Cities are the main hubs of human activity and the engines of economic growth. In pursuit of such growth, cities are transgressing their local environmental boundaries. Ongoing urbanisation increasingly contributes to the human pressure on planetary boundaries and negatively affects planetary health. In a telecoupled world, cities externalise impacts by shifting production and many other functions away from their boundaries. At the same time, urban inhabitants and people who follow urban lifestyles but live outside cities are increasingly disconnected from nature. This Viewpoint highlights the role of degrowth in keeping an urban planet within planetary boundaries and suggests areas for further research and policy. Degrowth calls for meaningfully connecting planetary boundaries with cities and ensuring everyone receives a fair share of their ecological capacity. Degrowth calls for lower use of existing resources, highlights political power asymmetries, and moves beyond pricing interventions. Degrowth addresses three key aspects that connect cities and urban lifestyles to planetary boundaries: reducing production and consumption, connecting people and nature, and including nature (to a more substantial extent) in the design of cities and in what is used and consumed in cities. A radical degrowth transformation of cities is necessary to stay within a safe operating space for humanity.

Our planet is rapidly urbanizing. Research has recognized the complexity of city-driven dynamics, but our political realities have yet to catch up. A new narrative of sustainable urban development must become central to global policymaking to help humanity respond to the most pressing social and environmental challenges. 

Although biodiversity is a central component of food systems, conventional food systems have become one of the major drivers of biodiversity loss globally. There is an increasing need to transform food systems to provide sufficient and nutritious food, but with minimal negative impacts on the environment and society. One of the possible avenues to enable the sustainable transformation of food systems might be through the development of locally appropriate biodiversity-based solutions. In this paper we report the insights and lessons learned during the design and implementation of transdisciplinary projects that employed the concept of Sustainable Development Goals labs (SDG-Labs) to create biodiversity-based solutions to transform food systems. The six SDG-Labs outlined in this paper were implemented in Armenia, China, Japan, Madagascar, Thailand, and Uganda. Collectively they developed very diverse biodiversity-based solutions that used different components of biodiversity, ranging from novel cultivation systems with endangered plants, to gardens using tree species for wind breaks, or novel tea-forestry production systems. Beyond their ability to leverage different components of biodiversity to transform local food systems (also conserving biodiversity in the process), all solutions had multiple co-benefits such as climate change adaptation/mitigation and livelihoods generation, among other sustainability domains. Through a Strengths-Weaknesses-Opportunities-Threats (SWOT) analysis we synthesized the experiences gained during the design and implementation of all six SDG-Labs. The findings suggest the great promise of these transdisciplinary approaches for developing solutions at the biodiversity-food-climate nexus. However, this synthesis paper also points to the multiple context-specific challenges that should be overcomed to maximize the potential of SDG-Labs to both enable the sustainable transformation of (local) food systems and/or be scaled up effectively.

Recently two distinctly different conceptualisations of insurance value of biodiversity/ ecosystems have been developed. The ecosystem framing addresses the full resilience value without singling out subjective risk pref-erences. Conversely, the economic framing focuses exactly on this subjective value of risk aversion, implying that the insurance value is zero for risk neutral persons. Here we analyse the differences conceptually and empirically, and relate this to the broader socio-cultural dimensions of social-ecological resilience. The uncertainty of the Anthropocene blurs the distinction between subjective/objective. We show that the economic framing has been operationalised only in specific cases while the broader literature on resilience, disaster risk reduction, and nature-based solutions tend to address the full value of resilience. Yet, the empirical literature that relates to insurance value of biodiversity is hardly consistent with resilience theory because the slow underlying variables defining resilience are rarely addressed. We suggest how the empirical literature on insurance value can be better aligned with resilience theory. Since the ecosystem framing of insurance value captures the essence of the resilience, we propose using the concept resilience value as it may reduce the present ambiguity in terminology and conceptualisation of insurance value of biodiversity.

Financial advisers recommend a diverse portfolio to respond to market fluctuations across sectors. Similarly, nature has evolved a diverse portfolio of species to maintain ecosystem function amid environmental fluctuations. In urban planning, public health, transport and communications, food production, and other domains, however, this feature often seems ignored. As we enter an era of unprecedented turbulence at the planetary level, we argue that ample responses to this new reality — that is, response diversity — can no longer be taken for granted and must be actively designed and managed. We describe here what response diversity is, how it is expressed and how it can be enhanced and lost.

There is an emerging consensus that the health of the planet depends on the coexistence between rapidly growing cities and the natural world. One strategy for guiding cities towards sustainability is to facilitate a planning process based on positive visions for urban systems among actors and stakeholders. This paper presents the Urban Nature Futures Framework (UNFF), a framework for scenario building for cities that is based on three Nature Futures perspectives: Nature for Nature, Nature for Society, and Nature as Culture. Our framework engages stakeholders with envisioning the three Nature Futures perspectives through four components using participatory methods and quantitative models: identification of the socio-ecological feedbacks in cities, assessment of indirect impacts of cities on biodiversity, development of multi-scale indicators, and development of scenarios. Stakeholders in cities may use this framework to explore different options for integrating nature in its various manifestations within urban areas and to assess how different community preferences result in various cityscapes and distribution of associated benefits from nature among urban dwellers across multiple scales.

Biodiversity offsets and no net loss (NNL) are important tools for the international policy focus on ecological restoration. In this issue of One Earth, Kajula et al. call for national, public offset registers to enable evaluations of biodiversity offset programs. Here, we argue that we also need to control the main drivers of biodiversity loss.

Urban infrastructure will require transformative changes to adapt to changing disturbance patterns. We ask what new opportunities hybrid infrastructure—built environments coupled with landscape-scale biophysical structures and processes—offer for building different layers of resilience critical for dealing with increased variation in the frequency, magnitude and different phases of climate-related disturbances. With its more diverse components and different internal logics, hybrid infrastructure opens up alternative and additive ways of building resilience for and through critical infrastructure, by providing a wider range of functions and responses. Second, hybrid infrastructure points toward greater opportunities for ongoing (re)design at the landscape level, where structure and function can be constantly renegotiated and recombined.

Key insights on needs in urban regional governance - Global urbanization (the increasing concentration in urban settlements of the increasing world population), is a driver and accelerator of shifts in diversity, new cross-scale interactions, decoupling from ecological processes, increasing risk and exposure to shocks. Responding to the challenges of urbanization demands fresh commitments to a city–regional perspective in ways that are explictly embedded in the Anthopocene bio- techno- and noospheres, to extend existing understanding of the city–nature nexus and regional scale. Three key dimensions of cities that constrain or enable constructive, cross scale responses to disturbances and extreme events include 1) shifting diversity, 2) shifting connectivity and modularity, and 3) shifting complexity. These three dimensions are characteristic of current urban processes and offer potential intervention points for local to global action.