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Global warming is one of the most pressing challenges of our time, contributing to climate change effects and with far-reaching implications for built environments. The main aim of this study is to assess the extent to which Annaba city, Algeria, as part of the Mediterranean region, is affected by global climate change and its broader influences. The study investigated climatic shifts in Annaba city, using a multi-step methodology integrating data collection and analysis techniques. Data collection included 23 years of climate data (2000–2023) from Annaba's meteorological station, on-site measurements of microclimatic variations, and a questionnaire survey. The collected data underwent four main analyses: a time series analysis to describe climate parameters over 23 years, a statistical analysis to predict potential future climatic conditions (2024–2029) and the correlation of various climatic variables using specialized bioclimate tools to highlight seasonal variability, a spatial study of the urban heat island (UHI) phenomenon and perceived climatic shifts, and an analysis of extreme weather events characterizing heat atmospheric events in the context of urban climate change in the Mediterranean region. The findings revealed a consistent warming trend in Annaba city, with prolonged extreme climate conditions observed, particularly in the last four years (2020–2023). Significant temperature fluctuations were emphasized, notably in July 2023, with record-breaking maximum temperatures reaching 48.2 °C, the hottest on record with an increase of 3.8 °C, and presenting challenges amplified by the urban heat island effect, causing temperature differentials of up to 6 °C within built-up areas. Projections for 2029 suggest a tendency towards heightened aridity with a significant shift towards a new climate seasonality featuring two distinct main seasons—moderate and hot challenging. The abrupt disruption of calm weather conditions in Annaba on 24 July 2023 highlighted the influence of atmospheric circulation within the Mediterranean region featured for both anticyclones and atmospheric blocking phenomena on local weather patterns. [ABSTRACT FROM AUTHOR]

AbstractIn Egypt, El-Mansourah Conurbation (EMC) is the second largest urban complex after Cairo Conurbation. This study focuses on identifying seasonal trends in land surface temperature during the daytime/nighttime in both urban and rural areas (RA), as well as the corresponding urban heat island (UHI) intensity 2001 to 2021. A time series of the Moderate Resolution Imaging Spectroradiometer (Terra MODIS) images was analyzed using the statistical methods of Mann-Kendall test (MKT) and Theil-Sen estimator (TSE). The findings showed that the diurnal cooling in ranged from −0.66 to −0.58 °C (p .1). Calculations of the Temperature-Humidity Index showed a decline in the population comfort over time, especially in the hot months, while there was a noticeable amelioration in the cool ones. To explore potential mitigation strategies, the simulation capabilities of ENVI-met were utilized. Based on a simple scenario, the ambient temperature of Salah Salem Street (SST) decreased by more than 2 °C. One suggestion put forth by the research is to implement mitigation measures to address the adverse consequences that naturally arise from the unavoidable dynamics of urban areas.

A comprehensive comparison of the trends and drivers of global surface and canopy urban heat islands (termed Is and Ic trends, respectively) is critical for better designing urban heat mitigation strategies. However, such a global comparison remains largely absent. Using spatially continuous land surface temperatures and surface air temperatures (2003–2020), here we find that the magnitude of the global mean Is trend (0.19 ± 0.006°C/decade, mean ± SE) for 5,643 cities worldwide is nearly six‐times the corresponding Ic trend (0.03 ± 0.002°C/decade) during the day, while the former (0.06 ± 0.004°C/decade) is double the latter (0.03 ± 0.002°C/decade) at night. Variable importance scores indicate that global daytime Is trend is slightly more controlled by surface property, while background climate plays a more dominant role in regulating global daytime Ic trend. At night, both global Is and Ic trends are mainly controlled by background climate. Plain Language Summary: Surface and canopy urban heat islands (surface and canopy UHIs, termed Is and Ic) are two major UHI types. These two counterparts are both related to urban population heat exposure and have long been a focus of urban climate research. However, the differences in the trends and major determinants of Is and Ic over global cities remain largely unclear. Based on spatially continuous land surface temperature and surface air temperature observations from 2003 to 2020, we find that the global mean Is trends are about 6.3 times and 2 times the Ic trends during the day and at night, respectively. During the day, the global Is trend is more regulated by surface property than by background climate, and vice versa for global Ic trend. At night, both the global Is and Ic trends are mainly regulated by background climate. These findings are important for better understanding global urban climate change and informing heat mitigation strategies. Key Points: The global Is trend is six‐fold and twofold larger than the Ic trend during the day and at night, respectivelyDuring the day, global Is trend is slightly more controlled by surface property, yet background climate plays a dominant role in Ic trendAt night, both global Is and Ic trends are more regulated by background climate [ABSTRACT FROM AUTHOR]

Global warming is one of the most pressing challenges of our time, contributing to climate change effects and with far-reaching implications for built environments. The main aim of this study is to assess the extent to which Annaba city, Algeria, as part of the Mediterranean region, is affected by global climate change and its broader influences. The study investigated climatic shifts in Annaba city, using a multi-step methodology integrating data collection and analysis techniques. Data collection included 23 years of climate data (2000–2023) from Annaba’s meteorological station, on-site measurements of microclimatic variations, and a questionnaire survey. The collected data underwent four main analyses: a time series analysis to describe climate parameters over 23 years, a statistical analysis to predict potential future climatic conditions (2024–2029) and the correlation of various climatic variables using specialized bioclimate tools to highlight seasonal variability, a spatial study of the urban heat island (UHI) phenomenon and perceived climatic shifts, and an analysis of extreme weather events characterizing heat atmospheric events in the context of urban climate change in the Mediterranean region. The findings revealed a consistent warming trend in Annaba city, with prolonged extreme climate conditions observed, particularly in the last four years (2020–2023). Significant temperature fluctuations were emphasized, notably in July 2023, with record-breaking maximum temperatures reaching 48.2 °C, the hottest on record with an increase of 3.8 °C, and presenting challenges amplified by the urban heat island effect, causing temperature differentials of up to 6 °C within built-up areas. Projections for 2029 suggest a tendency towards heightened aridity with a significant shift towards a new climate seasonality featuring two distinct main seasons—moderate and hot challenging. The abrupt disruption of calm weather conditions in Annaba on 24 July 2023 highlighted the influence of atmospheric circulation within the Mediterranean region featured for both anticyclones and atmospheric blocking phenomena on local weather patterns.

Abstract A comprehensive comparison of the trends and drivers of global surface and canopy urban heat islands (termed Is and Ic trends, respectively) is critical for better designing urban heat mitigation strategies. However, such a global comparison remains largely absent. Using spatially continuous land surface temperatures and surface air temperatures (2003–2020), here we find that the magnitude of the global mean Is trend (0.19 ± 0.006°C/decade, mean ± SE) for 5,643 cities worldwide is nearly six‐times the corresponding Ic trend (0.03 ± 0.002°C/decade) during the day, while the former (0.06 ± 0.004°C/decade) is double the latter (0.03 ± 0.002°C/decade) at night. Variable importance scores indicate that global daytime Is trend is slightly more controlled by surface property, while background climate plays a more dominant role in regulating global daytime Ic trend. At night, both global Is and Ic trends are mainly controlled by background climate.

Climate change and rapid urbanization are two global processes that have significantly aggravated natural disasters, such as drought and flooding. Urbanization without resilient and sustainable planning and execution could lead to undesirable changes in landscapes and stormwater regulation capacity. These changes have exacerbated the effects of extreme climatic events with disastrous consequences in many cities worldwide. Unfortunately, the major storm in Zhengzhou, China on 20 July 2021 was one of these examples. This event provided a rare opportunity to study the key roles of green infrastructures (GI) in mitigating flooding risks in a major urban center after a devasting flood event. Using the data from high-resolution images collected via two satellites, a comprehensive study of the Jialu System in Greater Zhengzhou was conducted to systematically compare how far the river water had reached before and after the 20 July 2021 major storm in order to identify the main weak links in the city's GI and stormwater management system. A flood inundation intensity index (FI) in the Upper (UJLR), Middle (MJLR), and Lower (LJLR) Regions of the Jialu River System was generated. Bivariate Moran's I, a correlation coefficient between FI and landscape characteristics, was calculated and used to identify problem areas for future improvements. Our results showed that the MJLR had the severest flooding impacts. LJLR had the biggest change in how far the river water reached after flooding, ranging from 4.59 m to 706.28 m. In UJLR, the percentages of mine, crop land, and green space had the highest global bivariate Moran's I correlation coefficients. In MJLR, the percentages of vacant land, impervious surfaces, and water body had the highest global bivariate Moran's I correlation coefficients. In LJLR, the percentages of vacant land, water body, and crop land had the highest global bivariate Moran's I correlation coefficients. The total percentages of both high landscape characteristics indices-high flood inundation intensity indices and low landscape characteristics indices-high flood inundation intensity indices areas are 12.96%, 13.47%, and 13.80% in UJLR, MJLR, and LJLR, respectively. These land cover composition types identified for each region can be treated as areas of primary focus. However, GeoDector Model (GDM) analyses showed that our eight variables of landscape characteristics were not independent. Hence, a more comprehensive approach integrating all eight variables is still necessary in future flood mitigation efforts. [ABSTRACT FROM AUTHOR]

Climate change is one of the great global challenges. Cities are both drivers and responders of climate change. In recent years, the literature associated with climate change and cities has grown rapidly, but few studies have used a bibliometric analysis and visualization approach to conduct deep mining and explore the current situation and development trends of this field. By using bibliometric and text mining methods, the authors conducted a knowledge map analysis of the research on cities and climate change. Moreover, this article attempts to identify the research hotspots and research gaps in this field. The following findings are distilled. First, research in this field is rapidly emerging, and the current research distribution is extremely uneven. China and the US contributed 36% of total paper output. Second, previous research focused on six topics: Impact of Climate Change and Urbanization, Urban Climate Change Adaptation, Urban Heat Island Effect, Urban Greenhouse Emission, Urban Climate Change and Water, and Urban Energy Systems. The first two topics are currently the most popular directions of research. Third, empirical research shows positive interest in big cities, while climate change research in small and medium-sized cities has been neglected. The results of this work will not only help researchers clarify the current situation in cities and climate change science but also provide guidance for future research. [ABSTRACT FROM AUTHOR]

In urban heat island (UHI) effect modeling, traditional 3D morphological indexes often homogenize elements within units, leading to a loss of spatial detail. Here we introduce detailed stereoscopic urban morphology indices, including the Height Variation Coefficient, the Height Gravity Index, the Mixed Degree, and the Aggregation Degree, using urban building and vegetation height data to represent the 3D structures within urban units. We employed ensemble learning algorithms to explore nonlinear effects and statistical correlations across 20 buffer radii (100 m to 2000 m) related to the UHI effect. The integration of these inhomogeneous indexes substantially improved model accuracy, with XGBoost achieving an R2 of 0.95. The optimal scale for calculating such indexes was found to be between 300 m and 400 m. Our findings suggest optimizing UHI mitigation by lowering the Building Height Coefficient in high-density areas and increasing it in low-density regions. Furthermore, we propose tailoring the Vegetation Height Coefficient for green spaces, advocating higher values for larger parks and lower values for smaller ones. This approach offers practical insights for mitigating urban heat effects through customized morphological strategies, emphasizing the importance of precise urban planning and environmental management. • Stereoscopic Urban Morphology Indexes enhance LST prediction accuracy. • We recommend lower BHC in high-density areas, raise it in low-density areas. • Forest parks require higher VHC, while pocket parks demand lower VHC • The optimal scale for examining the 3D urban structure-UHI link is 300-400 m [ABSTRACT FROM AUTHOR]

Climate change and its urban dimensions have become more actively debated topics since the beginning of the millennium. As a result of being such a recent concern, the available definitions of what is at stake and what is needed to deal with it—in particular who should deal with it—are often too broad, vague and even disputable depending on the interlocutors, and often focussed on the rural areas. In the context of urban climate change in Luanda and in Maputo, there is an undefined set of tasks and responsibilities to deal with the impacts and prevent further negative effects to the urban dwellers and the poor in particular. This article identifies recurrently mentioned areas where the state is considered absent (and should be present). Based on fieldwork conducted in Luanda and in Maputo, the available literature, accounts of expert stakeholders, and the appraisals and claims of the urban dwellers, this article analyses the existing legal and policy dispositions and the existing systems and resources to deal with climate change. This is simultaneously confronted with what policy stakeholders, urban practitioners and urban dwellers on the ground see that is missing, needs to be improved, and is urgent and capable of improving daily lives. The main findings are that responsibilities and attributions, despite being unclear and not fully defined, predominantly rely on the state and state institutions. [ABSTRACT FROM AUTHOR]

Climate change and rapid urbanization are two global processes that have significantly aggravated natural disasters, such as drought and flooding. Urbanization without resilient and sustainable planning and execution could lead to undesirable changes in landscapes and stormwater regulation capacity. These changes have exacerbated the effects of extreme climatic events with disastrous consequences in many cities worldwide. Unfortunately, the major storm in Zhengzhou, China on 20 July 2021 was one of these examples. This event provided a rare opportunity to study the key roles of green infrastructures (GI) in mitigating flooding risks in a major urban center after a devasting flood event. Using the data from high-resolution images collected via two satellites, a comprehensive study of the Jialu System in Greater Zhengzhou was conducted to systematically compare how far the river water had reached before and after the 20 July 2021 major storm in order to identify the main weak links in the city’s GI and stormwater management system. A flood inundation intensity index (FI) in the Upper (UJLR), Middle (MJLR), and Lower (LJLR) Regions of the Jialu River System was generated. Bivariate Moran’s I, a correlation coefficient between FI and landscape characteristics, was calculated and used to identify problem areas for future improvements. Our results showed that the MJLR had the severest flooding impacts. LJLR had the biggest change in how far the river water reached after flooding, ranging from 4.59 m to 706.28 m. In UJLR, the percentages of mine, crop land, and green space had the highest global bivariate Moran’s I correlation coefficients. In MJLR, the percentages of vacant land, impervious surfaces, and water body had the highest global bivariate Moran’s I correlation coefficients. In LJLR, the percentages of vacant land, water body, and crop land had the highest global bivariate Moran’s I correlation coefficients. The total percentages of both high landscape characteristics indices-high flood inundation intensity indices and low landscape characteristics indices-high flood inundation intensity indices areas are 12.96%, 13.47%, and 13.80% in UJLR, MJLR, and LJLR, respectively. These land cover composition types identified for each region can be treated as areas of primary focus. However, GeoDector Model (GDM) analyses showed that our eight variables of landscape characteristics were not independent. Hence, a more comprehensive approach integrating all eight variables is still necessary in future flood mitigation efforts.

Urbanized areas modify the local climate due to the physical properties and morphology of surface objects. The urban impacts on local scale interact with the regional climate resulting in an amplification of certain climate aspects in the cities (e.g., higher maximum air temperature), which may be further enhanced with climate change. Regional climate models provide adequate tool for assessing the regional characteristics of global changes, however, they are incapable for describing the local impacts, e.g., in cities, due to their relatively low resolution (usually 10-25 km horizontally) and due to the lack of detailed description of relevant physical processes. To investigate the future climate change in cities, surface models provide a scientifically sound and cutting-edge solution for the previous problem. In this study, the behavior of SURFEX externalized land surface model including the TEB urban canopy scheme and coupled to the ALADIN-Climate regional climate model in offline mode is investigated. A 10-year-long simulation for 2001-2010 was achieved on 1 km resolution for Budapest. The main goals of our investigation are i) to assess how the biases of the regional climate model inherited and modified by SURFEX, ii) what is the added value of SURFEX to ALADIN-Climate, and iii) what are the capabilities of SURFEX in terms of describing urban and suburban seasonal temperature cycle and daily urban heat island (UHI) evolution in Budapest. Quantified validation is conducted using the measurements of two stations located in the city center and in the suburban area. It was found that SURFEX overestimates the 2 m temperature in both locations throughout the year, in spite of the too cold ALADIN forcings. The strength of nocturnal UHI is overestimated from autumn till spring, while it is slightly too weak in summer. Moreover, the evolution and collapse of daily UHI is imperfectly simulated, namely some delay and slower daily dynamics occur, which might be caused by the method applied for deriving the atmospheric forcings. [ABSTRACT FROM AUTHOR]

Urban climate results from the modifications caused by the characteristics of cities, which modifies the regional climatic conditions of a city. When urban areas are warmer than the surrounding areas, the urban heat island (UHI) phenomenon occurs. Being a major phenomenon and a global topic of interest for all affected cities, there are already numerous studies that address this subject. However, most studies are only focused on the macro and mesoscales. This study looks at the micrometeorological scale in a neighborhood of Lisbon (Telheiras). Having as a main objective to evaluate how the radiation balance of urban materials influences air temperature in an urban canyon, thermal images of different urban materials were obtained using infrared thermography, a technique that allowed understanding how the temperatures registered in the facades and other urban surfaces can affect the air temperature of the urban canyon. The components of the radiation budget were obtained by using a pyranometer and a pyrgeometer. Moreover, a microclimatic network to monitor air temperature and relative humidity was installed in the study area. The results show that, when the streets are less exposed to the prevailing wind direction in Lisbon (north and northwest), air temperatures are slightly higher than those found in opposite conditions. Both the temperature and the radiative balance of the facades and other surfaces (asphalt, light Portuguese sidewalk, and tile floor) respond directly to incident solar radiation. As expected, it was found that south facades have the highest temperatures of the four exposures under study (>4 °C when compared to the opposite facade), and the highest radiative balance was always registered on asphalt when compared to the sidewalk (at 9:00 a.m. + 30 W∙m−2, at 1:00 p.m. + 149 W∙m−2, and at 7:00 p.m. + 66 W∙m−2). [ABSTRACT FROM AUTHOR]

Risk analysis of urban flood and drought can provide useful guidance for urban rainwater management. Based on an analysis of urban climate characteristics in 2,264 Chinese cities from 1958 to 2017, this study evaluated urban flood and drought risks. The results demonstrated that the annual average values of precipitation, aridity index, frequency and intensity of extreme precipitation and extreme drought events differed significantly in these cities. The values of the above six climatic indicators in the cities ranged from 9.29–2639.30 mm, 0.47–54.73, 1.08–8.79 time, 7.82–107.25 mm, 0.76–2.99 time, and 10.30–131.19 days, respectively. The geographical patterns of urban precipitation, aridity index, intensity and frequency of extreme precipitation and drought events in China fit well to the Hu‐Huanyong Line that was created in 1940s to identify the pattern of population distribution. Extreme precipitation in most cities has upward trends, except for those around the Hu‐Huanyong Line. The extreme drought events had upward trends in the cities east of the Hu‐Huanyong Line, but there were downward trends in the cities west of the line. The risk assessment indicated that 3.80% cities were facing serious flood and 6.01% cities were facing serious drought risks, which are located in the coast of southern China and northwestern China, respectively, and other 90.19% cities were facing different types of drought and flood risks in terms of their intensity and frequency. [ABSTRACT FROM AUTHOR]

Abstract Sealed surfaces greatly influence Urban Heat Island (UHI) effects. In this respect, both the composition and spatial patterns of anthropogenic land use play an important role in local thermal pattern. The urban environments' climate change adaptation strategy needs adequate knowledge systems urban planners can use to organise and design more resistant and resilient urban spaces. This study examined the relationship between Land Surface Temperature (LST) variations and increasing urbanised areas during the period 2001–2011 in the Po Valley, utilising different urban growth spatial patterns (UGSP). Remotely sensed LST data was obtained from MODIS (MODerate Resolution Imaging Spectroradiometer) at a resolution of 1 km/pixel for an 11 year-period, from 2001 to 2011, with urbanisation data from the ISTAT map (nominal scale 1:10,000) respectively for the 2001 and 2011 time sections. The relationship between dependent (mean annual daytime, nighttime and daily values) and independent (urbanised areas) variables were investigated through ANOVA test and post-hoc analysis (p < 0.01) for all defined UGSP. Results showed that there is a decreasing LST range (in all conditions) associated with progressive increase of urbanised areas. Furthermore, clustered patterns urban growth have a statistically significant relationship with daytime, nighttime and daily conditions while dispersed pattern urban growth have the same with nighttime only. The outcomes are helpful for understanding the effects of different UGSP, which have significant implications for urban planning, and identifying the critical territorial sectors in need of sustainable mitigation actions. Graphical abstract Unlabelled Image Highlights • Between 2001 and 2011, the Po Valley area saw an increase of 630 km2 in urban areas. • The prevailing model of urban growth is the UDI 0 (aggregated urban growth). • The LST in daytime conditions was an average increase of +1,36 °C in the study area. • Quantitative framework between increased urbanised areas and LST change performed. • The UDI + (urban dispersion) shows an increase in the minimum differential recorded. [ABSTRACT FROM AUTHOR]

Urban climate results from the modifications caused by the characteristics of cities, which modifies the regional climatic conditions of a city. When urban areas are warmer than the surrounding areas, the urban heat island (UHI) phenomenon occurs. Being a major phenomenon and a global topic of interest for all affected cities, there are already numerous studies that address this subject. However, most studies are only focused on the macro and mesoscales. This study looks at the micrometeorological scale in a neighborhood of Lisbon (Telheiras). Having as a main objective to evaluate how the radiation balance of urban materials influences air temperature in an urban canyon, thermal images of different urban materials were obtained using infrared thermography, a technique that allowed understanding how the temperatures registered in the facades and other urban surfaces can affect the air temperature of the urban canyon. The components of the radiation budget were obtained by using a pyranometer and a pyrgeometer. Moreover, a microclimatic network to monitor air temperature and relative humidity was installed in the study area. The results show that, when the streets are less exposed to the prevailing wind direction in Lisbon (north and northwest), air temperatures are slightly higher than those found in opposite conditions. Both the temperature and the radiative balance of the facades and other surfaces (asphalt, light Portuguese sidewalk, and tile floor) respond directly to incident solar radiation. As expected, it was found that south facades have the highest temperatures of the four exposures under study (>4 °C when compared to the opposite facade), and the highest radiative balance was always registered on asphalt when compared to the sidewalk (at 9:00 a.m. + 30 W∙m−2, at 1:00 p.m. + 149 W∙m−2, and at 7:00 p.m. + 66 W∙m−2).

Climate change will impact urban areas. Decision makers need useful climate information to adapt adequately. This research aims to improve understanding of changes in moisture and temperature projected under climate change in Berlin compared to its surroundings. Simulations for the Representative Concentration Pathway (RCP) 8.5 scenario from the European Coordinated Regional Climate Downscaling Experiment (EURO-CORDEX) 0.11° are analyzed, showing a difference in moisture and temperature variables between Berlin and its surroundings. The running mean over 30 years shows a divergence throughout the twenty-first century for relative humidity between Berlin and its surroundings. Under this scenario, Berlin gets drier over time. The Mann-Kendall test quantifies a robust decreasing trend in relative humidity for the multi-model ensemble throughout the twenty-first century. The Mann-Whitney-Wilcoxon test for relative humidity indicates a robust climate change signal in Berlin. It is drier and warmer in Berlin compared to its surroundings for all months with the largest difference existing in summer. Additionally, the change in humidity for the period 2070−2099 compared to 1971−2000 is larger in the summer months. This study presents results to better understand near surface moisture change and related variables under long-term climate change in urban areas compared to their rural surroundings using a regional climate multi-model ensemble.

Climate change impacts are intensifying social inequalities locally and globally. Exposure to climate risks, as well as the ability to prepare for and recover from them, are affected by complex power structures. An expanding body of literature uses an intersectional lens to explicate a more nuanced understanding of how co-constituted power structures manufacture differential climate vulnerabilities. Despite the increasing focus on intersectional approaches to institutionalized climate planning, there are limited quantitative studies examining how the co-constituted processes of being racialized and gendered influence climate change perceptions in the United States. In contribution to these conversations, we examine how race and gender together shape experiences of climate impacts, perceptions of future risk, and desires for adaptation actors in Austin, Texas. Using a survey of Austin area households, we explored climate perceptions including residents self-reported experience of four types of climate events, assessment of changing climate risks, overall climate change concerns, and desires for resilience actions by a variety of actors. Our research suggests that race and gender, income levels, and political party are related to which climate events people report experiencing, their perception of changes to various climate risks, their overall climate concern, and their support for various climate adaptation actors. • Urban climate plans often overlook how race and gender influence climate perceptions. • We examine how race and gender shape climate impacts, concern, and desired actors. • Race, gender, politics, income, and education affect climate perceptions in Austin, TX. • Black women reported the fewest climate impacts but the highest climate concern. • Over 85% of residents support local government climate adaptation actions. [ABSTRACT FROM AUTHOR]

Under consideration of climate change, high-resolution (100 m × 100 m) assessments of heat events were performed for Augsburg, Southern Germany, for the extended summer season (May–September). Heat (anomaly) days were defined as days exceeding absolute (relative) temperature thresholds. The focus is on the assessment of how the number and duration of events change under future climate conditions and how e.g., green spaces or sealed areas affect the intra-urban structure of heat (anomaly) events. Assessments were performed under consideration of two Representative Concentration Pathways (RCP4.5 and RCP8.5). The method is based on a two-step statistical approach: a novel analog technique (Normal VECtor of circulation patterns, NVEC) to downscale large-scale information on point observation and a spatial model (Multiple Linear Regression, MLR) for estimating temperature patterns across the entire urban area. The model calibration and validation were performed by an urban meteorological network of 38 monitoring stations for air temperature. Results show that differences between RCP4.5 and RCP8.5 are only small until 2040. At the end of the 21st century, the number of heat days for RCP8.5 is four times higher than under consideration of RCP4.5 and 33 times higher than within the reference period (1970–2000) leading to more and longer lasting events. • A two-step statistical downscaling approach was used to estimate temperatures for the city of Augsburg • Assessments of temperatures and heat events for the 21st century were made at a high spatial resolution (100 m × 100 m) • Significant differences between RCP4.5 and RCP8.5 first occur around the mid-21st century • The cooler regions of the city in particular are feeling the consequences of higher greenhouse gas emissions • By the end of the 21st century, the duration of the heat day period increases significantly, especially under RCP8.5 [ABSTRACT FROM AUTHOR]

The effects of climate change (CC) have intensified in Ghana, especially in the Greater Accra region over the last two decades. CC assessment under the new IPCC scenarios and consistent local station data is limited. Consequently, CC assessment is becoming difficult in data-scarce regions in Ghana. This study utilizes six different Regional Climate Models under the 6th IPCC Report's Shared Socioeconomic Pathway scenarios (SSPs) of the CMIP6, which were bias-corrected with CMhyd over Greater Accra using ground station and PUGMF reanalysis data. The study reveals a reduction and potential shift in the intensity of precipitation in the region under the SSPs. Maximum temperature is expected to increase by 0.81–1.45 °C, 0.84–1.54 °C, 0.96–1.70 °C and 0.98–1.73 °C, while minimum temperature would likely increase by 1.33–2.02 °C, 1.49–2.22 °C, 1.71–4.75 °C and 1.75–4.83 °C under SSP1–2.6, SSP2–4.5, SSP3–7.0, and SSP5–8.5 scenarios, respectively. Thus, temperature will likely increase, especially at night in the near future. Rising temperatures and changes in precipitation have impacts on all strata of society, from agricultural production to power generation and beyond. These findings can help inform Ghanaian policymaking on Sustainable Development Goals 11 and 13 as well as nationally determined contributions within the Paris Agreement. • The study utilizes six different Regional Climate Models to assess the Shared Socioeconomic Pathway scenarios (SSPs) of the CMIP6, over Greater Accra • The study reveals that Greater Accra is projected to be vulnerable to climate change in the future • The study reveals a reduction and potential shift in the intensity of precipitation in the region under the SSPs • Temperature will likely increase, especially at night in the near future. • These findings can help inform Ghanaian policymaking on Sustainable Development Goals 11 and 13 [ABSTRACT FROM AUTHOR]

Increased awareness of the urban heat island (UHI) effect has drawn attention to monitoring and evaluating outdoor thermal comfort in cities worldwide. Especially in China, rapid, large-scale urban development is producing urban climate change in large cities, creating other urban environmental problems such as haze weather. Currently, studies are being conducted in China to reveal the impact of urban development on urban climate change. Few studies, however, have focused on microscale urban planning styles and urban typology. High-density building development will change the urban typology, leading to changes in the urban sky view factor (SVF) and microclimate. Our previous study explored the relationship between SVF and the UHI effect by assessing the effect of SVF on the urban thermal environment. Since the energy consumed by indoor heating and air conditioning is affected by mean air temperature (Ta), a high SVF should be considered in the urban planning stage. In this study, we analyzed typical urban planning styles in China. We selected microscale residential districts in Xi’an to represent the typical urban typology of residential districts that developed during different periods and used the numerical urban simulation system ENVI-met to evaluate the impact of urban typology change on urban climate change. Using this approach, we determined the effects of building density, building styles, and vegetation system design, thus demonstrating the mechanism of urban climate change in China's larger cities. This analysis of planning styles can provide guidance for future environmental urban development. [ABSTRACT FROM AUTHOR]

This study analyzes the influence of urban-geographical variables on determining heat islands and proposes a model to estimate and spatialize the maximum intensity of urban heat islands (UHI). Simulations of the UHI based on the increase of normalized difference vegetation index (NDVI), using multiple linear regression, in Iporá (Brazil) are also presented. The results showed that the UHI intensity of this small city tended to be lower than that of bigger cities. Urban geometry and vegetation (UI and NDVI) were the variables that contributed the most to explain the variability of the maximum UHI intensity. It was observed that areas located in valleys had lower thermal values, suggesting a cool island effect. With the increase in NDVI in the central area of a maximum UHI, there was a significant decrease in its intensity and size (a 45% area reduction). It is noteworthy that it was possible to spatialize the UHI to the whole urban area by using multiple linear regression, providing an analysis of the urban set from urban-geographical variables and thus performing prognostic simulations that can be adapted to other small tropical cities. [ABSTRACT FROM AUTHOR]

A distinct feature of Wuhan is that almost a quarter of the total area of this city is covered with water, leading to its unique hot and humid climate characteristics in summer. However, according to records, water area in built-up zone of Wuhan has been reduced by 130.5 km2 from 1965 to 2008, while the annual average air temperature has been increased by more than 3℃. To investigate the quantitative connection between the water area reduction and air temperature increase, three scenarios were simulated in a summer; to evaluate the impact of water reduction on the local thermal environment in different water areas; and to study the impact of water reduction on the urban heat island (UHI) phenomenon. Meso-scale meteorological models of Weather Research and Forecasting model were applied in this study for quantitative assessment and prediction. With the predictions, this study reveals that the decreased water area could affect air temperature, wind velocity and wind flow direction, energy balance and the UHI intensity. The simulations show that areas with significant wind velocity, wind direction and air temperature differences are distributed among the downwind zones. Moreover, the areas with high UHI intensity are wider and farther from the boundary of urban areas because of the reduction of water areas. [ABSTRACT FROM AUTHOR]

This study analyzes the influence of urban-geographical variables on determining heat islands and proposes a model to estimate and spatialize the maximum intensity of urban heat islands (UHI). Simulations of the UHI based on the increase of normalized difference vegetation index (NDVI), using multiple linear regression, in Iporá (Brazil) are also presented. The results showed that the UHI intensity of this small city tended to be lower than that of bigger cities. Urban geometry and vegetation (UI and NDVI) were the variables that contributed the most to explain the variability of the maximum UHI intensity. It was observed that areas located in valleys had lower thermal values, suggesting a cool island effect. With the increase in NDVI in the central area of a maximum UHI, there was a significant decrease in its intensity and size (a 45% area reduction). It is noteworthy that it was possible to spatialize the UHI to the whole urban area by using multiple linear regression, providing an analysis of the urban set from urban-geographical variables and thus performing prognostic simulations that can be adapted to other small tropical cities.

Recent studies on fine-scale spatial variations of urban air temperature revealed that urban environments are urban heat "archipelagos", rather than "islands," and there are locations with higher temperatures which suffer more intensive urban heat, and people in these areas are likely to experience greater heat stress and health risks. However, study of this phenomenon is limited because of insufficient air temperature data at the fine scale. This study attempted to quantify the heterogeneity of air and land surface temperature (LST), and their relationship in a fine-scale urban environment using field-measured air temperature and Landsat 8-based LST data. We found: (1) there was a strong thermal heterogeneity at the fine scale even between the measurement points on the edges of a large urban park. The maximum temperature difference reached 4.2 °C for air temperature and 8 °C for LST in the study area. (2) Air and surface temperatures were positively correlated. However, their cool and hot spots did not always overlap in space. (3) air temperature is more complex than LST, and more parameters in the urban environment can influence air temperature. (4) Urban landscape and climatological parameters can enhance the applicability of LST as a proxy for air temperature from 39% to 57%. The results have theoretical and practical implications for identifying the locations on a fine scale with extreme heat and attracting the attention of urban planners to take adoption measures. • Fine-scale air temperature variations were considered based on field-measurement data. • There is a strong thermal heterogeneity in fine-scale intra-urban areas. • LST might be applicable as a proxy to study air temperature variations. • Considering landscape and climatological parameters enhances such applicability. [ABSTRACT FROM AUTHOR]

Abstract: The paper aims at predicting the co-benefits of implementing the greenhouse gas mitigation measures. We carry out a time series driver assessment in Shenyang city, one of the most famous heavy industrial cities in China by employing STIRPAT (Stochastic Impacts by Regression on Population, Affluence and Technology) model. Population growth has been one driver on emissions growth over the past decades, while urbanization can also significantly affect carbon emissions. In addition, the per capita GDP and carbon emissions are still coupled and expected decoupling development has yet to come. By setting up different scenarios for Shenyang’s future development and conducting scenario analysis, we find that the cumulative CO2 emissions can decrease by 6.5% and 20.3% for low carbon and enhanced low carbon scenarios during 2010-2030, compared to business as usual (BAU) scenario, respectively. Furthermore, remarkable co-benefits on reducing main air pollutants are observed if greenhouse gas mitigation measures can be fully implemented, in which that the reduction of SO2 and PM10 emissions are more obvious than NOx. By considering the local realities, to reasonably control the population, optimize the energy structure, and promote the low carbon technologies could bring co-benefits so that the cities can move toward low carbon development. [Copyright &y& Elsevier]

Abstract: Using 89 major Chinese cities which comprise the case study area, this article computed the urban thermo-effect of summer in the 1990s and 2000s compared to that in the 1950s, using the database of highest monthly temperatures recorded by national weather stations from 1951 to 2007. We conducted a temporal–spatial analysis of the calculated urban thermo-effect, after which we carried out grey correlation degree analysis, system core and coritivity computation of the 22 selected indicators that could affect the urban thermo-effect. These were performed in order to determine the main factors for comprehensive analysis of urban thermo-effect. Finally, we conducted multiple regression analysis between the computed urban thermo-effect and the main factors to create the comprehensive ecological model of the urban thermo-effect. The results indicate that the urban thermo-effect in the 2000s compared to that in the 1950s is stronger than that in the 1990s. Meanwhile, the respective maximum urban thermo-effects in the 2000s and in the 1990s compared to that in the 1950s are 1.97K and 1.50K, respectively. The strong positive urban thermo-effect occurred mainly in the northeastern Chinese cities during the 1990s, while it occurred in the northwestern cities and southeastern coastal cities during the 2000s. The six main factors of the urban thermo-effect are the total size, the Gross Domestic Product (GDP), the green area, and the population of the built-up area, as well as the gross of freight and annual electricity consumption. The multiple comprehensive ecological model of the urban thermo-effect is reliable because the residual error of the created model is smaller than 0.5K. The study discovers that the mitigation of urban temperature increase is possible with the adjustment of these controllable factors. Moreover, the findings in this article could provide references to decisions made while carrying out urban planning and while implementing policies in the national and local scale. Our findings can also provide references to the urban planning and construction of other developing countries with high levels of urbanization and economic development. [Copyright &y& Elsevier]

Due to climate change and a growing urban population worldwide, cities as heat islands are of increasing concern for the health and living comfort of urban populations. Accordingly, thermal comfort is an important element of bioclimatic design within cities, and areas with an abundance of hard surfaces, and a lack of tree shade, can become uncomfortably hot in summer periods, which can negatively alter usage patterns of these spaces and even become an issue of human health. In this context, a pilot study was undertaken to assess if thermal photography of the forehead of an individual can be a reliable, non-invasive, rapid tool to predict outdoor thermal comfort. A combination of street interviews, micrometeorological measurements and facial thermography was used with 775 volunteers on warm summer days in the city of Bolzano (N Italy). Two locations were chosen with contrasting sky view factors and tree shade amounts. A large difference in the mean radiant temperature, and Universal Thermal Comfort Index (UTCI), between the two locations resulted in higher thermal sensation votes and higher levels of discomfort in the space without tree shade. The mean average forehead temperature was 1.5 °C higher in the treeless space (35.2 °C) compared to the shaded space (33.7 °C). Forehead temperatures correlated significantly positively with UTCI (treeless: r = 0.30, p < 0.001; shaded: r = 0.21, p < 0.001) and air temperature (treeless: r = 0.28, p < 0.001; shaded: r = 0.22, p < 0.001). Thermal comfort was successfully predicted from forehead temperatures in the treeless space using a logistic regression model, however low R2 values limit the predictive power of these models. Facial thermography shows promise as a proxy for thermal comfort in thermally stressful spaces. • Higher thermal sensation and discomfort were recorded in a space with less trees. • Participants overestimated air temperature more in a space with less trees. • Forehead temperatures correlated positively with air temperature and a thermal index. • Forehead temperatures exceeded 37 °C only in the space with less trees. • Facial thermography is a useful proxy for thermal comfort in thermally stressful spaces. [ABSTRACT FROM AUTHOR]

Urban cities are facing the challenges of microclimatic changes with substantially warmer environments and much less access to fresh vegetables for a healthier food supply than in adjacent rural areas. In this respect, urban rooftop agriculture is considered as a green technology for city dwellers and the community to attain environmental and socioeconomic benefits in a city. For this purpose, a roof top of 216 square meters was selected as an experimental plot where 70% of the area was covered with the selected crops (Tomato, Brinjal, Chili, Bottle Gourd and Leafy vegetables such as Spinach, Red Spinach and Water Spinach; they were cultivated under fencing panels of Bottle Gourd). The microclimatic parameters such as air temperature, near roof surface temperature, indoor temperature and relative humidity and carbon dioxide concentration from different locations of the agricultural roof and from nearby bare roofs were observed during the whole experimental period (November 2018–May 2019). Five existing rooftop gardens with green area coverages of 40, 50, 60, 80, and 85% were selected, and 5 bare nearby roofs were also selected through field visits and questionnaire surveys of 200 existing rooftop gardens. The air and ambient temperature, cooling degree day and energy saving trends were assessed for the selected roofs. The economic assessment was carried out through the net present value and internal rate of return approach of urban rooftop agriculutre. The results showed that the temperature was reduced from 1.2 to 5.5% in different area coverages of agricultural roofs with plants compared to the nearest bare roofs. For the time being, the cooling load was decreased from 3.62 to 23.73%, and energy saving was increased significantly from 5.87 to 55.63% for agricultural roofs compared to bare roofs. The study suggested that the value of urban rooftop agriculture was high environmentally and economically compared to the traditional bare roof, which would be an added amenity by the city dweller's individual motivations and state interests, and it could be aligned to achieve a more sustainable city. [ABSTRACT FROM AUTHOR]

Beliefs in climate change are influenced by personal experiences and sociodemographic characteristics; yet justice considerations are often overlooked. We unveil the influence of these factors' on climate change beliefs in a large American city facing substantial climate change impacts, Phoenix, Arizona. Using the Phoenix Area Social Survey that includes data collected from (n = 806) households across fourteen cities in the Phoenix metropolitan area, we investigate what factors influence a belief that "global warming and climate change are already occurring." Engaging adaptive capacity and justice literatures with climate belief models, we find that belief in climate change and global warming is positively associated with race specifically other than non-Hispanic Whites, high levels of education, personal experience with heat-related illnesses, and liberal beliefs. Widespread agreement about climate change is found within the scientific community, but general populations, especially in the USA, lag behind in accepting climate change. Critically, there are important justice dimensions absent in the existing literature relevant to understanding belief in and the impacts of climate change. Unpacking these factors could help inform policy makers and civil society organizations in their efforts to design more " just adaptation " strategies. • Cities in the USA have experienced a number of extreme heat events affecting locals' climate change perceptions. • We conducted fixed effects in two-level logistic regression models with a random intercept at city level to test hypotheses related to socio-demographics; heat exposure; and political beliefs in the Phoenix Metro Area. • There are significant relationships between climate change beliefs and race, education, heat-related illnesses, and liberal beliefs. • We recommend the results to be considered in the design of effective just adaptation strategies among key agents from the governments and civil society organizations. [ABSTRACT FROM AUTHOR]

• Cooling behaviours an area of increasing interest under rising heat in cities. • Survey of public in Fukuoka, Japan, assesses cooling behaviour and climate awareness. • Some people use air conditioning with mitigation focus, others emphasise adaptation. • Those emphasising mitigation have lower bills and more likely to engage in other behaviours. • Messaging on air conditioning use and promoting urban greening may enable co-benefits. Under a warming climate and urban heat island effects, cooling behaviours are increasingly important for city dwellers. Cooling actions, especially air conditioning, receive increasing scrutiny in social science, as does engagement and communication on behaviours spanning adaptation and mitigation. In response, this paper evaluates the relation between residents' adaptation and mitigation behaviours around cooling in Fukuoka, Japan, and draws lessons for communication on encouraging adaptation and mitigation actions. A survey distributed to residents in six areas of Fukuoka, Japan, assessed perceptions of global warming and urban heat island effects, frequency of mitigation and adaptation behaviours, use of air conditioning, electricity bills and evaluation of green spaces. We observe a difference between respondents using air conditioning with an energy-saving (i.e. mitigation) focus, versus those using air conditioning with an adaptation (i.e. cooling) focus. We also note residents emphasising mitigation behaviours may use shade in parks or cooling centres as alternative cooling strategies, but that awareness of effective air conditioning use may be lacking. Our findings build on existing literature by reinforcing – in a subtropical context – the need to reconsider practices around air conditioner use; and illustrate the value of a breadth of messages to promote joint mitigation and adaptation actions. [ABSTRACT FROM AUTHOR]

This paper evaluates the role of socio-cultural issues in developing climate information services that are accessible and engaging to urban communities. Two public-facing city-level climate information provision initiatives in Japan are evaluated in light of theory in environmental risk communication. The first case is Fukuoka City, Kyushu, in particular increased flood and heat risk. The second case is Tomakomai City, Hokkaido, particularly municipal data provision on potential localised climate risks related to marine environmental change. Evaluation is undertaken through in-depth interviews with local-level actors (policymakers, scientists, NGOs, citizens), and field observation in each location. The paper argues that at a stage where principles and best practices on climate information service provision are still emerging, it is crucial to avoid assumptions about what communities will want to know about climate risks. The paper hence proposes principles for more appropriate climate risk communication. These include (a) identifying which institutions citizens look to for information on local weather and climate; (b) acknowledging that publics can, in appropriate contexts, be able and willing to engage with complex information on urban climate risk; and (c) considering how data-driven information services fit with the more informal ways in which people can experience environmental change. [ABSTRACT FROM AUTHOR]

Climate change will impact urban areas. Decision makers need useful climate information to adapt adequately. This research aims to improve understanding of changes in moisture and temperature projected under climate change in Berlin compared to its surroundings. Simulations for the Representative Concentration Pathway (RCP) 8.5 scenario from the European Coordinated Regional Climate Downscaling Experiment (EURO-CORDEX) 0.11° are analyzed, showing a difference in moisture and temperature variables between Berlin and its surroundings. The running mean over 30 years shows a divergence throughout the twenty-first century for relative humidity between Berlin and its surroundings. Under this scenario, Berlin gets drier over time. The Mann-Kendall test quantifies a robust decreasing trend in relative humidity for the multi-model ensemble throughout the twenty-first century. The Mann-Whitney-Wilcoxon test for relative humidity indicates a robust climate change signal in Berlin. It is drier and warmer in Berlin compared to its surroundings for all months with the largest difference existing in summer. Additionally, the change in humidity for the period 2070–2099 compared to 1971–2000 is larger in the summer months. This study presents results to better understand near surface moisture change and related variables under long-term climate change in urban areas compared to their rural surroundings using a regional climate multi-model ensemble. [ABSTRACT FROM AUTHOR]

One of the most concerning consequences arising from the dramatic urbanization in cities is air stagnation and the related high concentration of air pollutants. Many studies have investigated the impact of urbanization on air stagnation, but few have systematically evaluated such impact and its spatial-temporal variances at the municipal scale. This study proposed an approach based on high-resolution urban climate simulations for evaluating the impact of urbanization on air stagnation. We took the city of Shenzhen in south-eastern China, a city that grew from a small fishing and farming village to a highly urbanized city in the past thirty years, as a compelling case study. Using the WRF/Noah LSM/SLUCM model, we simulated and evaluated the probability of 6-hourly air stagnation cases (ASCs) in 1979 and 2010 at the spatial resolution of 1-km 2 to demonstrate the change over a thirty-year period. Comparison results show that urbanization worsened the problem of air stagnation in Shenzhen. The number of 6-hourly ASCs has increased by 21,700 for the entire Shenzhen, and by 11.4 on average for each grid with a 1 km 2 size. A maximum increase of 458 ASCs in a grid was also observed., (Copyright © 2019. Published by Elsevier B.V.)