Impact Of Future Climate Change Research Articles

Anticipating and Adapting to the Future Impacts of Climate Change on the Health, Security and Welfare of Low Elevation Coastal Zone (LECZ) Communities in Southeastern USA

Low elevation coastal zones (LECZ) are extensive throughout the southeastern United States. LECZ communities are threatened by inundation from sea level rise, storm surge, wetland degradation, land subsidence, and hydrological flooding. Communication among scientists, stakeholders, policy makers and minority and poor residents must improve. We must predict processes spanning the ecological, physical, social, and health sciences. Communities need to address linkages of (1) human and socioeconomic vulnerabilities; (2) public health and safety; (3) economic concerns; (4) land loss; (5) wetland threats; and (6) coastal inundation. Essential capabilities must include a network to assemble and distribute data and model code to assess risk and its causes, support adaptive management, and improve the resiliency of communities. Better communication of information and understanding among residents and officials is essential. Here we review recent background literature on these matters and offer recommendations for integrating natural and social sciences. We advocate for a cyber-network of scientists, modelers, engineers, educators, and stakeholders from academia, federal state and local agencies, non-governmental organizations, residents, and the private sector. Our vision is to enhance future resilience of LECZ communities by offering approaches to mitigate hazards to human health, safety and welfare and reduce impacts to coastal residents and industries.

Predicting the Impact of Future Land Use and Climate Change on Potential Soil Erosion Risk in an Urban District of the Harare Metropolitan Province, Zimbabwe

Monitoring urban area expansion through multispectral remotely sensed data and other geomatics techniques is fundamental for sustainable urban planning. Forecasting of future land use land cover (LULC) change for the years 2034 and 2050 was performed using the Cellular Automata Markov model for the current fast-growing Epworth district of the Harare Metropolitan Province, Zimbabwe. The stochastic CA–Markov modelling procedure validation yielded kappa statistics above 80%, ascertaining good agreement. The spatial distribution of the LULC classes CBD/Industrial area, water and irrigated croplands as projected for 2034 and 2050 show slight notable changes. For projected scenarios in 2034 and 2050, low–medium-density residential areas are predicted to increase from 11.1 km2 to 12.3 km2 between 2018 and 2050. Similarly, high-density residential areas are predicted to increase from 18.6 km2 to 22.4 km2 between 2018 and 2050. Assessment of the effects of future climate change on potential soil erosion risk for Epworth district were undertaken by applying the representative concentration pathways (RCP4.5 and RCP8.5) climate scenarios, and model ensemble averages from multiple general circulation models (GCMs) were used to derive the rainfall erosivity factor for the RUSLE model. Average soil loss rates for both climate scenarios, RCP4.5 and RCP8.5, were predicted to be high in 2034 due to the large spatial area extent of croplands and disturbed green spaces exposed to soil erosion processes, therefore increasing potential soil erosion risk, with RCP4.5 having more impact than RCP8.5 due to a higher applied rainfall erosivity. For 2050, the predicted wide area average soil loss rates declined for both climate scenarios RCP4.5 and RCP8.5, following the predicted decline in rainfall erosivity and vulnerable areas that are erodible. Overall, high potential soil erosion risk was predicted along the flanks of the drainage network for both RCP4.5 and RCP8.5 climate scenarios in 2050.

Impacts of future climate and land cover changes on landslide susceptibility: regional scale modelling in the Val d’Aran region (Pyrenees, Spain)

It is widely accepted that future environmental changes will affect rainfall-induced shallow slides in high-mountain areas. In this study, the Val d’Aran region located in the Central Pyrenees was selected to analyze and quantify the impacts of land use and land cover (LULC) and climate changes on regional landslides susceptibility. We analyzed 26 climate models of the EURO-CORDEX database focussing on the future rainfall conditions. The IDRISI TerrSet software suite was used to create the future LULC maps. These two inputs were analyzed individually and in a combined way defining 20 different scenarios. All these scenarios were incorporated in a physically based stability model to compute landslides susceptibility maps. The results showed that both environmental conditions will considerably change in the future. The daily rainfall will increase between 14 and 26% assuming a return period of 100 years. This intensification of precipitation will produce an overall decrease of the stability condition in the study area. Regarding the LULC prediction, the forest area will significantly increase, while in particular grassland, but also shrubs decrease. As a consequence, the overall stability condition improves, because the root strength is higher in forest than in grassland and shrubs. When we analyzed the combined impacts, the results showed that the positive effect of LULC changes is larger than the negative influence of rainfall changes. Hence, when combining the two aspects in the future scenarios, the stability condition in the study area will improve.

Seasonal variability in multimedia transport and fate of benzo[a]pyrene (BaP) affected by climatic factors

The impact of meteorological factors on the transport behavior and distribution of volatile and semi-volatile organic pollutants has become an area of increasing concern. Here, we analyzed seasonal variation in climatic variables including wind, temperature, and precipitation to quantitatively assess the impact of these factors on the multimedia transport and fate of BaP in the continental region of China using a Berkeley-Trent (BETR) model. The advective rates of air exhibited an increasing trend of autumn (1.830 mol/h) < summer (1.975 mol/h) < winter (2.053 mol/h) < spring (2.405 mol/h) in association with increasing wind speed, indicating that lower atmospheric BaP concentrations are present in regions with high wind speeds and advective rates. The air-soil transport rates (0.08–45.55 mol/h) in winter were higher than in summer (0.07–32.41 mol/h), while low winter temperatures accelerate BaP accumulation in terrestrial ecosystems due to cold deposition. Cold deposition effects were more evident in northern regions than in southern regions. Further, increasing precipitation enhanced air-soil and soil-freshwater transport rates with the correlation coefficients of r = 0.445 and r = 0.598 respectively, while decreasing the air-vegetation transport rates (r = 0.475), thereby contributing to the accumulation of BaP in soils and freshwaters. In the light of the potential dispersion of BaP pollution at regional and global scales affected by these key climatic factors, this indirectly indicated the impact of future climate change on the BaP transport. Thus, flexible policy interventions should be enacted to slow future climate change.

Impact of future climate change on malaria in West Africa

Understanding the regional impact of future climate change is one of the major global challenges of this century. This study investigated possible effects of climate change on malaria in West Africa in the near future (2006–2035) and the far future (2036–2065) under two representative concentration pathway (RCP) scenarios (RCP4.5 and RCP8.5), compared to an observed evaluation period (1981–2010). Projected rainfall and temperature were obtained from the coordinated regional downscaling experiment (CORDEX) simulations of the Rossby Centre Regional Atmospheric regional climate model (RCA4). The malaria model used is the Liverpool malaria model (LMM), a dynamical malaria model driven by daily time series of rainfall and temperature obtained from the CORDEX data. Our results highlight the unimodal shape of the malaria prevalence distribution, and the seasonal malaria transmission contrast is closely linked to the latitudinal variation of the rainfall. Projections showed that the mean annual malaria prevalence would decrease in both climatological periods under both RCPs but with a larger magnitude of decreasing under the RCP8.5. We found that the mean malaria prevalence for the reference period is greater than the projected prevalence for 6 of the 8 downscaled GCMs. The study enhances understanding of how malaria is impacted under RCP4.5 and RCP8.5 emission scenarios. These results indicate that the southern area of West Africa is at most risk of epidemics, and the malaria control programs need extra effort and help to make the best use of available resources by stakeholders.

Biomorphogenic Feedbacks and the Spatial Organization of a Dominant Grass Steer Dune Development

Nature-based solutions to mitigate the impact of future climate change depend on restoring biological diversity and natural processes. Coastal foredunes represent the most important natural flood barriers along coastlines worldwide, but their area has been squeezed dramatically because of a continuing urbanization of coastlines, especially in Europe. Dune development is steered by the development of vegetation in interaction with sand fluxes from the beach. Marram grass (Calamagrostis arenaria, formerlyAmmophila arenaria) is the main dune building species along most European coasts, but also in other continents where the species was introduced. Engineering of coastal dunes, for instance by building dunes in front of dikes, needs to be based on a solid understanding of the species’ interactions with the environment. Only quantitative approaches enable the further development of mechanistic models and coastal management strategies that encapsulate these biomorphogenic interactions. We here provide a quantitative review of the main biotic and physical interactions that affect marram grass performance, their interactions with sand fluxes and how they eventually shape dune development. Our review highlights that the species’ spatial organization is central to dune development. We further demonstrate this importance by means of remote sensing and a mechanistic model and provide an outlook for further research on the use of coastal dunes as a nature-based solution for coastal protection.

Plausible changes in wheat‐growing periods and grain yield in China triggered by future climate change under multiple scenarios and periods

AbstractWheat is one of the most common and productive crops in the world, and the growth and production of wheat are sensitive to climate change. Climate change affects wheat phenology by influencing sowing/maturity dates and the duration of growing stages, and ultimately affects the grain yield. Reliable prediction of changes in wheat yield is significant for maintaining global food security. However, studies addressing the potential impact of crop phenology changes on grain yield are rarely reported, which is a big challenge. Using the CERES‐Wheat model and first‐order differential equation models, we quantified the impact of future climate change on wheat phenology and grain yield for two periods (P1: 2011–2040; P2: 2041–2070) under three representative concentration pathways (RCP2.6, RCP4.5, RCP8.5) in China's two main wheat‐growing areas (Northwest Spring Wheat‐Growing Area (NWSWA) and Huang–Huai–Hai Winter Wheat‐Growing Area (HHWWA)); the baseline period was 1981–2010. Accumulated thermal time during the whole growing period (WGP) tends to significantly increase in NWSWA and HHWWA under all RCPs and periods. This rising accumulated thermal time will reduce the time to anthesis and maturity and shorten the vegetative growing period (VGP), reproductive growing period (RGP), and the WGP. In P2, spring wheat grain yield is projected to diminish by a regional average of 2.67% for RCP2.6, 4.07% for RCP4.5, and 5.66% for RCP8.5, which is dominated by the lower accumulated solar radiation during the VGP in NWSWA. Additionally, for the winter wheat grain yield in HHWWA in P2, its grain yield reduction is projected to decline by 4.8% (RCP2.6), 7.9% (RCP4.5), and 9.8% (RCP8.5), which is caused by increasing accumulated thermal time in the VGP. These results suggest that breeding high‐temperature‐tolerant varieties with high calorie requirements is an adaptive strategy to mitigate the negative impact of climate change on wheat yield in the study areas.

Prolonged impacts of extreme precipitation events weakened annual ecosystem CO2 sink strength in a coastal wetland

It remains unclear whether coastal wetlands could maintain the expected carbon sink role since extreme climate events are predicted to occur more frequently under future climate change. Among these extreme events, extreme precipitation may cause significant changes in ecosystem carbon stocks in coastal wetlands. However, the impacts of extreme precipitation events on carbon cycle processes and the mechanisms responsible for associated changes in the ecosystem carbon balance remain uncertain. To address this issue, we investigated the effects of extreme precipitation events on the ecosystem carbon dioxide (CO2) budget based on a 10-year eddy covariance dataset (2010-2019) at a coastal wetland in the Yellow River Delta. Results showed that this coastal wetland was a stable sink for CO2, with the annual net ecosystem CO2 exchange (NEE) ranged between -94.49 and -240.70 g C m−2 yr−1. Meanwhile, the interannual variability of the ecosystem CO2 sink strength in the dry stage was linked to the vegetation condition, and it was strongly affected by extreme precipitation events in the wet stage. During the wet stage, there was a clear trend of less negative daily NEE (i.e., lower CO2 uptake rate) in the years with extreme precipitation events occurring (extreme years) than in normal years, leading to the wet stage cumulative CO2 uptake being 56% lower in extreme years. Eventually, the coastal wetland became a weaker annual CO2 sink due to the prolonged impact of the extreme precipitation event. This research provides a timely study of the effect of extreme precipitation on ecosystem CO2 budget in coastal wetlands and should be of value to researchers attempting to assess the future impact of climate change on coastal ecosystems.

Climate change may interact with nitrogen fertilizer management leading to different ammonia loss in China's croplands.

Despite research into the response of ammonia (NH3 ) volatilization in farmland to various meteorological factors, the potential impact of future climate change on NH3 volatilization is not fully understood. Based on a database consisting of 1063 observations across China, nonlinear NH3 models considering crop type, meteorological, soil and management variables were established via four machine learning methods, including support vector machine, multi-layer perceptron, gradient boosting machine and random forest (RF). The RF model had the highest R2 of 0.76 and the lowest RMSE of 0.82 kg NH3 -N ha-1 , showing the best simulation capability. Results of model importance indicated that NH3 volatilization was mainly controlled by total input of N fertilizer, followed by meteorological factors, human managements and soil characteristics. The NH3 emissions of China's cereal production (paddy rice, wheat and maize) in 2018 was estimated to be 3.3Mt NH3 -N. By 2050, NH3 volatilization will increase by 23.1-32.0% under different climate change scenarios (Representative Concentration Pathways, RCPs), and climate change will have the greatest impact on NH3 volatilization in the Yangtze river agro-region of China due to high warming effects. However, the potential increase in NH3 volatilization under future climate change can be mitigated by 26.1-47.5% through various N fertilizer management optimization options.

Assessment of climate change impacts and urban flood management schemes in central Shanghai

Increasing urbanization combined with climate change has resulted in the increased risk of flooding in cities. Thus, assessing the effect of future climate change on urban flooding and adopting effective flood management measures is becoming increasingly important. In this study, an urban rainstorm model and a scenario simulation method were applied to central Shanghai, China. We first examined the risks of flooding in the study area under the impact of future climate change using a simulation with different rainfall return periods. We then evaluated the benefits of traditional drainage system adaptation measures and Low Impact Development (LID) practices on alleviating the current urban flood hazard. Finally, we explored the effectiveness of using an integrated flood management scheme to adapt to climate change. The results show that the urban flood volume increases non-linearly with increasing rainfall intensity under climate change. The maximum flooding area also increases accordingly, and is much more sensitive to smaller rainfall events. Both traditional drainage system adaptation measures and LID practices can effectively alleviate flooding, while an integrated flood management scheme that emphasizes the combination of the two methods is shown to be the most effective in reducing flooding under future climate change.

Tools for Planning Local Mitigation of Water‐Driven Soil Erosion Resulting from Impacts of Future Climate Change

AbstractDue to the consequences of climate change impacts municipal planners and local administrations need to develop long‐term strategies to protect soil bodies. For this purpose, practicable and free available tools are developed, that allow to estimate the erosivity of rainfall and discharge, considering the effects of land use changes and climate change impacts. This paper presents a stepwise estimation of water erosivity at agricultural areas as well as streams using the developed practicable tools step model of infiltration with calculation of direct flow and soil erosion (ero‐SMINF), German universal soil loss equation integrated into a geographic information system (ABAGis), and stream erosion model (SEM). The tools are developed and tested at two catchments in mountainous areas in Central Germany, Vietzbach and Regenbeek. The results for the Vietzbach catchment, which is mostly affected by sheet erosion, indicated that most of the erosive events occur during summer. The most probable change in soil erosion resulting from climate change (RCP8.5) shows an increasing erosion of up to 16% comparing to the current state. In the Regenbeek catchment, where stream bed erosion is dominant, calculations with the SEM show for the same scenario, that erosion can be reduced mainly by widening the stream bed.

An Economy-Climate Model for Quantitatively Projecting the Impact of Future Climate Change and Its Application

Quantitatively projecting the impact of future climate change on the socio-economy and exploring its internal mechanism are of great practical significance to adapt to climate change and prevent climate risks. Based on the economy-climate (C-D-C) model, this paper introduces a yield impact of climate change (YICC) model that can quantitatively project the climate change impact. The model is based on the YICC as its core concept and uses the impact ratio of climate change (IRCC) indicator to assess the response of the economic system to climate change over a long period of time. The YICC is defined as the difference between the economic output under changing climate condition and that under assumed invariant climate condition. The IRCC not only reflects the sensitivity of economic output to climate change but also reveals the mechanism of the nonlinear interaction between climate change and non-climatic factors on the socio-economic system. Using the main grain-producing areas in China as a case study, we use the data of the ensemble average of 5 GCMs in CMIP6 to project the possible impact of climate change on grain production in the next 15–30 years under three future scenarios (SSP1-2.6, SSP2-4.5, SSP5-8.5). The results indicate that the long-term climate change in the future will have a restraining effect on production in North region and enhance production in South region. From 2021 to 2035, climate change will reduce production by 0.60–2.09% in North region, and increase production by 1.80–9.01% in South region under three future scenarios. From 2021 to 2050, compared with the climate change impact in 2021–2035, the negative impact of climate change on production in North region will weaken, and the positive impact on production in South region will enhance with the increase in emission concentration. Among them, climate change will reduce grain output in North region by 0.52–1.99%, and increase output in South region by 1.35–9.56% under the three future scenarios. The combination of economic results and climate change research is expected to provide scientific support for further revealing the economic mechanism of climate change impacts.

Global Economic Responses to Heat Stress Impacts on Worker Productivity in Crop Production

The impacts of climate change on the food system are a key concern for societies and policy makers globally. Assessments of the biophysical impacts of crop productivity show modest but uncertain impacts. But crop growth is not the only factor that matters for the food production. Climate impacts on the labour force through increased heat stress also need to be considered. Here, we provide projections for the integrated climate-induced impacts on crop yields and worker productivity on the agro-economy in a global multi-sector economic model. Biophysical impacts are derived from a multi-model ensemble, which is based on a combination of climate and crop models, and the economic analysis is conducted for different socio-economic pathways. This framework allows for a comprehensive assessment of biophysical and socio-economic risks, and outlines rapid risk increases for high-warming scenarios. Considering heat effects on labour productivity, regional production costs could increase by up to 10 percentage points or more in vulnerable tropical regions such as South and South-East Asia, and Africa. Heat stress effects on labour might offset potential benefits through productivity gains due to the carbon dioxide fertilisation effect. Agricultural adaptation through increased mechanisation might allow to alleviate some of the negative heat stress effects under optimistic scenarios of socio-economic development. Our results highlight the vulnerability of the food system to climate change impacts through multiple impact channels. Overall, we find a consistently negative impact of future climate change on crop production when accounting for worker productivity next to crop yields.

Implications of climate change for railway infrastructure

AbstractWeather phenomena can result in severe impacts on railway infrastructure. In future, projected changes to the frequency and/or intensity of extreme weather events could change weather–infrastructure risk profiles. Infrastructure owners and operators need to manage current weather impacts and put in place adequate plans to anticipate and adapt to changes in future weather risks, or mitigate the impacts arising from those risks. The assessment of the risk posed to railway infrastructure from current and future weather is dependent on a good understanding of the constituent components of risk: hazard, vulnerability, and exposure. A good understanding of the baseline and projected future risk is needed in order to understand the potential benefits of various climate change adaptation actions. Traditional risk assessment methods need some modification in order to be applied to climate change timescales, for which decisions need to be made under deep uncertainty. This review paper highlights some key challenges for assessing the risk, including: managing uncertainties; understanding weather‐impact relationships and how they could change with climate change; assessing the costs of current and future weather impacts and the potential cost versus benefit of adaptation; and understanding practices and tools for adapting railway infrastructure. The literature reveals examples of progress and good practice in all these areas, providing scope for effective knowledge‐sharing—across the railway infrastructure and other sectors—in support of infrastructure resilience and adaptation.This article is categorized under: Assessing Impacts of Climate Change &gt; Evaluating Future Impacts of Climate Change

Assessment of Future Climate Change Impact on an Agricultural Reservoir in South Korea

Drought has been frequently occurring in South Korea due to climate change. Analyzing the water supply capacity of the water resource system provides essential information for water resource management. This study evaluates the future water supply capacity of the Gwanghye (GH) agricultural reservoir based on the representative concentration pathways 4.5 and 8.5 climate change scenarios. We performed a reservoir simulation by reflecting the full water level of the reservoir before and after reservoir heightening. Climate change is expected to decrease the GH reservoir’s future available water resources due to the overall reduction in the reservoir’s runoff. After the reservoir-heightening project, an overall improvement was observed in the stability of the future irrigation water supply. Moreover, the remaining water after the supply of the irrigation water could supply 0.6–7.2 × 103 m3 of daily instream water. Thus, flexible reservoir operations are necessary according to climate change scenarios and the reservoir operation period. The use of climate change information should be expanded to establish reasonable water management policies for future climate change scenarios.

Sustainability and Existential Risks with Special Reference to Climate Change - An Overview

The initial part of this paper provides an overview on conceptual framework of sustainability and sustainable development in balancing the needs for development and environmental conservation. The concept is based on structural and functional diversity relationship of natural ecosystem functioning and environmental filters that determine its services sustainably. Subsequently, the paper deals with a brief historical perspective of eco-development initiated by the United Nations and other relevant agencies that lead to the promulgation of the “17-Sustainable Development Goals (SDGs)” in 2016. On the existential risks and potential future risks of humanity with special reference to the current and future potential impact of global climate change as consequence of energy transition from fossil fuel to renewable are also discussed. The paper ends with the way forward with an enlightenment optimism rather than romantic declinism in achieving the goal of Paris climate agreement.

Improved management may alleviate some but not all of the adverse effects of climate change on crop yields in smallholder farms in West Africa

The effect of climate change on crop yield in smallholder farms was simulated using the FAO's crop water productivity model AquaCrop and climate change projections from various climate models. This was performed for emission scenarios RCP 4.5 and 8.5 and for time horizons 2030 and 2050. Although the variation in inter-annual rainfall is projected to be substantial, the median projected change in total rainfall is predominantly slightly positive in future years. The climatic changes considered involve temperature increases of between 1.0 °C (2030) and 2.5 °C (2050), and an increase in evapotranspiration of between 3% (2030) and 7% (2050).An in-depth analysis was carried out in four pilot countries: The Gambia, Côte d'Ivoire, Mali and Niger. Four crops and two cultivation methods were considered: irrigated tomato, rainfed sorghum, and rice and maize cultivated both under irrigated and rainfed agriculture. Projections show that if management practices are not improved, climate change will have a negative impact on agricultural production. On average, yield is expected to decline by 5 to 20%, depending on the crop, agro-ecological zone and time horizon. Simulations indicate that the cultivation of sorghum in the Sahelian zone may no longer be feasible under future climatic conditions.If management practices are not improved, the yield gap increases with climate change. To benefit from CO2 fertilization in future years, future soil fertility needs to increase by at least 15 to 20% in order to maintain current levels. Improved fertility management could lead to an increase in crop yields of between 5 and 14% for irrigated tomato and irrigated and rainfed rice. The impact of future climate changes on maize yield, maize being a C4 crop which benefits less from CO2 fertilization, was mostly negative even with improved soil fertility management.

A meta-analysis of the possible impact of climate change on global cotton yield based on crop simulation approaches

CONTEXT:Cotton is one of the most widely planted fiber crops in the world. Its growth, development, and yield are influenced by elevated atmospheric CO2 concentrations, temperature increases, and seasonal rainfall patterns. However, due to differences in research methods (such as crop models, climate models, and climate scenarios), there are uncertainties in the magnitude and direction of the impact of future climate change on cotton yields in existing studies. OBJECTIVETo comprehensively assess the potential impact of climate change and adaptation on yieldand analyze the associated uncertainties, 27 published studies (including 1353 samples) were used to establish a meta database of changes in future cotton yield. METHODSThe responses of cotton relative yield change to changes in mean temperature, minimum temperature, maximum temperature, precipitation, and CO2 concentration were studied using local polynomial (Loess) regression in a full dataset. A linear mixed-effect model was then used to explore the quantitative relationship between them in a restricted dataset. RESULTS AND CONCLUSIONSUsing the established full dataset, we found that when the average temperature exceeded 4.3 °C, or the average precipitation decreased or increased too much (>200%), the simulated cotton yield decreased. Elevated CO2 concentrations and appropriate management measures could alleviate the negative impact of climate change. By establishing a linear mixed-effect model, we found that temperature, precipitation, CO2 concentration changes, adaptive measures, study area, climate models, and climate scenarios had significant impacts on cotton yield change. For every 1 °C increase in average temperature, the cotton yield decreased by 1.64%. For every 1% increase in precipitation and 1 ppm increase in CO2 concentration, cotton yield increased by 0.09% and 0.05%, respectively. Cotton yield under adaptation measures was 8.97% higher than without any adaptation. SIGNIFICANCEThe first systematic meta-analysis of the impact of climate change on cotton yield in major cotton-planting regionswas conducted herein. The findings provide new information for policies related to the impact of climate change and enhance our understanding of the future resilience of the cotton system.

Improvement of the Outdoor Thermal Comfort by Water Spraying in a High-Density Urban Environment under the Influence of a Future (2050) Climate

Adaptation to prepare for adverse climate change impacts in the context of urban heat islands and outdoor thermal comfort (OTC) is receiving growing concern. However, knowledge of quantitative microclimatic conditions within the urban boundary layer in the future is still lacking, such that the introduction of adequate adaptation measures to increase OTC is challenging. To investigate the cooling performance of a water spraying system in a sub-tropical compact and high-rise built environment in summer under the influence of future (2050) climatic conditions, results from two validated models (Weather Research and Forecast (WRF) and ENVI-met models) have been used and analyzed. Our results indicate that the spraying system provides cooling of 2–3 °C for ambient air temperature at the pedestrian-level of the urban canyons considered here, which benefits pedestrians. However, improvement of the OTC in terms of the physiological equivalent temperature (PET—a better indicator of human thermal sensation) was noticeable (e.g., &lt;42 °C or from very hot to hot) when the urban canyon was orientated parallel to the prevailing wind direction only. This implies that in order to improve city resilience in terms of heat stress, more holistic adaptation measures in urban planning are needed. This includes the introduction of more breezeways and building disposition to facilitate the urban ventilation, as well as urban tree arrangement and sunshades to reduce direct solar radiation to plan for the impact of future climate change.

Future Climate Change Impact on Urban Heat Island in Two Mediterranean Cities Based on High-Resolution Regional Climate Simulations

The Mediterranean is recognized among the most responsive regions to climate change, with annual temperatures projected to increase by 1–5 °C until 2100. Large cities may experience an additional stress discomfort due to the Urban Heat Island (UHI) effect. In the present study, the WRF-ARW numerical weather prediction model was used to investigate the climate change impact on UHI for two Mediterranean cities, Rome and Thessaloniki. For this purpose, three 5-year time-slice simulations were conducted (2006–2010, 2046–2050, 2096–2100) under the Representative Concentration Pathway (RCP) 8.5 emission scenario, with a spatial resolution of 2 km. In order to comprehensively investigate the urban microclimate, we analyze future simulation data across sections crossing urban/non-urban areas, and after grouping them into three classes depending on the location of the grid cells. The urban areas of both cities present increased average minimum temperature (Tmin) in winter/summer compared to other rural areas, with an UHI of ~+1.5–3 °C on average at night/early morning. Considering UHI under future climate change, we found no significant variations (~±0.2 °C). Finally, we found that the numbers of days with Tmin ≥ 20 °C will mostly increase in urban coastal areas until 2100, while the largest increase of minimum Discomfort Index (DImin) is expected in urban low-ground areas.