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Climate change is increasingly exerting pressure with intensified impacts in the short-, medium-, and long-term. Cities are highly vulnerable to the impacts of climate change, and it is recognized that they play a significant role in the European Strategy on adaptation to climate change. This study intends to develop a climate adaptation framework to identify effective measures that will be evaluated using a multi-urban area located in the north of Portugal, as a case study. The climate adaptation framework was developed following the Urban Adaptation Support Tool (AST), adapted to the Portuguese reality. The Weather Research and Forecasting (WRF) model was used to provide future projections with a high level of spatial resolution over the study area, increasing the accuracy of the identification of future climatic vulnerabilities. The results show a tendency for an increase of extreme weather events associated with the increase of both temperature and annual accumulated precipitation variables. A set of both urban and rural measures to promote a sustainable development path to climate adaptability and increase cities resilience to climate change are presented and discussed.

Climate change and the growth of urban populations are two of the main challenges facing Europe today. These issues are linked as climate change results in serious challenges for cities. Recent attention has focused on how urban surface-atmosphere exchanges of heat and water will be affected by climate change and the implications for urban planning and sustainability. In this study energy fluxes for Greater Porto area, Portugal, were estimated and the influence of the projected climate change evaluated. To accomplish this, the Weather Research and Forecasting Model (WRF) and the Surface Urban Energy and Water Balance Scheme (SUEWS) were applied for two climatological scenarios: a present (or reference, 1986-2005) scenario and a future scenario (2046-2065), in this case the Representative Concentration Pathway RCP8.5, which reflects the worst set of expectations (with the most onerous impacts). The results show that for the future climate conditions, the incoming shortwave radiation will increase by around 10%, the sensible heat flux around 40% and the net storage heat flux around 35%. In contrast, the latent heat flux will decrease about 20%. The changes in the magnitude of the different fluxes result in an increase of the net all-wave radiation by 15%. The implications of the changes of the energy balance on the meteorological variables are discussed, particularly in terms of temperature and precipitation., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The potential impacts of climate-induced changes in air pollution levels and its impacts on population health were investigated. The IPCC scenario (SRES A2) was used to analyse the effects of climate on future PM10 concentrations over Portugal and their impact on short-term population exposure and mortality. The air quality modelling system has been applied with high spatial resolution looking on climate changes at regional scale. To quantify health impacts related to air pollution changes, the WHO methodology for health impact assessment was implemented. The results point to 8% increase of premature mortality attributed to future PM10 levels in Portugal. The pollution episodes with daily average PM10 concentration above the current legislated value (50 μg·m⁻³) would be responsible for 81% of attributable cases. The absolute number of deaths attributable to PM10 under future climate emphasizes the importance of indirect effects of climate change on human health.

Abstract: Climate change alone may deeply impact air quality levels in the atmosphere because the changes in the meteorological conditions will induce changes on the transport, dispersion and transformation of air pollutants. The aim of this work was to evaluate the impact of climate change on the air quality over Europe and Portugal, using a reference year (year 1990) and a IPCC SRES A2 year (year 2100). The Hadley Centre global atmospheric circulation model (HadAM3P) was used to provide results for these two climatic scenarios, which were then used as synoptic forcing for the MM5-CHIMERE air quality modelling system. In order to assess the contribution of future climate change on O3 and PM concentrations, no changes in regional emissions were assumed and only climate change forcing was considered. The modelling results suggest that the O3 monthly mean levels in the atmosphere may increase almost 50μgm−3 across Europe in July under the IPCC SRES A2 scenario. In Portugal, this increase may reach 20μgm−3. The changes of PM10 monthly average values over Europe will depend on the region. The increase in PM10 concentrations during specific months could be explained by the average reduction of the boundary layer height and wind speed. [ABSTRACT FROM AUTHOR]

Different urban resilience measures, such as the increase of urban green areas and the application of white roofs, were evaluated with the WRF-SUEWS modelling system. The case study consists of five heat waves occurring in Porto (Portugal) urban area in a future climate scenario. Meteorological forcing and boundary data were downscaled for Porto urban area from the CMIP5 earth system model MPI-ESM, for the Representative Concentration Pathway RCP8.5 scenario. The influence of different resilience measures on the energy balance components was quantified and compared between each other. Results show that the inclusion of green urban areas increases the evaporation and the availability of surface moisture, redirecting the energy to the form of latent heat flux (maximum increase of + 200 W m − 2 ) rather than to sensible heat. The application of white roofs increases the solar radiation reflection, due to the higher albedo of such surfaces, reducing both sensible and storage heat flux (maximum reductions of − 62.8 and − 35 W m − 2 , respectively). The conjugations of the individual benefits related to each resilience measure shows that this measure is the most effective one in terms of improving the thermal comfort of the urban population, particularly due to the reduction of both sensible and storage heat flux. The obtained results contribute to the knowledge of the surface-atmosphere exchanges and can be of great importance for stakeholders and decision-makers. [ABSTRACT FROM AUTHOR]

Changes in climate and air pollutant emissions will affect future air quality from global to urban scale. In this study, regional air quality simulations for historical and future periods are conducted, with CAMx version 6.0, to investigate the impacts of future climate and anthropogenic emission projections on air quality over Portugal and the Porto metropolitan area in 2050. The climate and the emission projections were derived from the Representative Concentrations Pathways (RCP8.5) scenario. Modelling results show that climate change will impact NO 2 , PM10 and O 3 concentrations over Portugal. The NO 2 and PM10 annual means will increase in Portugal and in the Porto municipality, and the maximum 8-hr daily O 3 value will increase in the Porto suburban areas (approximately 5%) and decrease in the urban area (approximately 2%). When considering climate change and projected anthropogenic emissions, the NO 2 annual mean decreases (approximately 50%); PM10 annual mean will increase in Portugal and decrease in Porto municipality (approximately 13%); however PM10 and O 3 levels increase and extremes occur more often, surpassing the currently legislated annual limits and displaying a higher frequency of daily exceedances. This air quality degradation is likely to be related with the trends found for the 2046–2065 climate, which implies warmer and dryer conditions, and with the increase of background concentrations of ozone and particulate matter. The results demonstrate the need for Portuguese authorities and policy-makers to design and implement air quality management strategies that take climate change impacts into account. [ABSTRACT FROM AUTHOR]

Abstract: In a future climate scenario forest fire activity over Portugal will substantially increase and consequently area burned and forest fire emissions to the atmosphere are also expected to increase. This study investigated the impact of future forest fire emissions on air quality over Portugal under the IPCC SRES A2 scenario. Reference and future climate change scenarios were simulated using the MM5/CHIMERE air quality modelling system, which was applied over Europe and over Portugal, using nesting capabilities. The initial and boundary conditions were provided by the HadAM3P model simulations for the reference and the future climate. The forest fire emissions were estimated using a methodology, which included the selection of emission factors for each pollutant, burning efficiency, fuel loads and the predicted area burned. These emissions were added to the simulation grid using specific parameterizations for their vertical distribution. Modelling results for Portugal pointed out that future forest fire activity will increase the O3 concentrations of almost 23 μg m−3 by 2100 but a decrease of approximately 6 μg m−3 is detected close to the main forest fire locations. Future forest fire emissions will also impact the PM10 concentrations over Portugal with increases reaching 20 μg m−3 along the Northern coastal region in July. The highest increases are estimated over the north and centre of Portugal where the area burned projections in future climate are higher. [Copyright &y& Elsevier]

Abstract: Results from general circulation models suggest that the increase of forest fire activity at the global scale will be one of the impacts of climate change. As attention shifts to regional climate further spatial resolution is needed to handle the forcings and circulations that occur at smaller scales. One of the available techniques to assess the impact of climate change on fire activity at the regional scale is the dynamical downscaling between global climate models and regional models. In the present work, the impact of climate change on fire danger at the regional scale was examined by means of dynamical downscaling between a general circulation model (MUGCM) and a regional meteorological model (MM5). A Southern European country, Portugal, was selected as case-study since general circulation models predict significant surface air temperature increases over Southern and Mediterranean Europe. Present and future climates, centred in 1990 and 2050, respectively, were obtained using daily data previously simulated by MUGCM. Climate change signals on temperature and precipitation derived from the MUGCM ensemble simulations were analysed using spatial averages over the Iberian Peninsula and cluster analysis applied over Portugal. For the Iberian Peninsula, a positive trend for temperature for all seasons, with higher variability for the winter months, was obtained. Over Portugal, for the future climate, the average winter temperature is expected to be higher. Precipitation increases are simulated for the end of autumn/beginning of winter, and negative changes are expected for the end of winter/beginning of spring and beginning of summer. The cluster analysis revealed important temporal changes on the meteorological variables which may be relevant for fire management planning, namely a longer fire season over Portugal is expected. The spatial refinement of the projected climate change impacts on the fire weather risk over Portugal was performed through numerical downscaling between MUGCM and MM5. The MM5 outputs, at 10 km resolution, were used to estimate the Canadian Fire Weather Index (FWI) System components. Results show higher FWI values in the beginning of summer for the 2050 scenario. An increase of the maximum values of the Drought Code (DC) in the inner part of Portugal was also detected. An increase in the total area burned is anticipated, with the consequent increase of pollutants emissions. [Copyright &y& Elsevier]

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, NO 2 and O 3 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 NO 2 (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 NO 2 , by around −1% and −3%, respectively. The O 3 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 O 3 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. • Cities must become resilient to be able to deal with future air pollution. • Different "green" measures were studied using the WRF-CHIMERE modelling setup. • Green roofs, white roofs and white surfaces increases PM10 and NO 2 concentrations. • Green urban areas decreases PM10 and NO 2 concentrations and increases O 3 levels. • Double effects were found, showing the need of knowledge-based urban planning. [ABSTRACT FROM AUTHOR]