Abstract
The environmental crisis of the XXI century is increasingly manifesting its grimmest side, especially in cities where urbanisation trends are exacerbating several challenges. Air pollution, urban heat island effects, flooding are only some of the most evident consequences on public health and quality of life caused by climate change and the lack of adequate green and public spaces. Climate change mitigation and adaptation, as well as resilience, are nowadays keywords on agendas of public institutions around the world. Thus, Nature-based Solutions (NBS) emerged in the last years as a promising approach to enhance sustainable urbanisation, ecosystem restoration and improve risk management and climate change resilience. While NBS are usually designed to tackle specific challenges, they often bring a multitude of externalities, primarily positive, which justify their growing application in urban planning. However, the intrinsic multifunctionality of NBS makes it highly complex for non-experts to fully capture the potential they can express. Therefore, more functional and effective tools are necessary to support the decision-making process. The goal of this paper is to propose a simplified Decision Support Tool (DST) which can guide planners and decision-makers in understanding which types of NBS and related co-benefits exist. The approach is built on previous studies and assessments, as well as case studies on existing platforms of projects such as ThinkNature (a former project of ISOCARP). To develop the DST, the research follows a three-step process. First, the existing classification schemes of NBS are reviewed, reducing them to an accessible level and applying the system to a range of suitable solutions with links to real-life cases documented in the existing databases. Secondly, two surveys are conducted: one addressing the needs of planners and decision-makers; another one utilising qualitative expert knowledge to assess the impact of co-benefits. Lastly, a simple prototype open-source tool is proposed. It provides different approaches assessing financial, accessibility, environmental, and social values and can, through multi-criteria assessments, be individualised for the prioritisation of NBS, co-benefits, and impacts. Particular focus will be on the financial dimension which is crucial for enabling investments. Consequently, the DST attempts an economic quantification of co-benefits, although restricted by the challenges of a comprehensive assessment of financial gains and losses across all dimensions of NBS and their lifetime. Comprehensively simplifying the understanding and quantification of NBS externalities is impossible; nevertheless, it must be tried. Any advancement can contribute significantly to more resilient and sustainable cities globally. While geographical, climate and social environments have to be considered, the approach can be replicated everywhere. Related to the Congress theme, any potential Post-Oil City includes the (re-)integration of nature. Expanding further, the connection to nature and lack thereof in today’s urban environments is increasingly seen as a crucial ingredient to develop functional and compassionate societies (e.g. Rifkins 2011), adding more layers of co-benefits, while the ongoing pandemic highlights the need for greenery and public space even more. Even if and when the situation in cities returns to the ‘new’ normal, long-term impacts (e.g. remote-working) will prevail. Thus, cities need to adapt and cater to the evolving needs of citizens instead of those of the economy to avoid the renaissance of less sustainable, less dense, rural conglomerations only connected digitally. Therefore, the opportunity to strengthen and advocate for NBS in cities and mainstream them into planning and policy practice is urgent and crucial for our cities of tomorrow.
