Urban regions both cause and concentrate most of the environmental challenges currently facing our society. They contribute substantially to the global emission of greenhouse gases and are one of the main causes of dramatic biodiversity loss at regional and planetary scales. At the same time, increasing vulnerability to meteorological hazards, such as flooding, and longlasting heatwaves, as well as increasing temperatures due to the pronounced urban heat island effect challenge the environmental quality and livability of cities. The ecological functions and structures of Urban Green Spaces (UGS), however, can help ameliorate some of these challenges by cooling down the city, sequestering and storing carbon, and providing habitat for urban wildlife. To harness the full ecological potential of UGS, a critical examination and reorientation of their planning, design, and management strategies is imperative. Over the past decades, urban design and form have emphasized confining, domesticating, and meticulously shaping nature within UGS, thereby assigning significant public value to highly unsustainable and environmentally costly UGS. This can present challenges in terms of low social acceptance and potential public resistance for efforts to transition values associated with UGS landscape architecture towards more ecologically-driven paradigms.

In this thesis I explore more just and socially acceptable pathways through which these ecologically motivated UGS transformations can be realized. Adopting both quantitative and qualitative methods, I look specifically at how individuals can manifest their agreement or disagreement with UGS transformations through their various roles in society—as privatesphere decision-makers as well as citizens. Drawing heavily on environmental psychology and human geography research, I understand social acceptance for ecologically motivated UGS transformations both as pro-environmental behaviors in the private sphere (i.e., domestic gardening) and attitudes toward specific hypothetical UGS initiatives.

First, I demonstrate how gardening behaviors in private domestic gardens are relational practices dependent on the biophysical reality of the gardens in question, but also intimately associated with both gardeners´ internal and external behavioral determinants. Based on empirical evidence, I next propose and raise arguments for the necessity of integrating indicators of environmental justice into social acceptability assessments to elicit potential maldistribution of the goods and bads associated with transformations in public UGS. Furthermore, to guide the design of informational strategies for enhancing social acceptance, I unpack the importance and potential effectiveness of environmental knowledge in fostering the social acceptance of UGS transformations. Lastly, by means of public participatory geographic information system tools, I demonstrate the benefits of adopting place-based approaches to investigate local social acceptance and argue the need to de-universalize acceptance by spatially contextualizing this phenomenon.

In sum, this thesis argues the importance of interdisciplinary research, bridging environmental and social psychology, human geography, ecology, and other natural sciences to address complex sustainability challenges. Moreover, I advocate for integrating attitudes, preferences, and behaviors under the same umbrella term of social acceptance to better recognize the distinct roles of citizens as agents of urban sustainability transformations. This theoretical move thus calls for more effective collaboration across research disciplines and administrative silos of practitioners, working towards the shared goal of realizing a better Anthropocene for generations to come.