Greening cities, namely installing new parks, rooftop gardens or planting trees along the streets, undoubtedly contributes to an increase in wellbeing and enhances the attractiveness of open spaces in cities. At the same time, we observe an increasing use of greening strategies as ingredients of urban renewal, upgrading and urban revitalization as primarily market-driven endeavours targeting middle class and higher income groups sometimes at the expense of less privileged residents. This paper reflects on the current debate of the social effects of greening using selected examples.

Water is of particular importance for cities. Many fast growing megacities are facing serious water-related problems including pollution, eutrophication, missing wastewater treatment and, perhaps most importantly, a severe scarcity of clean water. In the entire urban world, water resources are used in an inefficient way. But there is great potential: this opinion paper discusses ecosystem services provided by waters-hereafter referred to as blue urban ecosystem services-and respective links to green infrastructure and the services they provide for human wellbeing.

A nature-based approach to climate resilience aims to challenge and re-frame conventional environmental management methods by refocusing solutions from technological strategies to socio-ecological principles such as human well-being and community-based governance models, thereby improving and legitimizing the delivery of ecosystem services (ES).

Acknowledgement by the International Union for the Conservation of Nature (IUCN) that geodiversity is part of natural diversity and geoheritage is part of natural heritage should help to strengthen the position and delivery of geoconservation through engagement with the wider nature conservation agenda.

The development of green space along urban rivers could mitigate urban heat island effects, enhance the physical and mental well-being of city dwellers, and improve flood resilience. A linear park has been recently created along the ephemeral Pedieos River in the urban area of Nicosia, Cyprus. Questionnaire surveys and micrometeorological measurements were conducted to explore people's perceptions and satisfaction regarding the services of the urban park. People's main reasons to visit the park were physical activity and exercise (67%), nature (13%), and cooling (4%).

The aim of this study was to assess the environmental impact of three alternatives for wastewater treatment in small communities. To this end, a Life Cycle Assessment (LCA) was carried out comparing a conventional wastewater treatment plant (i.e. activated sludge system) with two nature-based technologies (i.e. hybrid constructed wetland and high rate algal pond systems). Moreover, an economic evaluation was also addressed. All systems served a population equivalent of 1500 p.e. The functional unit was 1 m3 of water.

The global climate change agenda proceeds at an incremental pace while the Earth is approaching critical tipping points in its development trajectory. Climate action at this pinnacle juncture needs to be greatly accelerated and rooted in the fundamentals of the problem-human beings' disconnection from nature. This paper underscores the valuable role nature and nature-based solutions can play in addressing climate change at the city scale and its implications for broader sustainability.

Soil sealing is one of the most pervasive forms of soil degradation that follows urbanization and, despite innovative pavements (i.e. pervious) are being installed in urban areas to mitigate it, there is little research on the effects of pervious pavements on soil water and carbon cycle and on the physiology of urban trees. The aim of this 4-year experiment was to assess the effects of three pavements, differing in permeability to water and gases, on some soil physical parameters, and on growth and physiology of newly planted Celtis australis and Fraxinus ornus.

Using Barcelona and Shanghai as case studies, we examined the nature-based solutions (NBS) in urban settings—specifically within cities experiencing post-industrialization and globalization. Our specific research questions are: (1) What are the spatiotemporal changes in urban built-up land and green space in Barcelona and Shanghai? (2) What are the relationships between economic development, exemplified by post-industrialization, globalization, and urban green space?

Contemporary societies are facing a broad range of challenges, from pressures on human health and well-being to natural capital depletion, and the security of food, water and energy. These challenges are deeply intertwined with global processes, such as climate change and with local events such as natural disasters. The EU's research & innovation (R&I) policy is now seeking to address these challenges from a new perspective, with Nature-Based Solutions, and turn them into innovation opportunities that optimise the synergies between nature, society and the economy.