Evaluating the Impact of Nature-Based Solutions: A Handbook for Practitioners

The Handbook aims to provide decision-makers with a comprehensive NBS impact assessment framework, and a robust set of indicators and methodologies to assess impacts of nature-based solutions across 12 societal challenge areas: Climate Resilience; Water Management; Natural and Climate Hazards; Green Space Management; Biodiversity; Air Quality; Place Regeneration; Knowledge and Social Capacity Building for Sustainable Urban Transformation; Participatory Planning and Governance; Social Justice and Social Cohesion; Health and Well-being; New Economic Opportunities and Green Jobs. Indicators have been developed collaboratively by representatives of 17 individual EU-funded NBS projects and collaborating institutions such as the EEA and JRC, as part of the European Taskforce for NBS Impact Assessment, with the four-fold objective of: serving as a reference for relevant EU policies and activities; orient urban practitioners in developing robust impact evaluation frameworks for nature-based solutions at different scales; expand upon the pioneering work of the EKLIPSE framework by providing a comprehensive set of indicators and methodologies; and build the European evidence base regarding NBS impacts. They reflect the state of the art in current scientific research on impacts of nature-based solutions and valid and standardized methods of assessment, as well as the state of play in urban implementation of evaluation frameworks

An expanded framing of ecosystem services is needed for a sustainable urban future

Urban activities are an important driver of ecosystem services decline. Sustainable urbanisation necessitates anticipating and mitigating these negative socio-ecological impacts, both within and beyond city boundaries. There is a lack of scalable, dynamic models of changes to ecosystems wrought by urban processes. We developed a system dynamics model, ESTIMUM, to predict locations, types, and magnitude of changes in ecosystem services. We tested the model in Lisbon (Portugal) under four specific urban development scenarios – a base case scenario and three local sustainability-driven scenarios – to the year 2050. Our results show that urban sustainability policies focused on reducing impacts within Lisbon can be undermined by increased impacts in the extended regions that supply resources to the city. In particular, carbon sequestration from urban greening pales in comparison to growing greenhouse gases from the consumption of food, energy and construction materials. We also find that policies targeted at these extended environmental impacts can be much more effective than those with a limited focus on the urban form. For example, dietary shifts could support positive changes outside that city to increase global climate regulation by 54% compared to a mere 1% increase through intensive urban greening. This highlights the urgent need for a reframing of urban sustainability in policy and scholarly circles from city-centric focus towards an expanded multi-scalar conceptualisation of urban sustainability that accounts for urban impacts beyond the city boundaries

Introduction

Human life on Earth depends on ecosystems. This is the main message conveyed by the concept of ecosystem services (ES), which has gained an ever-increasing attention in the scientific (McDonough et al. 2017) and policy debate (e.g., CBD 2011; European Commission 2006, 2010) of the last two decades. The success of the term ‘ecosystem services’ is arguably due to its encompassing all “the direct and indirect contributions of ecosystems to human wellbeing” (TEEB 2010a), thus providing a comprehensive framework to describe the multiple relationships between humans and nature.QC 20191001</p