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Background: The increased severity of extreme weather and anticipated climate change has intensified heat stress-related mortality worldwide. This study examines the historical short-term effects of heat on mortality in Alentejo, Portugal's warmest region, and projects it up to the end of the century. Methods: Using data from 1980 to 2015 during warm seasons (May-September), the association between daily mortality by all-causes and mean temperature was examined following a case time series design, applied at both regional and subregional scales. Projections for daily temperatures were obtained from regional climate models and greenhouse gas emission scenarios (RCP4.5, RCP8.5). We also examined temporal shifts in mortality considering potential long-term and seasonal adaptative responses to heat. We then quantified the yearly effects of heat by calculating absolute and relative excess mortality from 1980 to 2015, specifically during the heatwave of 2003 (July 27 to August 15), and in future projections at 20-year intervals through 2100. Results: The analysis revealed a significant rise in mortality risk at temperatures exceeding a minimum mortality temperature (MMT) of 19.0 °C, with an exponential trend and delayed effects lasting up to 5 days. The risk increased by 413% at the maximum extreme temperature of 36.6 °C. From 1980 to 2015, 2.32% of total deaths, equating to over 5,296 deaths, were heat-associated. No significant shifts over time were noted in the population's response to heat. Future projections, without adaptation and demographic changes, show a potential increase in mortality by 15.88% under a "no mitigation policy" scenario by 2100, while mitigation measures could limit the rise to 6.61%. Conclusion: Results underscore the urgent need for protective health policies to reduce regional population vulnerability and prevent premature heat-related deaths across the century. [ABSTRACT FROM AUTHOR]

High and low daily ambient temperatures are associated with higher mortality in the general population. People experiencing homelessness (PEH) are thought to be particularly vulnerable, but there is almost no direct evidence available. We examined the temperature-mortality association among PEH in 2 populous, urban counties in hot-climate regions of the United States, focusing on heat effects. Study setting was Los Angeles County, CA, and Clark County, NV, which encompass the cities of Los Angeles and Las Vegas, respectively. Outcomes were 2015-2022 deaths among decedents categorized as homeless in county administrative records. We used quasi-Poisson distributed lag nonlinear models to estimate the association of mortality with daily temperatures and with 7-day lagged temperatures, adjusting for day of week, seasonality, and long-term trends. We estimated the minimum mortality temperature and fraction of mortality attributable to temperatures above and below minimum mortality temperature. The association between daily temperature and PEH mortality was skewed towards greater risk at higher temperatures, especially in Clark County. Temperature-attributable mortality equaled 50.1% of deaths in Clark County (95% CI, 29.0-62.8) and 7.0% in Los Angeles County (95% CI, 1.4-12.1). In both counties, most temperature-attributable deaths were attributable to heat rather than cold. In these hot-climate urban counties, our estimates of heat-attributable mortality among PEH were orders of magnitude greater than those reported in prior research on the general population. These results indicate that temperature vulnerability, particularly heat vulnerability, requires stronger public health and policy responses. This article is part of a Special Collection on Environmental Epidemiology. [ABSTRACT FROM AUTHOR]

Abstract Background The increased severity of extreme weather and anticipated climate change has intensified heat stress-related mortality worldwide. This study examines the historical short-term effects of heat on mortality in Alentejo, Portugal’s warmest region, and projects it up to the end of the century. Methods Using data from 1980 to 2015 during warm seasons (May-September), the association between daily mortality by all-causes and mean temperature was examined following a case time series design, applied at both regional and subregional scales. Projections for daily temperatures were obtained from regional climate models and greenhouse gas emission scenarios (RCP4.5, RCP8.5). We also examined temporal shifts in mortality considering potential long-term and seasonal adaptative responses to heat. We then quantified the yearly effects of heat by calculating absolute and relative excess mortality from 1980 to 2015, specifically during the heatwave of 2003 (July 27 to August 15), and in future projections at 20-year intervals through 2100. Results The analysis revealed a significant rise in mortality risk at temperatures exceeding a minimum mortality temperature (MMT) of 19.0 °C, with an exponential trend and delayed effects lasting up to 5 days. The risk increased by 413% at the maximum extreme temperature of 36.6 °C. From 1980 to 2015, 2.32% of total deaths, equating to over 5,296 deaths, were heat-associated. No significant shifts over time were noted in the population’s response to heat. Future projections, without adaptation and demographic changes, show a potential increase in mortality by 15.88% under a “no mitigation policy” scenario by 2100, while mitigation measures could limit the rise to 6.61%. Conclusion Results underscore the urgent need for protective health policies to reduce regional population vulnerability and prevent premature heat-related deaths across the century.

Extreme heat events caused by climate change and rapid urbanization are major environmental issues affecting the health of urban populations, especially in metropolitan areas. However, few studies have employed a systematic risk assessment model to delineate heat health risk (HHR) in rapidly urbanizing metropolitan areas at a finer resolution, and rare studies have used epidemiological approaches for validation, as mortality is typically considered the most crucial indicator for assessing health impact. Here, a novel integrated socio-ecological-economic index (SEEI) was used to analyze the spatial distribution and evolution of HHR with a neighborhood resolution in Shanghai from 2000 to 2020, and four heat-related mortality indicators were applied to validate. The results showed that (1) the spatial distribution of the SEEI in Shanghai exhibited significant differences between urban and suburban areas, with the main urban areas having an average SEEI 2–3 times higher than suburban areas. (2) Overall, the SEEI peaked in 2010 and declined in 2020, with very high-risk neighborhoods decreasing from seven in 2000 to none in 2020. However, there was a slight trend towards a wider range of moderate-risk neighborhoods. (3) The heat-related mortality indicators exhibited significant correlations with SEEI, demonstrating the reliability of the SEEI as also confirmed by sensitivity analysis. The SEEI used in this study can provide a basis for decision-making for Shanghai as well as similar metropolitan areas to prevent extreme heat events.

Temperature-related mortality mostly affects older people and is attributable to a combination of factors. We focussed on a key non-temperature factor – rising longevity – and aimed to quantify its reciprocal relation with temperature-related mortality risk in Spain over 1980–2018.We obtained average annual temperature-attributable deaths among people aged 65y+, by sex and age group, for different temperature ranges (extreme cold, moderate cold, moderate heat, and extreme heat), from a previous study. Combining this with population and mortality data as well as life table information, we used: (i) a counterfactual approach to assess the contribution of rising longevity to changes in the absolute risk of temperature-related mortality, and (ii) decomposition to assess the contribution of changes in temperature-related mortality to changes in longevity and its variation (lifespan inequality).Rising longevity led to considerable declines in the absolute risk of temperature-related mortality in females and males across the entire temperature range. For extreme heat, it accounted for about a 30% decrease in absolute risk (half of the total decrease over the study period). For moderate and extreme cold, it accounted for about a 20% fall in absolute risk (a quarter of the total fall). In the opposite direction, changing patterns of temperature-related deaths contributed to higher life expectancy (accounting for > 20% of the total rise in both females and males) but also higher lifespan inequality amongst older people. Most of the influence (about 80%) was via moderate cold, but declines in risk at both moderate and extreme heat led to small rises in life expectancy.Our study points to the benefits of adopting risk-reduction strategies that aim, not only at modifying hazards and reducing exposure, but that also address socially-generated vulnerability among older people. This includes ensuring that lifespans lengthen primarily through increases in years lived in good health.

Background Distributed lag non-linear models (DLNMs) are the reference framework for modelling lagged non-linear associations. They are usually used in large-scale multi-location studies. Attempts to study these associations in small areas either did not include the lagged non-linear effects, did not allow for geographically-varying risks or downscaled risks from larger spatial units through socioeconomic and physical meta-predictors when the estimation of the risks was not feasible due to low statistical power. Methods Here we proposed spatial Bayesian DLNMs (SB-DLNMs) as a new framework for the estimation of reliable small-area lagged non-linear associations, and demonstrated the methodology for the case study of the temperature-mortality relationship in the 73 neighbourhoods of the city of Barcelona. We generalized location-independent DLNMs to the Bayesian framework (B-DLNMs), and extended them to SB-DLNMs by incorporating spatial models in a single-stage approach that accounts for the spatial dependence between risks. Results The results of the case study highlighted the benefits of incorporating the spatial component for small-area analysis. Estimates obtained from independent B-DLNMs were unstable and unreliable, particularly in neighbourhoods with very low numbers of deaths. SB-DLNMs addressed these instabilities by incorporating spatial dependencies, resulting in more plausible and coherent estimates and revealing hidden spatial patterns. In addition, the Bayesian framework enriches the range of estimates and tests that can be used in both large- and small-area studies. Conclusions SB-DLNMs account for spatial structures in the risk associations across small areas. By modelling spatial differences, SB-DLNMs facilitate the direct estimation of non-linear exposure-response lagged associations at the small-area level, even in areas with as few as 19 deaths. The manuscript includes an illustrative code to reproduce the results, and to facilitate the implementation of other case studies by other researchers. [ABSTRACT FROM AUTHOR]

Abstract Background An important consequence of climate change for urban health is heat-related mortality. Vulnerable groups, especially elderly, will be the most affected. A solution put forward in many reports and policy documents is the introduction or expansion of urban green spaces. While they have a proven effect in decreasing the ambient temperature and reducing heat related mortality, the causal pathways are far from clear. Moreover, results vary for different contexts, population types and characteristics of green spaces as they are ‘complex systems thrusted into complex systems’. To our knowledge, there is no systematic synthesis of the literature that examines the mechanisms by which and the circumstances under which green spaces work to decrease heat-related mortality for elderly. Methods We performed a realist synthesis– a theory-driven review method– to develop a complexity- and context-sensitive program theory. As a first step, a causal loop diagram was constructed which describes the possible pathways through which urban green spaces influence heat-related mortality in elderly. In a second step, one of the pathways - how they may lead to a reduction of heat-related mortality by increasing social capital - was further explored for underlying mechanisms, the context in which they work and the differentiated patterns of outcomes they generate. Literature was searched for evidence supporting or contradicting the initial programme theory, resulting in a refined theory. Results Results show how urban green space can impact on heat-related mortality in elderly by its influence on their exposure to outdoor and indoor heat, by improving their resilience as well as by affecting their access to treatment. Urban green spaces and their interactions with social capital affect the access to health information, social support, and the capacity for effective lobbying. Several mechanisms help to explain these observed demi-regularities, among others perceived behavioural control, perceived usefulness, receptiveness, ontological security, and self-interest. If and how they are triggered depends on the characteristics of the urban green space, the population, and other contextual factors. Conclusion Looking into the impact of urban green spaces on heat-related mortality in elderly, researchers and policy makers should take interest in the role of social capital.

Climate change has been linked to the escalating frequency, duration, and intensity of heat waves in the Mediterranean region, intensifying health concerns for the general populace. Urban environments face elevated health risks due to concentrated populations and the urban heat island effect, further amplifying nighttime heat conditions. This study aims to project changes in heat wave characteristics and the associated population exposure risk in a large Mediterranean city, Thessaloniki, Greece. High-resolution climate simulations, using the WRF model, were conducted for three 5-year periods (2006–2010, 2046–2050, 2096–2100) under the RCP8.5 emission scenario, covering Thessaloniki with a 2 km grid. By the end of the century, Thessaloniki is projected to experience over 60 annual heat wave days, compared to ~8 in the present climate, while some episodes were found to persist beyond 30 days. The relative risk during heat wave days is expected to rise, which is primarily due to nighttime heat stress. Interestingly, the results indicate that minimum apparent temperature might be a more reliable indicator in predicting heat-related mortality compared to maximum apparent temperature. These findings emphasize the growing importance of informed heat mitigation and adaptation strategies and healthcare preparedness in urban areas facing escalating heat-related health challenges. [ABSTRACT FROM AUTHOR]

A current systematic literature review has stated several deficiencies and knowledge gaps in biometeorology research conducted in Brazil. This finding encouraged a group of local professionals in the field to foster research initiatives in topics and regions yet unexplored in the country. Motivated by that, the group organized the first Brazilian Symposium on Human Biometeorology between July 4 and 8, 2022, in Natal (RN), northeastern Brazil. This paper aims to summarize the main studies presented at the symposium and highlight a few ideas that could be pursued next in human biometeorology in future research initiatives.

Combined heat and humidity is frequently described as the main driver of human heat‐related mortality, more so than dry‐bulb temperature alone. While based on physiological thinking, this assumption has not been robustly supported by epidemiological evidence. By performing the first systematic comparison of eight heat stress metrics (i.e., temperature combined with humidity and other climate variables) with warm‐season mortality, in 604 locations over 39 countries, we find that the optimal metric for modelling mortality varies from country to country. Temperature metrics with no or little humidity modification associates best with mortality in ~40% of the studied countries. Apparent temperature (combined temperature, humidity and wind speed) dominates in another 40% of countries. There is no obvious climate grouping in these results. We recommend, where possible, that researchers use the optimal metric for each country. However, dry‐bulb temperature performs similarly to humidity‐based heat stress metrics in estimating heat‐related mortality in present‐day climate. [ABSTRACT FROM AUTHOR]

This study utilizes China’s records of non-accidental mortality along with twenty-five simulations from the NASA Earth Exchange Global Daily Downscaled Projections to evaluate forthcoming heat stress and heat-related mortality across China across four distinct scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5). The findings demonstrate a projected escalation in the heat stress index (HSI) throughout China from 2031 to 2100. The most substantial increments compared to the baseline (1995–2014) are observed under SSP5-8.5, indicating a rise of 7.96°C by the year 2100, while under SSP1-2.6, the increase is relatively modest at 1.54°C. Disparities in HSI growth are evident among different subregions, with South China encountering the most significant elevation, whereas Northwest China exhibits the lowest increment. Projected future temperatures align closely with HSI patterns, while relative humidity is anticipated to decrease across the majority of areas. The study’s projections indicate that China’s heat-related mortality is poised to surpass present levels over the forthcoming decades, spanning a range from 215% to 380% from 2031 to 2100. Notably, higher emission scenarios correspond to heightened heat-related mortality. Additionally, the investigation delves into the respective contributions of humidity and temperature to shifts in heat-related mortality. At present, humidity exerts a greater impact on fluctuations in heat-related mortality within China and its subregions. However, with the projected increase in emissions and global warming, temperature is expected to assume a dominant role in shaping these outcomes. In summary, this study underscores the anticipated escalation of heat stress and heat-related mortality across China in the future. It highlights the imperative of emission reduction as a means to mitigate these risks and underscores the variances in susceptibility to heat stress across different regions.

Temperature-related mortality mostly affects older people and is attributable to a combination of factors. We focussed on a key non-temperature factor – rising longevity – and aimed to quantify its reciprocal relation with temperature-related mortality risk in Spain over 1980–2018. We obtained average annual temperature-attributable deaths among people aged 65y+, by sex and age group, for different temperature ranges (extreme cold, moderate cold, moderate heat, and extreme heat), from a previous study. Combining this with population and mortality data as well as life table information, we used: (i) a counterfactual approach to assess the contribution of rising longevity to changes in the absolute risk of temperature-related mortality, and (ii) decomposition to assess the contribution of changes in temperature-related mortality to changes in longevity and its variation (lifespan inequality). Rising longevity led to considerable declines in the absolute risk of temperature-related mortality in females and males across the entire temperature range. For extreme heat, it accounted for about a 30% decrease in absolute risk (half of the total decrease over the study period). For moderate and extreme cold, it accounted for about a 20% fall in absolute risk (a quarter of the total fall). In the opposite direction, changing patterns of temperature-related deaths contributed to higher life expectancy (accounting for > 20% of the total rise in both females and males) but also higher lifespan inequality amongst older people. Most of the influence (about 80%) was via moderate cold, but declines in risk at both moderate and extreme heat led to small rises in life expectancy. Our study points to the benefits of adopting risk-reduction strategies that aim, not only at modifying hazards and reducing exposure, but that also address socially-generated vulnerability among older people. This includes ensuring that lifespans lengthen primarily through increases in years lived in good health. [ABSTRACT FROM AUTHOR]

Warmer global climate and urban heat islands (UHIs) interact, by exacerbating heatwaves and increasing the extreme heat days in cities. The implications of added heat stress in urban environments due to intensifying surface UHIs (SUHIs) is of utmost concern. Seasonal, annual and decadal nighttime SUHI intensities (SUHIIs), from 2001 to 2020, for nine major populated cities of India are analyzed. This includes five megacities- Delhi, Mumbai, Kolkata, Bangalore, and Chennai, and four incipient megacities- Hyderabad, Ahmedabad, Surat, and Pune. The key role of increasing urbanization (pre- and post-2010) in expansion and intensification of nighttime SUHIs in India is highlighted. For all cities either pre-monsoon (MAM) or winter (December-February; DJF) seasons show the strongest SUHII development. During the 2001–2010, and the 2011–2020 decade, a nighttime SUHII maxima of respectively (i) 2.1°C and 2.5°C for Delhi, (ii) 1.3°C and 1.5°C for Mumbai, (iii) 1.3°C and 1.5°C for Kolkata, (iv) 0.6°C and 1.0°C Bangalore, (v) 1.7°C and 1.9°C for Chennai, (vi) 1.8°C and 2.3°C for Hyderabad, (vii) 2.8°C and 3.1°C for Ahmedabad, (viii) 1.9°C and 2.4°C for Surat, and (ix) 0.8°C and 1.3°C for Pune is noted. Further, all incipient megacities showed a mean annual growth rate of nighttime SUHII of over 0.007°C/year, substantially greater than in the megacities. High SUHII magnitudes, greater growth rates of SUHII, and huge populations, severely compounds the vulnerability of Indian cities to excessive heat exposure risk, especially during MAM heatwaves. Lastly, the implications of nighttime SUHII findings from the present study, on the increase in heat stress, the loss of labor productivity and the rise in heat-related mortality rate is emphasized. The study recommends implementation of city-specific action plans to mitigate the heat stressed urban environment. Targeted use of cooling strategies in localized hotspots within the urban areas where high intensity SUHIs are likely to form is also suggested.

The present study estimates the future impact of climate change on heat-related mortality in Thessaloniki, Greece. Mortality attributed to high temperatures will increase from 0.64% (95% eCI = −1.12, 2.48) to 3.32% (95% eCI: 0.52, 6.1), whereas cold-related mortality will be reduced from 0.7% (95% eCI = −2.24, 3.31) to 0.37% (95% eCI = −1.63, 2.2). Overall, the excess total mortality attributed to temperature will be increased by 2.33% in the future. Among the elderly, high temperatures will cause 5.14% of deaths, highlighting their increased vulnerability. These findings emphasize the urgent need for targeted public health planning, mitigation, and adaptation strategies to address the health effects of climate change.

Extreme heat is one of the most important pathways illustrating the connection between climate and human health, and climate change is expected to exacerbate this public health issue. This study first used a case-crossover analysis to characterize the historical (1980–2018) association between summertime heat and non-traumatic mortality in Washington State. A separate analysis was conducted for each of the state's ten climate divisions to produce distinct exposure–response curves expressing odds of mortality as a function of humidex. Stratified analyses were used to assess the impact of age, sex, race/ethnicity, and select causes of death, and the reported results are pooled across all divisions using meta-analysis. The historical heat–mortality relationship was combined with climate projections to estimate the impact of climate change on heat-related deaths in 2030, 2050, and 2080 under two warming scenarios. The odds ratio (OR) and 95% confidence intervals of mortality at the 99th percentile of humidex compared to the 50th percentile did not include the null value in four climate divisions (E Olympic Cascade Foothills, NE Olympic San Juan, Northeastern, and Puget Sound Lowlands). The statewide odds of mortality are 8% higher (6%, 10%) on 99th percentile days compared to 50th percentile days, driven primarily by an OR of 1.09 (1.06, 1.11) in the Puget Sound Lowlands. Risk is higher for women than men and for Blacks than Whites. Risk increases with age and for diabetic, circulatory, cardiovascular, ischemic, cerebrovascular, and respiratory deaths. The 95% confidence intervals of projected heat-attributable mortality did not overlap with zero in three climate divisions (E Olympic Cascade Foothills, NE Olympic San Juan, and Puget Sound Lowlands). In these three divisions, the average percent increase in heat-attributable mortality across both warming scenarios is 35%, 35%, and 603% in 2030, 2050, and 2080, respectively. This research is the most extensive study of heat-related mortality in Washington to date and can help inform public health initiatives aiming to improve present and future health outcomes in the state. [ABSTRACT FROM AUTHOR]

Although there is a growing interest in the association between ambient temperatures and mortality, little evidence is available for Thessaloniki, the second largest city of Greece. In this study, we present an assessment of the effects of temperature on daily mortality from 2006 to 2016 in the urban area of Thessaloniki, by describing the exposure-lag-response association between temperature and cause-specific mortality with the use of a distributed lag non-linear model (DLNM). A J-shaped relationship was found between temperature and mortality. The highest values of risk were evident for respiratory (RR > 10) and cardiovascular causes (RR > 3), probably due to the fact that health status of individuals with chronic respiratory and cardiovascular diseases rapidly deteriorates during hot periods. Cold effects had longer lags of up to 15 days, whereas heat effects were short-lived, up to 4 days. Percentage change in all- and cause-specific mortality per 1 °C change above and below Minimum Mortality Temperature showed a larger increase for all-cause mortality in heat (1.95%, 95% CI: 1.07–2.84), in contrast to a smaller increase in cold (0.54%, 95% CI: 0, 1.09). Overall, 3.51% of all-cause deaths were attributable to temperature, whereas deaths attributed to heat (2.34%) were more than deaths attributed to cold (1.34%). The findings of this study present important evidence for planning public-health interventions, to reduce the health impact of extreme temperatures. [ABSTRACT FROM AUTHOR]

The occurrence of long-lasting severe heat stress, such as in July–August 2003, July 2010, or in April–May 2018 has been one of the biggest meteorological threats in Europe in recent years. The paper focuses on the biometeorological and mortality effects of the hot June that was observed in Central Europe in 2019. The basis of the study was hourly and daily Universal Thermal Climate Index (UTCI) values at meteorological stations in Poland for June 2019. The average monthly air temperature and UTCI values from 1951 to 2018 were analysed as background. Grosswetterlagen calendar of atmospheric circulation was used to assess synoptic conditions of heat wave. Several heat strain measures were applied : net heat storage (S), modelled heart rate (HR), sultriness (HSI), and UTCI index. Actual total mortality (TM) and modelled strong heat-related mortality (SHRM) were taken as indicators of biometeorological consequences of the hot June in 2019. The results indicate that prolonged persistence of unusually warm weather in June 2019 was determined by the synoptic conditions occurring over the European region and causing advection of tropical air. They led to the emergence of heat waves causing 10% increase in TM and 5 times bigger SHRM then in preceding 10 years. Such increase in SHRM was an effect of overheating and overload of circulatory system of human organism. [ABSTRACT FROM AUTHOR]

Extreme heat is one of the most important pathways illustrating the connection between climate and human health, and climate change is expected to exacerbate this public health issue. This study first used a case-crossover analysis to characterize the historical (1980–2018) association between summertime heat and non-traumatic mortality in Washington State. A separate analysis was conducted for each of the state’s ten climate divisions to produce distinct exposure–response curves expressing odds of mortality as a function of humidex. Stratified analyses were used to assess the impact of age, sex, race/ethnicity, and select causes of death, and the reported results are pooled across all divisions using meta-analysis. The historical heat–mortality relationship was combined with climate projections to estimate the impact of climate change on heat-related deaths in 2030, 2050, and 2080 under two warming scenarios. The odds ratio (OR) and 95% confidence intervals of mortality at the 99th percentile of humidex compared to the 50th percentile did not include the null value in four climate divisions (E Olympic Cascade Foothills, NE Olympic San Juan, Northeastern, and Puget Sound Lowlands). The statewide odds of mortality are 8% higher (6%, 10%) on 99th percentile days compared to 50th percentile days, driven primarily by an OR of 1.09 (1.06, 1.11) in the Puget Sound Lowlands. Risk is higher for women than men and for Blacks than Whites. Risk increases with age and for diabetic, circulatory, cardiovascular, ischemic, cerebrovascular, and respiratory deaths. The 95% confidence intervals of projected heat-attributable mortality did not overlap with zero in three climate divisions (E Olympic Cascade Foothills, NE Olympic San Juan, and Puget Sound Lowlands). In these three divisions, the average percent increase in heat-attributable mortality across both warming scenarios is 35%, 35%, and 603% in 2030, 2050, and 2080, respectively. This research is the most extensive study of heat-related mortality in Washington to date and can help inform public health initiatives aiming to improve present and future health outcomes in the state.

Although there is a growing interest in the association between ambient temperatures and mortality, little evidence is available for Thessaloniki, the second largest city of Greece. In this study, we present an assessment of the effects of temperature on daily mortality from 2006 to 2016 in the urban area of Thessaloniki, by describing the exposure-lag-response association between temperature and cause-specific mortality with the use of a distributed lag non-linear model (DLNM). A J-shaped relationship was found between temperature and mortality. The highest values of risk were evident for respiratory (RR > 10) and cardiovascular causes (RR > 3), probably due to the fact that health status of individuals with chronic respiratory and cardiovascular diseases rapidly deteriorates during hot periods. Cold effects had longer lags of up to 15 days, whereas heat effects were short-lived, up to 4 days. Percentage change in all- and cause-specific mortality per 1 °C change above and below Minimum Mortality Temperature showed a larger increase for all-cause mortality in heat (1.95%, 95% CI: 1.07–2.84), in contrast to a smaller increase in cold (0.54%, 95% CI: 0, 1.09). Overall, 3.51% of all-cause deaths were attributable to temperature, whereas deaths attributed to heat (2.34%) were more than deaths attributed to cold (1.34%). The findings of this study present important evidence for planning public-health interventions, to reduce the health impact of extreme temperatures.

Abstract Exposure to high ambient temperatures is an important cause of avoidable, premature death that may become more prevalent under climate change. Though extensive epidemiological data are available in the United States, they are largely limited to select large cities, and hence, most projections estimate the potential impact of future warming on a subset of the U.S. population. Here we utilize evaluations of the relative risk of premature death associated with temperature in 10 U.S. cities spanning a wide range of climate conditions to develop a generalized risk function. We first evaluate the performance of this generalized function, which introduces substantial biases at the individual city level but performs well at the large scale. We then apply this function to estimate the impacts of projected climate change on heat‐related nationwide U.S. deaths under a range of scenarios. During the current decade, there are 12,000 (95% confidence interval 7,400–16,500) premature deaths annually in the contiguous United States, much larger than most estimates based on totals for select individual cities. These values increase by 97,000 (60,000–134,000) under the high‐warming Representative Concentration Pathway (RCP) 8.5 scenario and by 36,000 (22,000–50,000) under the moderate RCP4.5 scenario by 2100, whereas they roughly double under the aggressive mitigation scenario RCP2.6. These results include estimates of adaptation that reduce impacts by ~40–45% as well as population increases that roughly offset adaptation. The results suggest that the degree of climate change mitigation will have important health impacts on Americans.

Climate change is considered to have great impact on human health. The heat waves have been associated with excess morbidity and mortality of cardiovascular diseases (CVD) across various populations and geographic locations. Important role in the heat-induced cardiovascular damage has endothelial dysfunction. It has been noticed that hot weather can impair tone and structure of the blood vessels via interfering with variety of biological factors such as nitric oxide synthesize, cytokine production and systemic inflammation. Also, due to dehydration and increased blood viscosity, by promoting thrombogenesis, heat has important impact on patients with atherosclerosis. During chronic exposure to the cold or hot weather cardiovascular function can be decreased, leading to a higher risk of developing heart attack, malignant cardiac arrhythmias, thromboembolic diseases and heat-induced sepsis like shock. It has been shown that changes in the ambient temperature through increasing blood pressure, blood viscosity, and heart rate, contribute to the cardiovascular mortality. The majority of deaths due to heat waves especially affect individuals with preexisting chronic CVD. This population can experience a decline in the health status, since extreme ambient temperature affects pharmacokinetic parameters of many cardiovascular drugs. Increased mortality from ischemic or hemorrhagic stroke can also be related to extreme temperature variations. On a cellular level, higher ambient temperature can limit storage of ATP and O2 increase amount of free radicals and toxic substances and induce neuronal apoptotic signal transduction, which all can lead to a stroke. Preserving cardiovascular function in context of extreme climate changing tends to be particularly challenging. [ABSTRACT FROM AUTHOR]

To provide a simple high-resolution heat-stress forecast for Seoul, Korea, we coupled a high-resolution climate simulation (25 m grid spacing) for an average heat day with the operational forecasting model (5 km grid spacing). Thereby, we accounted for the meso-scale weather conditions and local-scale air temperature induced by land cover and the urban heat island effect. Moreover, we estimated the impacts of heat events using heat-related mortality rate. Applying the simple high-resolution heat-stress forecast for July and August 2016, we detected a substantial spatial variability in maximum air temperature and heat-related mortality rate in Seoul. The evaluation of simulated maximum air temperature compared to observations revealed a small deviation (MB = 0.11 K, RMSD = 1.40 K). Despite the limitation of using average conditions, it was an efficient way to identify particularly affected areas, neighbourhoods, and districts for releasing more location-specific heat-stress warnings. [ABSTRACT FROM AUTHOR]

Exposure to high ambient temperatures is an important cause of avoidable, premature death that may become more prevalent under climate change. Though extensive epidemiological data are available in the United States, they are largely limited to select large cities, and hence, most projections estimate the potential impact of future warming on a subset of the U.S. population. Here we utilize evaluations of the relative risk of premature death associated with temperature in 10 U.S. cities spanning a wide range of climate conditions to develop a generalized risk function. We first evaluate the performance of this generalized function, which introduces substantial biases at the individual city level but performs well at the large scale. We then apply this function to estimate the impacts of projected climate change on heat‐related nationwide U.S. deaths under a range of scenarios. During the current decade, there are 12,000 (95% confidence interval 7,400–16,500) premature deaths annually in the contiguous United States, much larger than most estimates based on totals for select individual cities. These values increase by 97,000 (60,000–134,000) under the high‐warming Representative Concentration Pathway (RCP) 8.5 scenario and by 36,000 (22,000–50,000) under the moderate RCP4.5 scenario by 2100, whereas they remain statistically unchanged under the aggressive mitigation scenario RCP2.6. These results include estimates of adaptation that reduce impacts by ~40–45% as well as population increases that roughly offset adaptation. The results suggest that the degree of climate change mitigation will have important health impacts on Americans. Key Points: We develop a generalized risk function from U.S. epidemiological data to quantify nationwide heat‐related premature deathsWe find ~12,000 premature deaths annually in the contiguous United States during the 2010sProjected deaths rise to ~110,000 and ~50,000 year−1 under high‐ and moderate‐warming scenarios, respectively, including population growth [ABSTRACT FROM AUTHOR]

We compared selected thermal indices in their ability to predict heat-related mortality in Prague, Czech Republic, during the extraordinary summer 2015. Relatively, novel thermal indices—Universal Thermal Climate Index and Excess Heat Factor (EHF)—were compared with more traditional ones (apparent temperature, simplified wet-bulb globe temperature (WBGT), and physiologically equivalent temperature). The relationships between thermal indices and all-cause relative mortality deviations from the baseline (excess mortality) were estimated by generalized additive models for the extended summer season (May–September) during 1994–2014. The resulting models were applied to predict excess mortality in 2015 based on observed meteorology, and the mortality estimates by different indices were compared. Although all predictors showed a clear association between thermal conditions and excess mortality, we found important variability in their performance. The EHF formula performed best in estimating the intensity of heat waves and magnitude of heat-impacts on excess mortality on the most extreme days. Afternoon WBGT, on the other hand, was most precise in the selection of heat-alert days during the extended summer season, mainly due to a relatively small number of "false alerts" compared to other predictors. Since the main purpose of heat warning systems is identification of days with an increased risk of heat-related death rather than prediction of exact magnitude of the excess mortality, WBGT seemed to be a slightly favorable predictor for such a system. [ABSTRACT FROM AUTHOR]

Rising environmental temperatures represent a major threat to human health. The activation of heat advisories using evidence-based thresholds for high-risk outdoor ambient temperatures have been shown to be an effective strategy to save lives during hot weather. However, although the relationship between weather and human health has been widely defined by outdoor temperature, corresponding increases in indoor temperature during heat events can also be harmful to health especially in vulnerable populations. In this review, we discuss our current understanding of the relationship between outdoor temperature and human health and examine how human health can also be adversely influenced by high indoor temperatures during heat events. Our assessment of the existing literature revealed a high degree of variability in what can be considered an acceptable indoor temperature because there are differences in how different groups of people may respond physiologically and behaviorally to the same living environment. Finally, we demonstrate that both non-physiological (e.g., geographical location, urban density, building design) and physiological (e.g., sex, age, fitness, state of health) factors must be considered when defining an indoor temperature threshold for preserving human health in a warming global climate. [ABSTRACT FROM AUTHOR]

This article presents a customized system dynamics model to facilitate the informed development of policy for urban heat island mitigation within the context of future climate change, and with special emphasis on the reduction of heat-related mortality. The model incorporates a variety of components (incl.: the urban heat island effect; population dynamics; climate change impacts on temperature; and heat-related mortality) and is intended to provide urban planning and related professionals with: a facilitated means of understanding the risk of heat-related mortality within the urban heat island; and location-specific information to support the development of reasoned and targeted urban heat island mitigation policy.

Abstract Background Excessive summer heat is a serious environmental health problem in Skopje, the capital and largest city of the former Yugoslav Republic of Macedonia. This paper attempts to forecast the impact of heat on mortality in Skopje in two future periods under climate change and compare it with a historical baseline period. Methods After ascertaining the relationship between daily mean ambient air temperature and daily mortality in Skopje, we modelled the evolution of ambient temperatures in the city under a Representative Concentration Pathway scenario (RCP8.5) and the evolution of the city population in two future time periods: 2026–2045 and 2081–2100, and in a past time period (1986–2005) to serve as baseline for comparison. We then calculated the projected average annual mortality attributable to heat in the absence of adaptation or acclimatization during those time windows, and evaluated the contribution of each source of uncertainty on the final impact. Results Our estimates suggest that, compared to the baseline period (1986–2005), heat-related mortality in Skopje would more than double in 2026–2045, and more than quadruple in 2081–2100. When considering the impact in 2081–2100, sampling variability around the heat–mortality relationship and climate model explained 40.3 and 46.6 % of total variability. Conclusion These results highlight the importance of a long-term perspective in the public health prevention of heat exposure, particularly in the context of a changing climate.

Since 2001, a synthesizing element in Intergovernmental Panel on Climate Change assessment reports has been a summary of how risks in a particular system could change with additional warming above pre-industrial levels, generally accompanied by a figure called the burning embers. We present a first effort to develop burning embers for climate change risks for heat-related morbidity and mortality, ozone-related mortality, malaria, diseases carried by Aedes sp., Lyme disease, and West Nile fever. We used an evidence-based approach to construct the embers based on a comprehensive global literature review. Projected risks for these health outcomes under 1.5 °C, 2 °C, and >2 °C of warming were used to estimate at what temperatures risk levels increased from undetectable to medium, high, and very high, from the pre-industrial baseline, under three adaptation scenarios. Recent climate change has likely increased risks from undetectable to moderate for heat-related morbidity and mortality, ozone-related mortality, dengue, and Lyme disease. Recent climate change also was assessed as likely beginning to affect the burden of West Nile fever. A detectable impact of climate change on malaria is not yet apparent but is expected to occur with additional warming. The risk for each climate-sensitive health outcome is projected to increase as global mean surface temperature increases above pre-industrial levels, with the extent and pace of adaptation expected to affect the timing and magnitude of risks. The embers may be an effective tool for informing efforts to build climate-resilient health systems including through vulnerability, capacity, and adaptation assessments and the development of national adaptation plans. The embers also can be used to raise awareness of future threats from climate change and advocate for mitigation actions to reduce the overall magnitude of health risks later this century and to expand current adaptation efforts to protect populations now.

Urban vegetation provides undeniable benefits to urban climate, health, thermal comfort and environmental quality of cities and represents one of the most considered urban heat mitigation measures. Despite the plethora of available scientific information, very little is known about the holistic and global impact of a potential increase of urban green infrastructure (GI) on urban climate, environmental quality and health, and their synergies and trade-offs. There is a need to evaluate globally the extent to which additional GI provides benefits and quantify the problems arising from the deployment of additional greenery in cities which are usually overlooked or neglected. The present paper has reviewed and analysed 55 fully evaluated scenarios and case studies investigating the impact of additional GI on urban temperature, air pollution and health for 39 cities. Statistically significant correlations between the percentage increase of the urban GI and the peak daily and night ambient temperatures are obtained. The average maximum peak daily and night-time temperature drop may not exceed 1.8 and 2.3 °C respectively, even for a maximum GI fraction. In parallel, a statistically significant correlation between the peak daily temperature decrease caused by higher GI fractions and heat-related mortality is found. When the peak daily temperature drops by 0.1 °C, then the percentage of heat-related mortality decreases on average by 3.0% The impact of additional urban GI on the concentration of urban pollutants is analysed, and the main parameters contributing to decrease or increase of the pollutants’ concentration are presented.

This study quantifies heat-stress hazard (air temperature), vulnerability (heat vulnerability index and age score), and risk (heat-related mortality) on the district scale in Seoul, Korea, for a comprehensive heat-stress impact assessment. Moreover, the heat-stress impact assessment is evaluated by checking the spatial consistency between heat-stress hazard, vulnerability, and risk, which was rarely done before. We applied numerical and geo-empirical models to simulate the spatial pattern of heat-stress hazard. For heat-stress vulnerability, we used demographic and socioeconomic factors. Heat-related mortality was estimated based on an event-based heat-stress risk analysis. Results are that heat-stress hazard, vulnerability, and risk are spatially variable in Seoul. The highest heat-stress hazard was detected in the districts Mapo, Yeongdeungpo, and Yangcheon, the highest vulnerability in Jongno and the highest risk in Jongno and Yangcheon. The different components (heat-stress hazard, vulnerability, and risk) and variables (heat vulnerability index and percentage of seniors) showed different spatial patterns. Knowledge about the causes of higher heat-stress risk, either the hazard or vulnerability, is helpful to design tailored adaptation measures that focus on the reduction of thermal loads or on the preparation of the vulnerable population. The evaluation showed that heat-stress vulnerability and hazard explain the spatial pattern of risk only partly. This highlights the need to evaluate heat-stress impact assessment systems to produce reliable urban heat-stress maps. [ABSTRACT FROM AUTHOR]

Heat-related morbidity and mortality are recognized as public health threat. However, little evidence has been reported for cause-specific mortality from heat. The aims of this study is to explore trends in diseases of heat-related mortality in the northeast among selected specific-cause mortality, in the Northeast Thailand. We used a national database from the Strategy Planning Division, Ministry of Public Health for cause-specific mortality from heat in 4 groups including malignant neoplasm, diseases of the circulatory system, diseases of the respiratory system, diseases of the genitourinary system. Daily weather data provided by the Meteorological Department included temperature, humidity, precipitation, and wind speed for twenty provinces in the northeastern region of Thailand from 2006 to 2015. Joinpoint regression analysis and Poisson regression model was used for estimation the effect of heat on mortality. Results, the trend of annual specific-cause mortality increased with the Annual Percent Change (APC) of 7.74% of Malignant neoplasm, 9.80% for diseases of respiratory system, 12.03% for diseases of the circulatory system and 2.16% for diseases of the genitourinary system. A one-degree Celsius increase with the daily mean temperature was significantly associated with a 16% risk in all included mortalities used as an indicator for heat-related mortality (95% CI IRR= 1.11-1.21, p-value =<0.001), A one-degree Celsius increase in the daily maximum temperature was significantly associated with a 9% decreased risk in the same mortality (95% CI IRR=0.88-0.96, p-value < 0.001). In conclusion, trend analysis showed that heat-related mortality increased significantly during the period. Increased in daily temperature were positively associated with mortality in the northeast of Thailand. This suggested that there is a need to initiate any public health prevention and climate change adaptation from heat as to reduce the adverse effects of heat extremes on health. [ABSTRACT FROM AUTHOR]