European cities’ barriers to carbon neutrality: identifying vicious circles hampering effective implementation

The transition to carbon neutrality in European cities is a cornerstone of the European Commission’s new Green Deal, with the ambitious target of delivering 100 “Climate-neutral and smart cities” by 2030. Although cities are increasingly recognised as pivotal actors in environmental governance, a persistent gap, largely acknowledged in the literature, remains between policy ambitions and implementation outcomes. This paper presents a comprehensive analysis of the structural, financial, organizational, political, and technical barriers that hinder the effective implementation of carbon-neutral strategies at the city level. Drawing on case study analysis from 10 diverse European cities, the study applies a qualitative methodology integrating insights from 30 collaborative workshops held between 2023 and 2024 and 12 follow-up interviews with city practitioners. The first round of findings confirms many of the key barriers identified in the literature. More critically, insights from this study reveals that these barriers and their underlying drivers operate through complex interdependent networks of causes and effects - what we conceptualise as “vicious circles of barriers.” Identifying these vicious circles provides a deeper understanding of the self-reinforcing carbon lock-in dynamics that constrain urban transformation and highlights that many underlying drivers extend beyond the institutional capacities of the cities themselves. Therefore, this paper calls for a renewed examination of the role of cities within broader climate governance.