Access to urban green spaces in Hannover: An exploration considering age groups, recreational nature qualities and potential demand.

City dwellers' accessibility of urban green spaces (UGS) has recently gained immense interest in research and policy. Related scientific studies thus far have focused primarily on spatial distances, largely missing considerations of UGS qualities. We analysed the entire UGS setting of Hannover considering the recreational nature quality and potential demands to identify age-appropriate green spaces by applying a geographic information system analysis of several data sets. Additionally, we assessed the accessibility of UGS for different age groups, varying recreational nature qualities, and potential demands. Results indicate that children and elderly people have poor access to UGS that offers age-related requirements to enable unrestricted nature-based recreation. Nature quality and age-related requirements play a significant role in the assessment of UGS for recreation and accessibility. We conclude that detected vulnerabilities regarding age-related recreation in cities are anchors to mainstream the issue and enhance future planning practices and research.

How the COVID-19 pandemic impacts social scientific research on sustainability: questions of methodology, ethics and justice: comment on Santana et al. 2021.

In a highly relevant contribution, Santana et al. (2021) outlined the challenges for qualitative enquiries during the pandemic. We agree that overcoming these challenges is very important since qualitative research is vital for understanding both the impacts of COVID-19 on human communities around the globe and its significance for sustainable futures. However, we argue that a more fundamental approach is needed to address problems within scientific organisations, thinking and practices that directly affect qualitative research capabilities. In this comment, we focus on justice, research organisation, the ways social scientists position themselves and changed understandings of social worlds.

Making the COVID-19 crisis a real opportunity for environmental sustainability.

An optimistic narrative has gained momentum during the first year of the pandemic: the COVID-19 crisis may have opened a window of opportunity to "rebuild better", to spur societal transitions towards environmental sustainability. In this comment, we review first evidence of individual and political changes made so far. Findings suggest that economies worldwide are not yet building back better. Against this background, we argue that a naïve opportunity narrative may even impair the progress of transitions towards environmental sustainability because it may render green recovery measures ineffective, costly, or infeasible. Based on these observations, we derive conditions for green recovery policies to succeed. They should consist of a policy mix combining well-targeted green subsidies with initiatives to price emissions and scrap environmentally harmful subsidies. Moreover, green recovery policies must be embedded into a narrative that avoids trading off environmental sustainability with other domains of sustainability-and rather highlights respective synergies that can be realized when recovering from the COVID-19 crisis.

Covid-19 as a Social Crisis and Justice Challenge for Cities.

The article deals with Covid-19 as a social crisis and justice challenge for cities. It describes how Covid-19 shines a spotlight on the uneven distribution of goods and burdens, opportunities and resources that we find in most of the world's cities today; inequality and justice challenges arise from both the crisis itself and some of the policy reactions to it, such as the stay-at-home orders and economic lockdowns. It shows how exposure and vulnerability to Covid-19 emerges mainly at the intersection between different dimensions of disadvantage and marginalization. The example of housing and green space provision is used to discuss this general argument in more detail. The article concludes that to overcome the social crisis and justice challenge posed by Covid-19, we have to tackle the underlying structures/mechanisms leading to inequitable outcomes in today's cities, and to re-think the social and justice yardsticks of current urban sustainability and resilience debates and strategies.

Compact or spread? A quantitative spatial model of urban areas in Europe since 1990.

Changes in urban residential density represent an important issue in terms of land consumption, the conservation of ecosystems, air quality and related human health problems, as well as the consequential challenges for urban and regional planning. It is the decline of residential densities, in particular, that has often been used as the very definition of sprawl, describing a phenomenon that has been extensively studied in the United States and in Western Europe. Whilst these studies provide valuable insights into urbanization processes, only a handful of them have reflected the uneven dynamics of simultaneous urban growth and shrinkage, using residential density changes as a key indicator to uncover the underlying dynamics. This paper introduces a contrasting analysis of recent developments in both de- and re-concentration, defined as decreasing or increasing residential densities, respectively. Using a large sample of European cities, it detects differences in density changes between successional population growth/decline. The paper shows that dedensification, found in some large cities globally, is not a universal phenomenon in growing urban areas; neither the increasing disproportion between a declining demand for and an increasing supply of residential areas nor actual concentration processes in cities were found. Thus, the paper provides a new, very detailed perspective on (de)densification in both shrinking and growing cities and how they specifically contribute to current land take in Europe.

Endless urban growth? On the mismatch of population, household and urban land area growth and its effects on the urban debate.

In European cities, the rate of population growth has declined significantly, while the number of households has increased. This increase in the number of households is associated with an increase in space for housing. To date, the effects of both a declining population and decreasing household numbers remain unclear. In this paper, we analyse the relationship between population and household number development in 188 European cities from 1990-2000 and 2000-2006 to the growth of urban land area and per capita living space. Our results support a trend toward decreasing population with simultaneously increasing household number. However, we also found cites facing both a declining population and a decreasing household number. Nevertheless, the urban land area of these "double-declining" cities has continued to spread because the increasing per capita living space counteracts a reduction in land consumption. We conclude that neither a decline in population nor in household number "automatically" solve the global problem of land consumption.

Population decline in Polish and Czech cities during post-socialism? Looking behind the official statistics.

The evolving debate on "urban shrinkage" mirrors an increasing interest in demographic phenomena on the part of urban scholars. This paper discusses ambiguous evidence about recent population decline in the large cities of Poland and the Czech Republic, with a particular focus on Lódz and Brno in general and their inner cities more specifically. By applying a mixed-method approach, the paper identifies indications of inner-city repopulation and socio-demographic diversification which are not yet apparent in register or census data. It is argued that there are indications of a silent transformation of traditional residential patterns and neighbourhoods in east central Europe. In the inner cities, this is reflected, amongst other things, by the presence of new households that may be called "transitory urbanites".