Climate change (CC) is the main global threat of this century as the foreseen increased frequency, intensity, and/or duration of extreme weather events will impact natural and human systems. CC is expected to influence urban living conditions, in particular, air pollution and urban heating that cause high morbidity and mortality rates and, hence, challenging cities to adopt mitigation and adaptation measures. One of the suggested measures is Nature-based solutions (NBS). The main objective of this work was to assess the impact of NBS on urban heat and air quality for present and future climate scenarios to evaluate the effectiveness of these solutions for climate change adaptation. Three European urban areas with different characteristics and challenges were chosen as case studies: Eindhoven (Netherlands), Genova (Italy) and Tampere (Finland). An extensive assessment of climate, atmospheric emissions, and air quality showed that the case study areas had meaningful air quality improvement over the last decade (except for ozone concentrations). However, cities still struggle to comply with newer and more rigorous air quality limit or guidance values. Temperature projections obtained with the WRF model, at 1 km x 1 km spatial resolution, based on the RCP4.5 scenario, indicated an overall warming, particularly in Eindhoven. Multiple NBS scenarios were tested for the case studies, using the WRF-chem chemical transport model. The results were very similar between cities and scenarios, demonstrating that NBS were more effective in reducing urban heat than improving air quality. Based on 1-year-long air quality simulations for current and future climates, a stronger impact of NBS was seen during warmer months with urban heat decreasing up to -1 ºC. The air quality impact was low, with a predisposition for nitrogen dioxide increase (P90 = 3.40 μg/m3) and a decrease in ozone concentration (P10 = -2.20 μg/m3). Despite the effects of NBS, overall, the changes promoted by CC were more impactful. This study highlights the effectiveness of NBS in mitigating urban heat, thereby improving citizens' overall health and well-being. This study also advises about the need for NBS to be context-adapted and emphasizes the importance of long-term planning to account for climate change impacts, providing a framework for future NBS projects.

Seagrasses are one of the most threatened ecosystems and have been declining worldwide. These ecosystems provide important ecological services to the marine environment and ecosystem services of high value, such as their role in climate regulation (long-term carbon storage in sediments and plants). Given the increase in greenhouse gases and the importance of these ecosystems for climate change mitigation, contributing to the reduction of carbon dioxide (CO₂) in the atmosphere, it has become important to amplify the scale of restoration of these ecosystems, as well as their conservation. The present study at Ria de Aveiro (as case of study), aimed at (1) to promote the carbon storage capacity of seagrass meadows through restoration actions; (2) to assess the contribution of restoration actions to increase carbon storage in the Zostera noltei meadows; (3) to contribute to the objectives defined by the United Nations Decade for the Restoration of Ecosystems (2021-2030) and the EU Nature Restoration Law. This study provides a spatial (Murtosa, Antuã, Aveiro and Ílhavo) and temporal (2023 to 2024) assessment of the potential of seagrass (Zostera noltei) restoration for Blue Carbon storage at Ria de Aveiro, Portugal. Seagrass donor meadows were selected considering the seagrass coverage, healthy conditions and the distance to the restoration site. The transplant covers an area of 100 m² and were monitored in situ through photographs to assess the status and coverage of Zostera noltei using a GoPro Hero 6 and a Drone DJI Mavic 3 Classic. At each site PVC hand-corer were collected for sediment characterisation and Blue Carbon assessment. Antuã was the most successfully transplanted site, associated with fine sediments, higher organic matter, carbonates and organic carbon contents, while Murtosa was the least successful of the four sites, associated with sandier sediments, and in turn was the site where erosion occurred. C and N stocks were estimated and were higher in the Donor meadow compared to the Bare bottom, with the exception of N stock in Ílhavo. The potential of restoration implies long-term monitoring. This seagrass restoration project in the Ria de Aveiro offers a contribution to conservation and restoration, preventing the loss and degradation of habitats and improving the functioning and services of ecosystems, to achieve the goals set by the United Nations Decade for the Restoration of Ecosystems (2021-2030) and the EU Nature Restoration Law, as well as the contribution to the inventory of blue carbon.

Most cities are growing and becoming more densely populated, resulting in land use changes, which promote an increase of urban heating. Nature-based solutions (NBS) are considered sustainable, cost-effective and multi-purpose solutions for these problems. While various studies assess the effects of NBS on urban heat or urban sprawl/compaction, no studies assess their cumulative effect. The main objective of this study is to assess the short-term and medium- to long-term impacts of NBS on urban heat fluxes, taking as a case study the city of Eindhoven in The Netherlands. An integrated modelling approach, composed of a coupled meteorological and urban energy balance model (WRF-SUEWS) and an hedonic pricing simulation model (SULD), is used to assess urban heat fluxes and urban compaction effects, respectively. Results show that, in the short-term, NBS have a local cooling effect due to an increase in green/blue spaces and, in the medium to long-term, an urban compaction effect due to attraction of residents from peripheral areas to areas surrounding attractive NBS. This study provides evidence that NBS can be used to reduce the effects of urban heating and urban sprawl and that an integrated modelling approach allows to better understand its complete effects.

The effect of different “green” measures, such as the increase of urban green areas, the application of green roofs and the increase of surfaces albedo on urban air quality were evaluated with the WRF-CHIMERE modelling system. In order to account for the heterogeneity of urban areas, a single layer urban canopy model was coupled to the WRF model. The case study consists of a heat wave occurring in the Porto (Portugal) urban area in a future climate scenario, considering the Representative Concentration Pathway RCP8.5. The influence of the selected measures on PM10, NO2 and O3 concentrations was quantified and compared with a control run (without measures) simulation scenario. The results revealed that all the measures are able to mitigate the effects of heat waves by reducing the air temperature between −0.5 °C and −1 °C (maximum differences for the mean of the episode). Positive and negative effects were found in terms of air quality. The implementation of green roofs and the increase of surfaces albedo promoted an overall increase of PM10 (between +0.6% and +1.5%) and NO2 (between +0.8% and 3.5%) concentrations, which are closely related to a decrease of vertical mixing in the urban boundary layer. The increase of green urban areas promoted an overall decrease (on average) of both PM10 and NO2, by around −1% and −3%, respectively. The O3 levels increased with the increase of urban green areas, mostly located over the Porto urban area. Slight differences were promoted by the implementation of green roofs. For the increase of surfaces albedo, both increases and decreases of O3 concentrations were observed. The obtained results contribute to the knowledge of the chemical composition of the urban atmosphere and can be of great importance for stakeholders and decision-makers to deal with climate change impacts.

The increase in the frequency and intensity of heat waves is a growing challenge to public health, particularly in urban areas, where the effect of Urban Heat Islands (ICU) is most pronounced. Nature-Based Solutions (NBS) play an important role in the adaptation of cities to this phenomenon, although there are still gaps in the evaluation of their thermal performance in the medium and long term. The present study analyzes the Dr. Luís César Pereira Urban Park, located in the Lisbon Metropolitan Area, focusing on the contribution of trees to microclimatic cooling. The Normalized Difference Vegetation Index (NDVI), the Normalized Difference Water Index (NDWI) and the Surface Temperature (LST) were applied on summer days and during extreme heat episodes, in the years 2022, 2023 and 2024. The results show a thermal reduction of about 2 °C in the perimeter of the Park up to 500m. However, the absence of thermoregulatory influence of the Tagus River, its location within a dense urban area and the lack of data on air temperature make it difficult to confirm the formation of a Park Cool Area. While the vegetation generally exhibits good vitality and an absence of water stress, temperatures above 40 °C were recorded in wooded areas. This reflects limitations associated with the inadequate shading provided by certain species, the reduced effectiveness of the trees during extreme episodes, and the untapped potential of the Ribeira de Santa Sofia, whose seasonal characteristics hinder thermal regulation. Even so, the park reveals a significant capacity to promote thermal comfort, which is particularly relevant considering that about 80% of the population living within a 300 m radius is considered as vulnerable to heat waves.

Although covering less than 1% of the land surface, extraction activities have long‐lasting impacts on local ecosystems, inevitably damaging biological diversity and depleting ecosystem services. Many extractive companies are now aware of their impacts and, while pressured by society, demand concrete solutions from researchers to reverse the effects of exploitation and restore biodiversity and ecosystems services. In this article, we compile and synthesize the contributions of the latest available research on quarry restoration. We depict and discuss some of the most pressing issues regarding (1) the challenges of restoring quarries; (2) the opportunities for biodiversity and ecosystem services delivery; and (3) outline further research addressing current gaps. We conclude that quarries pose different abiotic and biotic constraints that act interdependently, hampering the attainment of effective restoration if considered solely. Such constraints need to be addressed holistically to lastly encourage the self‐sustainability of the system by reinstating ecological processes. However, a restored site does not have to specifically mimic the pristine situation, as under certain conditions alternative approaches may uphold valuable natural assets contributing to the conservation of rare, restricted, or protected species and habitats.

The urban heat island effect creates warmer and drier conditions in urban areas than in their surrounding rural areas. This effect is predicted to be exacerbated in the future, under a climate change scenario. One way to mitigate this effect is to use the urban green infrastructure as a way to promote the cooling island effect. In this study we aimed to model, with a high spatial resolution, how Mediterranean urban parks can be maximized to be used as cooling islands, by answering the following questions: i) which factors influence the cooling effect and when?; ii) what type of green spaces contributes the most to the cooling effect?; iii) what is the cooling distance of influence? To answer these questions we established a sampling design where temperature and relative humidity were measured in different seasons, in locations with contrasting characteristics of green and grey cover. We were able to model the effect of green and grey spaces in the cooling island effect and build high spatial resolution predicting maps for temperature and relative humidity. Our study showed that even green spaces with reduced areas can regulate microclimate, alleviating temperature by 1-3 °C and increasing moisture by 2-8%, on average. Green spaces with a higher density of trees were more efficient in delivering the cooling effect. The morphology, aspect and level of exposure of grey surfaces to the solar radiation were also important features included in the models. Green spaces influenced temperature and relative humidity up to 60 m away from the parks' limits, whereas grey areas influenced in a much lesser range, from 5 m up to 10 m. These models can now be used by citizens and stakeholders for green spaces management and human well-being impact assessment.

Purpose: The study aims to assess the implementation of an intervention program that combines nature-based solutions with an environmental citizenship pedagogical approach for pre-service teachers. The research questions revolve around the educational potentials and challenges of this intervention. To our knowledge, no previous studies resorted to this combination to organize courses for initial teacher training. Design/methodology/approach: For this qualitative and interpretative case study, data was obtained through focus groups. 30 pre-service teachers of the Basic Education Course (training kindergarten and primary school teachers) in Portugal participated in the intervention. The transcripts of the focus groups’ content were subjected to categorical qualitative content analysis. Findings: According to the participants, the implemented approach contributed to the development of a better understanding of the complexity of the environmental issues addressed, and of critical thinking skills. The pre-service teachers recognized the educational potential of nature-based solutions in the promotion of their environmental citizenship and activist competences and of the pedagogical knowledge necessary for its implementation.

Nature-based solutions (NbS) are increasingly recognized as strategic alternatives and complements to grey infrastructure for addressing water-related challenges in the context of climate change, urbanization, and biodiversity decline. This article presents a critical, theory-informed review of the state of NbS implementation in European water management, drawing on a structured synthesis of empirical evidence from regional case studies and policy frameworks. The analysis found that while NbS are effective in reducing surface runoff, mitigating floods, and improving water quality under low- to moderate-intensity events, their performance remains uncertain under extreme climate scenarios. Key gaps identified include the lack of long-term monitoring data, limited assessment of NbS under future climate conditions, and weak integration into mainstream planning and financing systems. Existing evaluation frameworks are critiqued for treating NbS as static interventions, overlooking their ecological dynamics and temporal variability. In response, a dynamic, climate-resilient assessment model is proposed—grounded in systems thinking, backcasting, and participatory scenario planning—to evaluate NbS adaptively. Emerging innovations, such as hybrid green–grey infrastructure, adaptive governance models, and novel financing mechanisms, are highlighted as key enablers for scaling NbS. The article contributes to the scientific literature by bridging theoretical and empirical insights, offering region-specific findings and recommendations based on a comparative analysis across diverse European contexts. These findings provide conceptual and methodological tools to better design, evaluate, and scale NbS for transformative, equitable, and climate-resilient water governance.

This study aimed to investigate the potential use of the microalgae Chlorella sorokiniana and Scenedesmus quadricauda for the bioremediation of olive mill wastewater (OMW), which is a major environmental issue and a waste product of olive oil production. The study investigated the effects of different dilutions (10% and 50%) of OMW on the growth of the microalgae and their ability to remove the phenolic component hydroxytyrosol (OH-Tyr) and enhance their antioxidant properties. The results indicated that, although the growth on OMW was not enhanced, both microalgae strains were able to remove OH-Tyr from OMW, with Chlorella sorokiniana showing higher removal efficiency than Scenedesmus quadricauda. Moreover, the antioxidant activity of the microalgal extracts increased after 96 h of exposure to OMW. These findings suggest that microalgae-based treatment of OMW could be a promising approach for the bioremediation of this waste product and the production of value-added products. Overall, the use of microalgae for the treatment of OMW could provide a sustainable solution for the management of this waste product while generating potential economic benefits for olive producers.