Implementing nature-based solutions for creating a resourceful circular city

Abstract

Resource depletion, climate change and degradation of ecosystems are challenges faced by cities worldwide and will increase if cities do not adapt. In order to tackle those challenges, it is necessary to transform our cities into sustainable systems using a holistic approach. One element in achieving this transition is the implementation of nature-based solutions (NBS). NBS can provide a range of ecosystem services beneficial for the urban biosphere such as regulation of micro-climates, flood prevention, water treatment, food provision and more. However, most NBS are implemented serving only one single purpose. Adopting the concept of circular economy by combining different types of services and returning resources to the city, would increase the benefits gained for urban areas. The COST Action Circular City aims to establish a network testing the hypothesis that: ‘A circular flow system that implements NBS for managing nutrients and resources within the urban biosphere will lead to a resilient, sustainable and healthy urban environment’. In this paper we introduce the COST Action Circular City by describing its main objectives and aims. The paper also serves as introduction to the review papers of the Action's five Working Groups in this Special Issue.

A review of nature-based solutions for urban water management in European circular cities: a critical assessment based on case studies and literature

“…This study aims to offer a brief review on NBS for UWM, together with a description of some relevant projects running within the action. In this COST Action, the definition of a common language and understanding across disciplines is seen as a crucial success factor, while circular economy (CE) concepts are seen as a key approach and NBS or green infrastructure (GI) solutions are seen as core elements of the toolbox (Langergraber et al 2019). Our working group has focused on the implementation of a safe and functional water cycle within the urban biosphere, where wastewater needs to be streamlined as a source of nutrients, hazardous pollutants that should be controlled (e.g., heavy metals or emerging organic contaminants), heavy metals being phytomined, the treated water looped back for irrigation, and recreational purposes should be considered side by side with sanitation, water supply or stormwater management.…”

Enhancing the circular economy with nature-based solutions in the built urban environment: green building materials, systems and sites

“…As defined by Langergraber et al (2019), nature-based solutions (NBS) are concepts that bring nature into citiesand in many cases this includes ideas for urban design that are inspired or derived from nature. Thus while NBS may be considered more generally as actions which protect, sustainably manage, and restore natural or modified ecosystems (IUCN 2019), the specific focus here is on the implementation of NBS within urban ecosystems.…”

“…Another important aspect when approaching contemporary urban systems is 'circularity'. Circular economy (CE) is an evolving 'umbrella' concept embodying internal complexities and multiple definitions, but is defined here (Langergraber et al 2019) as an economic system that aims at minimising waste and making the most of resources. In a circular system, resource input and waste, emission, and energy leakage are minimized by slowing, closing, and narrowing energy and material loops.…”

A review of nature-based solutions for resource recovery in cities

“…The present paper is a product of interdisciplinary cooperation among researchers from all 28 EU countries and 11 third countries within the EU-funded COST Action Circular City. Discussions among project members have produced a definition of nature-based solutions for the purpose of the COST Action, set out in Langergraber et al (2019). As such, the present paper defines NBS as technologies that bring nature into cities and those that are derived from nature, using organisms as principal agents if they enable resource recovery and the restoration of ecosystem services in urban areas.…”

“…The objective of this review is to provide a comprehensive overview of NBS applied and developed today to recover resources in cities, along current cutting-edge research and innovation, and to map out recoverable products as well as barriers, which represent the scope for further research. NBS can be applied to micro (household), meso (district) and macro (city and above) scales (Langergraber et al 2019).…”