Juliana Gonçalves

Climate change is increasingly challenging existing urban systems. In many cities, the current capacity of urban water management systems to remove rainwater is insufficient to deal with extreme rainfall events that occur as a consequence of climate change. At the same time, climate change causes drought during increasingly long hot periods, resulting in declining groundwater tables which threaten building foundations. The Sponge Cities approach responds to this challenge by providing the capacity to store water when available (keeping the sponge dry enough) and release water when needed (keeping the sponge wet enough). In this project, we take an integrated approach to Sponge Cities that goes beyond water management to enable the realisation of sustainable urban spaces that restore and preserve the health and well-being of humans and ecosystems in the face of amplifying socio-ecological challenges.

This project is a flagship of the Climate Action Program of TU Delft under Theme III – Climate Change Adaptation.

OUR POSITION: Sponge Cities as an integrated urban planning and design concept

Juliana E. Gonçalves, Maryam Naghibi, Marcin Dabrowski, Claudiu Forgaci

The idea of Sponge Cities has influenced the planning of many Chinese cities and is becoming increasingly popular in climate adaptation narratives across the world. In the academic literature, the term Sponge Cities was first mentioned in 2005. Since then and particularly after 2015, the body of literature on Sponge Cities has been growing, spanning across disciplinary and sectoral boundaries, including water management, climate adaptation, and landscape architecture. However, many studies related to Sponge Cities lack a conceptual description of what a Sponge City is or should be. Other studies confound the concept with related terms like low-impact development (LID), water-sensitive urban design (WSUD) or nature-based solutions (NbS). While LID, WSUD and NbS may be strategies to implement Sponge Cities, a planning concept needs to consider all the elements in an urban system, including governance networks, material and energy flows, urban infrastructure and form, and socio-economical and socio-ecological dynamics. In parallel, related literature on e.g. water management and climate adaptation shows an increase in integrated approaches and definitions in which not only water but also social and ecological processes need to be met with extra spatial capacity in the urban environment.

Therefore, despite the increasing interest, a clear definition that outlines the scope of Sponge Cities is still missing. The lack of conceptual clarity is problematic because it hinders effective implementation of the concept in planning practice and prevents a consistent assessment of Sponge City interventions in urban contexts. Out first step in this project is to conceptualise Sponge Cities as a planning concept by reviewing the academic literature related to Sponge Cities to (1) identify the most influential studies, (2) trace the origins and development of Sponge Cities as a planning and design concept, (3) compare how the concept is defined across fields of application (e.g., water management and climate adaptation), and (4) develop a definition of Sponge Cities from an integrated planning and urban design perspective, addressing conceptual and operational tensions across policy and disciplinary fields. An integrated definition is expected to provide a clear foundation for developing guidelines and practical recommendations for the planning and design of Sponge Cities.

OUR POSITION: A Transformative Approach to Urban Climate Adaptation

Juliana E. Gonçalves

(work in progress)

As extreme weather events become more frequent and intense, urban areas are confronted with increasing climate risks, which are diverse in nature, magnitude, and scale, thus creating local adaptation challenges unique to each urban setting. The current top-down, incremental, short-term, and fragmented approach to climate adaptation is insufficient to address challenges of such complexity. In response, Transformative Urban Adaptation (TUA) promotes an integrated, systemic, participatory, situated, and transdisciplinary approach grounded in climate justice to address the impacts of climate change by fundamentally altering societal structures, behaviours and attitudes, and (spatial) systems to adapt to a changing climate. Unlike traditional adaptation measures, which often focus on incremental changes to existing systems, transformative adaptation involves more radical shifts in vision, thinking, and action, while addressing the need to build socio-ecological resilience in the face of climate change and other spiralling socio-ecological crises. We can explain the TUA approach through the concepts of (work in progress):

• Climate Justice: A transformative approach to urban climate adaptation must take climate justice claims seriously. TUA prioritises addressing underlying socio-spatial inequalities, ensuring that adaptation efforts benefit especially those most marginalised by the system and currently socio-cultural structures and at climate risk. Through the lens of climate justice, TUA centres on how power dynamics shape adaptation processes, actions and outcomes, critically challenging the status quo and recognising that business as usual is no longer sufficient to address the magnitude current socio-ecological crises.
• Systemic Change: TUA requires transforming not just individual practices and behaviours or single sectors but entire systems and institutions. This entails rethinking economic models, organisational structures, and societal norms to build resilience to climate change.

• Integrated (Spatial) Planning: TUA seeks to connect short-term impacts/risks to long-term implications of climate change and aims to build adaptive capacity across sectors and spatial scales, from people to planet, to withstand present, transitional, and future uncertainties and shocks. This requires multidimensional data and decision-support tools that capture socio-spatial-temporal dynamics.

• Participatory Structures: TUA requires innovative organisational structures and decision-making processes that involve diverse groups, including individual citizens, communities, academia, businesses, and civil society organisations. This ensures that adaptation strategies are context-specific and responsive to local needs.
• Situated Knowledge: TUA integrates situated knowledge by emphasising the value of local experiences, traditional practices, and community-based understandings of climate change. It challenges the dominance of technocratic or homogenised approaches by highlighting that what counts as ‘knowledge’ is contested and deeply political. This approach not only increases the effectiveness of adaptation but also fosters agency and ownership among those most directly affected by climate change.
• Transdisciplinary Approach: TUA requires openness to work across disciplines and sectors, and beyond academia or public institutions. Working in a transdisciplinary way is a transformative journey in itself that requires not only new tools, processes, and structures but also a deep reflexive process on the role of experts in shaping climate discourse and action.