Systematic review and comparison of densification effects and planning motivations

Abstract

Do higher urban densities contribute to more sustainable cities and communities? This paper examines the effectiveness of higher density (as a means) for achieving sustainable urban development (the goal) following three lines of enquiry. First, a systematic review of the scientific literature (n = 229 peer-reviewed empirical studies) is presented on the effects of urban density. Second, the motivations for increasing urban density are studied in a systematic review of Swedish planning practices based on the comprehensive urban plans in 59 municipalities. Third, these two studies are compared to find matches and mismatches between evidence and practice. Although positive effects exist for public infrastructure, transport and economics, there are also considerable negative environmental, social and health impacts. This creates a challenging task for urban planners to assess the trade-offs involving densification and accommodate current urbanisation rates. Some topics are found to be over-represented in research (transport effects), seldom discussed in practice (environmental impact), and misaligned when comparing motives and evidence (social impact). Furthermore, for some topics, urban density thresholds are found that are important because they may explain some of the divergences in the results between studies. PRACTICE RELEVANCEThe transfer of knowledge from research to planning practice is a serious concern as planning strategies are not aligned with scientific evidence. Planning practice in Sweden is more positive about the contribution of higher density to sustainable urban development than the results of empirical studies warrant. The largest deviation is found in relation to the social impacts of higher density where the planning arguments are not aligned with the evidence. Several reported negative effects of densification (e.g. water management, recreational infrastructure, biodiversity) are not sufficiently accounted for in Sweden's

Growing Inwards: Densification and Ecosystem Services in Comprehensive Plans from Three Municipalities in Southern Sweden

“…Swedish municipalities are legally obliged to clarify how they plan to use land and water resources; how the built environment should be used, developed and conserved; and how the municipality will secure national interests and comply with environmental quality regulations [9]. The comprehensive plan is the document in which planners attempt to negotiate conflicting goals [2,10,11]. In comprehensive plans, ecosystem services are often outlined as prerequisites for successful densification.…”

“…The concept of holism is relevant, as it points to the fact that urban planning is not merely about a political will to merge all good values but a conscious understanding of how changing one factor in a city may affect another. Berghauser Pont et al [10] analysed 59 Swedish comprehensive plans and demonstrated that while densification has positive effects on public infrastructure, transport and economy, there were negative environmental, social and health impacts. Naess et al [5], in a more theoretical article, critically discussed how urban densification is conceptually aligned with ecological modernisation, where de-coupling economic growth from environmental limitations makes it theoretically possible to combine densification with a lush environment.…”

Who Are We Building for? Tracing Universal Design in Urban Development

“…According to this research, positive effects exist for public infrastructure, transport, and economics, while there are considerable negative environmental, social and health impacts. Related to health issues, particularly negative effects on mental health are associated with densification, where the compactness of the built fabric and the lack of open space plays an important role when explaining perceived urban stress [13]. Furthermore, sustainability within planning and building is still strongly associated with the green dimension, further reinforced by concerns about climate change, while social aspects are less discussed.…”

Comparing types and patterns: A context-oriented approach to densification in Switzerland and the Netherlands

“…While governments worldwide rely on densification policies to reduce land consumption from urban growth, possible ecological, economic and social effects of urban densification are being widely discussed (Berghauser Pont et al, 2021). Many of these effects are not inherent to densification – they manifest in some cases but not in others.…”