Globally, flood events are considered the costliest natural hazard. Changes in precipitation patterns and large areas of impervious surfaces in urban environments are increasing the sensitivity of these systems to runoff production. At the same time, projected global sea-level rise may further increase the frequency of compound flooding due to simultaneous storm surge, sea-level rise and pluvial runoff that cause vast socio-economic and ecological impacts to coastal cities. In this context, over the last decade, the role of Nature-Based Solutions (NBS) has been recognised to support climate change adaptation by addressing ideas of multi-functionality, non-linearity and heterogeneity in urban design. Thus, increasing awareness about NBS benefits increases the willingness to accept these solutions. However, empirical evidence of NBS effectiveness at the urban catchment scale is still subject to debate. This study develops a spatial biophysical-economic framework that allows for the integrated assessment of NBS flood risk mitigation impacts, costs and benefits in the face of climate change, combining the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, benefit transfer methods and Geographic Information System (GIS) tools. Specifically, the InVEST Urban Flood Risk Mitigation model was used to assess the biophysical impacts of NBS on urban pluvial flood risk, benefit-transfer methods were used to evaluate the economic implications of such solutions, and GIS was used to integrate and map biophysical impacts and economic implications. For the case of the coastal lagoon city of Aveiro (Portugal), NBS scenarios of green roofs and bioswales under current and future climate conditions were assessed. The main findings of this study show that green roofs scenarios would save 32 % of the flood damages to buildings and infrastructures every year, while bioswales help save only 0.1 %. Moreover, green roofs implementation provides larger benefits in the future climate scenario (representative concentration pathway - RCP - 4.5). The findings confirm the extent to which knowledge on NBS benefits and costs is partial and uncertain, thus requiring constant progress through biophysical-economic assessment to support an evolutive decision making process in climate adaptation planning.

The Ovar coastline is characterized as one of the coastal areas with the highest vulnerability and risk of erosion in the Portuguese coast. The high-energy coast is further threatened by a permanent sediment deficit of anthropic origin, as well as sea level rise due to climate change. It is essential to define modern coastal adaptation strategies to minimize the impacts of these issues on the local communities, while considering social, environmental, and economic factors. It is in this territory that the INCCA project’s case study is located, involving stakeholders with technical, scientific, and operational knowledge in the co-management of the coastal stretch. In the scope of the involvement intended for the project’s development, five participatory events were held, involving local authorities, civil protection, public entities, academia, and the general community. These events allowed a multidisciplinary and multi-stakeholder analysis of the challenges and possible solutions to mitigate coastal erosion, representing the definition of a shared vision for the coastline’s future in this municipality. This work presents the main results of this participatory process as well as reflections on the importance of active citizenship instruments and stakeholder involvement for integrated coastal management in the 21st century.

Global climate change and growing urbanization pose a threat to both natural and urban ecosystems. In these, one of the most impacted elements is water, which is responsible for a large variety of ecosystem services and benefits to society. Mathematical models can be used to simulate the implementation of Nature-Based Solutions (NBSs), thus helping to quantify these issues in a practical and efficient manner. This paper presents a rapid review of literature in which the effects of NBS on water quality were assessed with the help of modelling methods. It was found that only 14 papers deal with the topic in regard to NBSs. Most of these papers were published in European countries, using Nitrogen and/or Phosphorus as the studied water quality indicators and focusing predominantly on wetlands. The literature suggests that NBS can positively impact surface water quality, even under future climate conditions, while being a justified investment from an economic standpoint. It is suggested that more information is required in order to expand the evidence base on the effectiveness of NBS for water quality improvement as well as to develop better and more standardized methods to model NBS impacts on water quality.

This article explores general concepts related to the diffusion of innovations theory (DoI) and its use regarding the adoption of nature-based solutions, specifically green roofs, in urban areas by private house/property owners in the city of Eindhoven (Netherlands). Given the gap in knowledge on the potential for the adoption of green roofs by private house/property owners as well as barriers and enablers to their implementation from the DoI perspective, we used a model for predicting the adoption of innovations (ADOPT). Results show that the predicted peak adoption level is 3% and that the time to peak adoption level is 17 years. However, the level of adoption can be significantly enhanced by increasing profit benefit (i.e., cost savings) in the years that they are used (+19 percent points adoption), reducing risk exposure (+17 percent points adoption), and improving ease and convenience (+15 percent points adoption), while the time to peak adoption level can be reduced by enhancing relevant and existing skills and knowledge (−3 years), simplifying trialability and innovation complexity (−2 years), and increasing observability (−1 year). Hence, key factors affecting the adoption of green roofs by private house/property owners have been identified, contributing to the formulation of urban climate change adoption strategies.

The Coronavirus Disease 2019 (COVID-19) pandemic that spread through the world in 2020 had a major effect on academia. Research projects relying on participatory methods and action research approaches were especially harmed by the restrictions and changes the situation imposed. This study performs a rapid literature review to identify common themes in the narratives of published studies concerning the difficulties of carrying-out participatory research during the COVID-19 pandemic. Perceptions and experiences of the authors of these studies are compiled and summarized. Additionally, insights and lessons learned from two projects in which the authors of this study participated are discussed and used to establish a comparison with the common challenges found in the literature. Over 90% of authors experienced challenges related to digitalization and methodological changes, 70% encountered difficulties with organizational and operational aspects of research, and over 30% felt that personal challenges, as well as issues with participatory aspects of research, were significant. On a positive note, almost 40% of authors from our sample recognize that the pandemic also brought unexpected benefits, such as a reduction in logistical expenses, and the creation of new opportunities for participation. This study adds to the growing body of literature regarding the effects of the COVID-19 pandemic on the research community. Additionally, it comments on the adaptation of participatory action research methods for added sustainability and social inclusion in the face of global crises.