Nature-Based Solutions and Circularity in Cities

Abstract

Cities worldwide are facing a number of serious challenges including population growth, resource depletion, climate change, and degradation of ecosystems. To cope with these challenges, the transformation of our cities into sustainable systems using a holistic approach is required. The pathway to this urban transition is adopting the concept of circular economy for resource management. In this way, resources are kept and reused within the city. Nature-based solutions can be implemented for these tasks, and besides the circularity, they can provide additional benefits for the urbanites and the urban environment in general. This paper describes which urban challenges related to circularity can be addressed through nature-based solutions. This systematic review was developed within the COST Action CA17133 Circular City that investigates how nature-based solutions can be used to progress the circular economy in the urban built environment.

A Framework for Addressing Circularity Challenges in Cities with Nature-Based Solutions

“…Therefore, we propose a framework for addressing UCCs with NBS, which aims to guide practitioners and decision makers toward a better understanding of the role of NBS in the enhancement of resources management in cities and the mainstreaming of NBS in the urban setting. The framework includes the following: (1) a comprehensive set of UCCs based on gaps identified in existing frameworks as proposed by [14]; (2) a set of more than fifty NBS units and interventions (NBS_u/i) assessed in terms of their potential to address UCCs and classified according to the following categories proposed by [15]: nature-based solutions units (NBS_u) defined as "stand-alone green technologies or green urban spaces, which can be combined with other solutions (nature-based or not)" and NBS interventions (NBS_i) defined as "the act of intervening in existing ecosystems and in NBS_u, by applying techniques to support natural processes". This list also includes several Supporting units (S_u) that are required to create CE through NBS; and (3) a systematic approach for defining input and output (I/O) resource streams to and from NBS units/interventions that support creating CE through NBS.…”

Nature-Based Solutions in Cities—Contribution of the Portuguese National Association of Green Roofs to Urban Circularity

“…The implementation and promotion of NBS or nature-based green and blue infrastructure solutions and technologies enhancing the natural capital would be target opportunities for innovation in a really smart way as sustainable and cost-effective ways and interactive services for creating a greener, competitive and resource-efficient ("resourceful') urban circular economy (CE) [2,4,15,18,19]. The NBS and CE are side by side interconnected concepts towards the development of re-natured and circular cities.…”

“…Nature-based solutions implementation in the built environment contribute to a CE, for instance through the provision of ecosystem services (ES), and can be integrated at three scales: green building materials, systems for the greening of buildings and green urban sites [26]. Further on, NBS can support the cities shift from linear to circular resource management addressing the urban circularity challenges (UCC), as mentioned by Atanasova et al [15], through (1) 'restoring and maintaining the water cycle';…”

“…The following sections highlight specific and/or combined NBS initiatives and actions that support an urban circular thinking; and, provide an overview of the current existing EU policies and regulations aimed at a systematic development, consideration and implementation of NBS, which would be promoted by citizens, researchers, investors/funders, policy-makers Fig. 1 Porto's largest green roof located on Praça de Lisboa (Portugal) as an example of nature-based solution addressing a number of Sustainable Development Goals of the United Nations' 2030 Agenda, and enhancing specific urban circularity challenges (1, 5, 6 and 7) proposed by Atanasova et al [15] and practitioners, with a protagonist emphasis on the strategic character of the green infrastructure (GI) Associations in Europe. Further on, it will be highlighted as an example, the role of the Portuguese National Association of Green Roofs.…”

Causal Relations of Upscaled Urban Aquaponics and the Food-Water-Energy Nexus—A Berlin Case Study

“…The circular city (CC) is designed as a regenerative and restorative urban living system [28] by reducing, reusing, and recovering [29]. Nature is part of the transformation [30]: nature-based solutions (NBS) [31] can support closing the adaption gap [32] and the coupling of NBS units form a significant part of circularity in cities [33,34]. Urban agriculture, which is attracting increasing attention [35], contributes towards circular cities [36].…”