or rural exodus, as two of the decisive push and pull factors for urban growth, or the rebuilding of cities after destructions of war, to accommodate pressing needs for affordable housing or to revive economies and secure employment. Global shifts in industrial production affected not only the social fabric of entire cities but also released vast central areas for urban revitalization, offering opportunities to rethink needs and opportunities for urban habitation as such. Urban habitats have also always been a field of debates and have been impacted by them, like by the questioning of modernist design paradigms, the iterations on new building types, the criticism of urban sprawls, the demands emerging with the ‘second demographic shifts’ (Lesthaeghe 2010) or activist campaigns regarding who is owning the city, to mention a few.
The question of ownership and who has control and agencies on urban habitation has always been crucial. While mass social housing has been justifiably criticized for its normative, social engineering paradigms, it was able to engender affordable housing for vast sections of urban populations. The ongoing shifts away from it towards profit‐driven housing developers and the commodification of housing again influence the societal balances in cities in their totality, causing inequalities and segregations that impact the very opportunities to equally participate, contribute, and benefit from the resources that cities offer.
An often referred to point of reference for discussions on urban habitation is the UN's prediction that by 2050 68% of the world population is going to live in urban areas, from currently 50% on average (UN Department of Economic and Social Affairs Population Division 2019). While the respective migrations will most impactfully affect the developing regions in Asia and Africa, urban populations as well increase in European and North American cities, if so modestly. Here, the respective push and pull factors like the shifts in global industrial production influence cities differently, can either lead to significant depopulation in cities like Detroit or to the release of vast central areas for urban revitalization projects in Northern Europe. New developments here face, to a certain extent, comparable challenges as those in megacities like in Asia – similarly requesting socio‐spatial strategies to engender inclusivity and a sense of belonging. Also, with the impacts of social diversification and segregation and the global migration, it is – beyond the crucial provision of liveable, affordable shelter – in any context crucial to cater to the integrative potentials shared habitats can have.
Closely related to the complex push and pull factors that ignite migrations, globally and locally, towards and within cities, are the growing impacts of inequality. Saskia Sassen (2014) argues that unregulated global finance sectors tend to threaten liveability at localities across the world, with their enormous financial assets, their global reach, and sophisticated legal, financial and engineering skills. These resources cause systemic ‘expulsions’ in both developed and developing places around the globe, from social security, safe employment, affordable housing, and healthy environments. Raquel Rolnik (2019) argues likewise, that neoliberalism, withdrawing welfare policies and the simultaneous expansion of asset markets led to the commodification of housing at a global scale, while still being a fundamental necessity of human subsistence. A ‘wall of money’ (Rolnik 2019) emerged seeking global opportunities for profitable investment, to become a ‘peculiar form of value storage in housing that directly relates macroeconomics to the homes of individuals and families’. As a consequence, relative housing cost burdens have grown significantly, also in a majority of OECD countries (OECD 2019a), affecting in particular low‐income households but increasingly also middle‐class families. These tendencies, if not controlled and balanced appropriately, lead ever more to significant lack of affordable housing, and displacements.
Also, significant demographic shifts impact habitation in cities. Families have changed and diversified substantially over the past 30 years (OECD 2011), and in particular the mismatch between decreasing numbers of families with children and increasing incidents of single‐person households, childless couples and seniors preferring to age‐in‐place and the care‐gaps emerging with it are of concern when considering the social sustainability of habitats. The societal diversification and segregation, local and global migration also make what ‘community’ and being part of a neighbourhood means for dwellers increasingly diverse, dynamic, and contested, noting that particularly vulnerable groups in populations depend more on formal or informal support networks. At the same time, new forms and engagements of coexistence, sharing and caring emerge together with claims for more agency and participation as trends that habitats should be able to respond to.
Built environments, and with them their habitats, contribute significantly to global warming. In Europe, the building sector is responsible for half of all extracted materials (European Commission 2011). Globally, almost 40% of carbon emissions can be accounted to the building and construction sector (UNEP 2015). But urban habitats are at the same time also affected by climate change – by both internal factors such as urban heat islands but increasingly also by external factors. The climate crisis, in particular in the southern hemisphere, leads to significant migrations out of rural areas into cities, predominantly within their home regions but ever more also to the cities in Europe and North America.
The Sustainable Development Goals (SDG) set by the United Nations in 2015 can be taken as quintessential benchmarks that respond to these multilayered, correlating challenges and that manage to condensate them into criteria also for those that contribute with their works to sustainable future urban habitation. In particular the Sustainable Development Goal 11 for ‘Sustainable Cities and Communities’ requests to make habitats inclusive, safe, resilient, and sustainable. It covers aspects also the authors in this book contribute to from different domains – the provision of safe, inclusive and affordable housing, green and public spaces, and infrastructure, facilities and services as common resources. It claims for empowerment, inclusion and participation in integrated urban policies and development. Environmental protection and resilience to cope with climate change are to be secured, also by providing capabilities for sustainable and resilient buildings.
While these are global guidelines, they illustrate the complexity of what is at stake, comprising social, economic, and environmental criteria that have to be understood, balanced and responded to in specific contexts and projects. There is a lot of knowledge in the various domains that work on these questions, in design, planning, policies, critical urbanism, economy, urban geography, anthropology or sociology, to mention a few, showing also how essential the contributions from different, often collaborating domains are. As ways to derive answers, Nigel Cross (1982) distinguished between problem – and solution‐focused approaches, to compare how designers working on future potentials and researchers working on past and present actualities face the issues at stake, maybe as the common territory both contribute to with their findings. Cross claims that designers work is as much research‐driven as that of other experts, but while these concentrate on problems, designers act in a solution‐focused way – learning about the nature of problems posed by a particular socio‐spatial context by studying and trying out potential solutions until an appropriate one is found. Framing the conditions and references for such responses has changed consistently, increasingly bridging and blurring the lines between design and research and also shifting from domain‐specific expertise to context‐ and issue‐specific approaches. Herbert Simon's statement that designs are ‘courses of actions’ to improve ‘existing situations into preferred ones’ (1969) can be used to point at the changing paradigms, with the aesthetic or functional concerns for a physical context or device merging evermore with the attention given to the qualities of its performances and experiences.
With the expanding complexities and uncertainties of the issues at stake and the growing awareness for needs to take action, more significance is given to the impacts integrated or collaborative research practices can have, how these have evolved and often blur the boundary to design. More awareness is given to the forms of knowledge decision‐makers follow, criticizing evermore the normative paradigms referred to in urban planning and housing policies. The involvements of other expertise like urban sociologists, anthropologists or social‐ and health service experts cater to more informed and inclusive planning policies and design strategies. More responsive approaches are also engendered by the expanded opportunities and capabilities
