustrate that actors either avoid each other due to policy issue interdependencies or, at best, ignore existing interdependencies when engaging in collaboration. Our study highlights the importance of problem perception in accomplishing integrated solutions to complex environmental problems, and of how understandings of different types of interdependencies shape collaboration in environmental governance. 

Climate impacts are predicted to become redistributed through countries’ reliance on food trade networks. This constitutes a significant challenge for climate adaptation planning, and may affect how countries engage in geopolitical and cooperative action. This paper explores potential impacts of climate change on global food trade networks. We ask: i) to what extent might climate change impacts entail a change in the structure of global food trade networks, and ii) how might a change in supply be distributed among the countries in trade blocs? We propose a simple network model to identify how climate change impacts on crops yields may be translated into changes in trade. Combining FAO and ISIMIP data, the model is applied to three key staple crops in the global food system: wheat, rice and maize. We use network community detection and functional cartography to analyse the degree to which global production is concentrated within different trade blocs before and after climate change impacts, and how countries distribute supply depending on their different network role. Our results predict that food trade networks may become more disaggregated as countries, particularly major global producers, may increasingly distribute their trade across modules with climate change impacts. Results also estimate that global food security may much depend on production change in a few major global producers, and whether trade blocs can balance production loss in some vulnerable countries. Overall, our model contributes a baseline scenario analysis of cross-border impacts on food trade networks, and insight into whether current food trade structures will allow counties to maintain current supply.