When Are Parties Good for the Environment?

• In Event: Political Economy of Climate Change

Abstract

Green parties have garnered increasing attention as a potential alternative to mainstream political parties in the face of catastrophic climate change. Though the evidence is mixed (Hilbig and Riaz 2023; Hoffmann et al 2022; Pike 2022), recent work indicates that experience with climate extremes can shift voters away from mainstream parties and toward Green parties. This literature is grounded in the premise that by understanding the drivers of Green support, we can identify key mechanisms underlying transformations toward a greener economy. But with no existing evidence on their policy influence, whether Green parties do affect environmental outcomes remains a puzzle. To address this question, we develop one of the first game theoretic models of electoral competition where the environment is added as a second dimension in the political arena. Our model illuminates two key pathways by which Greens affect policy. First, Green parties shape environmental policy via their position in government (votes) and coalition opportunities. Though Green vote shares have been low over time globally, Greens influence policy in a second way, through their impact on mainstream party behavior; what we call the shadow effect of Green parties. As with any political issue, mainstream parties compete with one another, as well as with an existing Green party, over the political response to new environmental demands. Electoral competition leads Green parties to invoke a shadow effect on environmental policy, as their potential to steal mainstream party votes can either stifle or stimulate the significance of the environment within mainstream party agendas. For example, when Greens are considered “issue owners” on the environment, if Green vote share rises this may actually lead mainstream parties to de-emphasize the environment so they can focus on gathering votes from issues on which they are perceived as more component; a pressure that is not present in a system without a single-issue “environmental” party. These dynamics can in turn lead to less (or more) environmental policy on the agenda of the eventual government. We empirically investigate these dynamics using a unique party-year dataset of public environmental attitudes, national electoral outcomes in Europe, and respective mainstream party positions from 1960-2022. Our analysis demonstrates the extent to which green party support, mainstream party response, and their interaction translate into actual environmental and climate legislation. Using the Climate Laws of the World Dataset, we assess how both the indirect electoral channel and direct effect of Green party support have shaped policy outcomes over time. Making use of data from the Comparative Manifesto Project, we first show that as green vote share increases, mainstream parties deemphasize the environment in their political agendas. But as the salience of the environment rises, we find the opposite, suggesting that if momentum can be sustained, Green parties can even affect policy indirectly.

Authors

• Aleksandra Conevska, Harvard University

• Can Mutlu, Harvard University