Metropolitan areas worldwide have grown rapidly and are usually surrounded by peri-urban zones that are neither urban nor rural. Despite widespread use of the term ‘peri-urban’, physical determination of these spaces is difficult due to their transient nature and multiple definitions. While many have identified peri-urban areas regionally or globally, questions persist on where exactly the peri-urban is located, and what are the most apt methods to delineate its boundaries. The answers are pertinent towards framing targeted policies for governing the dynamic socio-spatial transformations in these zones. This paper reviews peri-urban research over the last 50-plus years to discern the existing methodologies for its identification/demarcation and their applications. For this, a total of 3124 documents on peri-urban studies were identified through keyword searches in Scopus and Google Scholar databases. Thereafter, 56 documents were examined that explicitly dealt with demarcating peri-urban zones. Results reveal that there is no standout/generalized method for peri-urban demarcation. Rather, these approaches are geographically specific and vary across developed and developing countries, due to differences in land-use patterns, socioeconomic drivers, and political systems. Thus, we recommend developing a ‘pluralistic’ framework for determining peri-urban boundaries at the regional–global scale to enable better framing of relevant policies.

Carbon-neutral targets are a ‘new normative’ for cities and regions around the world. Such targets call for rapid system transformations, beyond the normal remit of urban-regional planning. In response, we propose a framework of theory and practice, in three parts: ‘trading zone’ concepts for collaborative planning; ‘scenario back-casting’ for longer horizons; and ‘synergistic thinking’ for systems transformation. We demonstrate this with the carbon-neutral journey of Greater Manchester. The results suggest the ‘new normative’ for cities and regions can be greatly facilitated by ‘synergistic scenario planning’, in theory and practice.

In this editorial we explore how the concept of the city region has evolved and what questions this raises for the role of urban futures, including visioning and foresight. The editorial and special issue highlight the importance of foresight techniques in city-region visioning, how power relations are shaped and transformed by these processes, and how important it is to link city-regional foresight with transitions theory and urban innovation, alongside the climate change and sustainability agendas. This paper also addresses the application of city-region visioning in the Global North/Global South, and what this means for future research.

The peri-urban, the areas ‘around, beyond and between’ the urban, may be the fastest expanding land-use around the world. Its many dimensions can include population density, economic activity, travel patterns, urban infrastructure, land cover, water basins or material flows. To explore the question ‘where is the peri-urban’, we adopt a twin-track approach. One is a conceptual ‘integrated framework’, which includes tangible parameters of land-use, relational linkages and systemic emergence. The second track is a practical ‘basic delineation’, a simple combination of population density and functional area, based on the Global Human Settlements Layer (GHSL), as developed by the project Peri-cene, through consultation with city-region partners. This delineation is here applied to a sample of 21 city-regions, covering in total 10% of the global urban population. The peri-urban land area in this sample is estimated at around 180,000 km², with a rapid growth rate of 2.9% per annum. This basic delineation is then combined with a wider set of social, economic and governance variables, to provide a basic global typology. The same method then highlights the internal peri-urban structure and growth pattern of each city-region, to derive a typology of six main peri-urban patterns. Overall, the basic delineation provides a foundation for quantitative analysis of the global peri-urban: and also supports further investigation of more complex systems-level problems and policy pathways.

Social Science is increasingly called on to address “grand challenges”, “wicked problems”, “societal dilemmas” and similar problematiques. Examples include climate change, the war on drugs and urban poverty. It is now widely agreed that the disciplinary structure of academic science, with its journals, curricula, peer communities, etc., is not well suited to such trans-disciplinary, ill-bounded, controversial issues, but the ways forward are not yet clear or accepted by the mainstream. The concept of a next generation paradigm of “Science 3.0” has emerged through work on sustainability systems analysis, and for this multiple channels for learning, thinking and communications are essential. Visual thinking in its many forms (from technical representation or mapping, to photography or video, to design or illustration, to fine art) can bring to the table tacit and “felt” knowledge, creative experience and links from analysis with synthesis. This paper first sketches the contours of a Social Science 3.0, and then demonstrates with examples how visual thinking can combine with rational argument, or extend beyond it to other forms of experience.