Heat and health in Antwerp under climate change: Projected impacts and implications for prevention

Mitigation potential of urban greening during heatwaves and stormwater events: a modeling study for Karlsruhe, Germany

Climate change is increasing the frequency and intensity of urban heat islands and stormwater flooding. In order to mitigate these threats cities are turning toward green infrastructure to restore the hydrologic cycle in a way that increases the ecosystem services provided by trees. Strategically designed green infrastructure can mitigate runoff volume by rainfall interception through tree canopies and redirect impervious runoff into bioswales that promote infiltration. In addition, urban greens mitigate extreme heat via evapotranspiration and shading. Here we applied the i-Tree HydroPlus model to the German city of Karlsruhe and its twenty-seven districts with varying initial conditions of tree cover to analyze the potential for both runoff and heat mitigation during dry and wet periods throughout a 5-year period. After analyzing initial tree cover and drainage conditions, we used the model to simulate a green infrastructure scenario for each district with restored hydrology and tree cover at 30%. Regarding trade-offs between runoff and heat mitigation, the results confirm that dry soils before storm events lead to greater runoff reduction by 10%, and wet soils prior to heatwaves resulted in a greater evaporative cooling. Compared to current conditions, the green infrastructure scenarios resulted in decreasing the number of extreme heat hours (Heat Index > 31 °C) per year on average by 64.5%, and to reduce runoff in average by 58% across all city districts. Thus, our simulation results show that investing into a greener infrastructure, has positive impacts on microclimate and hydrology. Finally, we discuss synergies and trade-offs of the investigated management options as well as the transferability of results to other cities.

Associations of heat with diseases and specific symptoms in Flanders, Belgium: An 8-year retrospective study of general practitioner registration data

INTRODUCTION

Global temperature rise has become a major health concern. Most previous studies on the impact of heat on morbidity have used hospital data.

OBJECTIVE

This study aimed to quantify the association between ambient temperature and a variety of potentially heat-related medical conditions and symptoms using general practitioner (GP) data, in Flanders, Belgium.

METHODS

We used eight years (2012-2019) of aggregated data of daily GP visits during the Belgian summer period (May-September). A distributed lag nonlinear model (DLNM) with time-stratified conditional quasi-Poisson regression was used to account for the non-linear and delayed effect of temperature indicators (minimum, mean and maximum). We controlled for potential confounders such as particulate matter, humidity, and ozone.

RESULTS

The overall (lag0-14) association between heat and most of the outcomes was J-shaped, with an increased risk of disease observed at higher temperatures. The associations were more pronounced using the minimum temperatures indicator. Comparing the 99th (20 °C) to the minimum morbidity temperature (MMT) of the minimum temperature distribution during summer, the relative risk (RR) was significantly higher for heat-related general symptoms (RR = 1.30 [95 % CI: 1.07, 1.57]), otitis externa (RR = 4.87 [95 % CI:2.98, 7.98]), general heart problems (RR = 2.43 [95 % CI: 1.33, 4.42]), venous problems (RR = 2.48 [95 % CI:1.55, 3.96]), respiratory complaints (RR = 1.97 [95 % CI: 1.25, 3.09]), skin problems (RR = 3.26 [95 % CI: 2.51, 4.25]), and urinary infections (RR = 1.37 [95 % CI: 1.11, 1.69]). However, we did not find evidence for heat-related increases in gastrointestinal problems, cerebrovascular events, cardiovascular events, arrhythmia, mental health problems, upper respiratory problems and lower respiratory problems. An increased risk of allergy was observed when the minimum temperature reached 17.8 °C (RR = 1.50 [95 % CI: 1.23, 1.83]). Acute effects of heat were observed (largest effects at the first few lags).

SUMMARY

Our findings indicated that the occurrence of certain symptoms and illnesses during summer season is associated to high temperature or environmental exposures that are augmented by elevated temperatures. Overall, unlike hospitalization data, GP visits data provide broader population coverage, revealing a more accurate representation of heat-health association.

Drivers of associations between daytime-nighttime compound temperature extremes and mortality in China

BACKGROUND

Temperature extremes are anticipated to become more frequent and more intense under the context of climate change. While current evidence on health effects of compound extreme temperature event is scarce.

METHODS

This nationwide cross-sectional study collected daily data on weather and mortality for 161 Chinese districts/counties during 2007-2013. A quasi-Poisson generalized linear model was first applied to assess effects of daytime-only, nighttime-only and compound daytime-nighttime heat wave (and cold spell) on cause-specific mortality. Then a random-effect meta-analysis was used to produce pooled estimates at national level. Stratification analyses were performed by relative humidity, individual and regional characteristics.

RESULTS

Here we show that mortality risks of compound daytime-nighttime temperature extremes are much higher than those occurring only in the daytime or nighttime. Humid weather further exaggerates the mortality risk during heat waves, while dry air enhances the risk during cold weather. People who are elderly, illiterate, and those with ischemic heart disease and respiratory disease are particularly vulnerable to extreme temperature. At the community-level, population size, urbanization rate, proportion of elderly and PM2.5 are positively associated with increased risks associated with heat waves. Temperature, humidity and normalized difference vegetation index are positively associated with the effects of cold weather, with an opposite trend for latitude and diurnal temperature range.

CONCLUSIONS

This nationwide study highlights the importance of incorporating compound daytime-nighttime extreme temperature events and humid conditions into early warning systems and urban design/planning.

Accounting for adaptation when projecting climate change impacts on health: A review of temperature-related health impacts

Exposure to high and low ambient temperatures can cause harm to human health. Due to global warming, heat-related health effects are likely to increase substantially in future unless populations adapt to living in a warmer world. Adaptation to temperature may occur through physiological acclimatisation, behavioural mechanisms, and planned adaptation. A fundamental step in informing responses to climate change is understanding how adaptation can be appropriately accounted for when estimating future health burdens. Previous studies modelling adaptation have used a variety of methods, and it is often unclear how underlying assumptions of adaptation are made and if they are based on evidence. Consequently, the most appropriate way to quantitatively model adaptation in projections of health impacts is currently unknown. With increasing interest from decisionmakers around implementation of adaptation strategies, it is important to consider the role of adaptation in anticipating future health burdens of climate change. To address this, a literature review using systematic scoping methods was conducted to document the quantitative methods employed by studies projecting future temperature-related health impacts under climate change that also consider adaptation. Approaches employed in studies were coded into methodological categories. Categories were discussed and refined between reviewers during synthesis. Fifty-nine studies were included and grouped into eight methodological categories. Methods of including adaptation in projections have changed over time with more recent studies using a combination of approaches or modelling adaptation based on specific adaptation strategies or socioeconomic conditions. The most common approaches to model adaptation are heat threshold shifts and reductions in the exposure-response slope. Just under 20% of studies were identified as using an intervention-based empirical basis for statistical assumptions. Including adaptation in projections considerably reduced the projected temperature-mortality burden in the future. Researchers should ensure that all future impact assessments include adaptation uncertainty in projections and assumptions are based on empirical evidence.

Climate Change, Summer Temperature, and Heat-Related Mortality in Finland: Multicohort Study with Projections for a Sustainable vs. Fossil-Fueled Future to 2050

BACKGROUND

Climate change scenarios illustrate various pathways in terms of global warming ranging from "sustainable development" (Shared Socioeconomic Pathway SSP1-1.9), the best-case scenario, to 'fossil-fueled development' (SSP5-8.5), the worst-case scenario.

OBJECTIVES

We examined the extent to which increase in daily average urban summer temperature is associated with future cause-specific mortality and projected heat-related mortality burden for the current warming trend and these two scenarios.

METHODS

We did an observational cohort study of 363,754 participants living in six cities in Finland. Using residential addresses, participants were linked to daily temperature records and electronic death records from national registries during summers (1 May to 30 September) 2000 to 2018. For each day of observation, heat index (average daily air temperature weighted by humidity) for the preceding 7 d was calculated for participants' residential area using a geographic grid at a spatial resolution of 1 km × 1 km . We examined associations of the summer heat index with risk of death by cause for all participants adjusting for a wide range of individual-level covariates and in subsidiary analyses using case-crossover design, computed the related period population attributable fraction (PAF), and projected change in PAF from summers 2000-2018 compared with those in 2030-2050.

RESULTS

During a cohort total exposure period of 582,111,979 summer days (3,880,746 person-summers), we recorded 4,094 deaths, including 949 from cardiovascular disease. The multivariable-adjusted rate ratio (RR) for high (≥ 21 ° C ) vs. reference (14 - 15 ° C ) heat index was 1.70 (95% CI: 1.28, 2.27) for cardiovascular mortality, but it did not reach statistical significance for noncardiovascular deaths, RR = 1.14 (95% CI: 0.96, 1.36), a finding replicated in case-crossover analysis. According to projections for 2030-2050, PAF of summertime cardiovascular mortality attributable to high heat will be 4.4% (1.8%-7.3%) under the sustainable development scenario, but 7.6% (3.2%-12.3%) under the fossil-fueled development scenario. In the six cities, the estimated annual number of summertime heat-related cardiovascular deaths under the two scenarios will be 174 and 298 for a total population of 1,759,468 people.

DISCUSSION

The increase in average urban summer temperature will raise heat-related cardiovascular mortality burden. The estimated magnitude of this burden is > 1.5 times greater if future climate change is driven by fossil fuels rather than sustainable development. https://doi.org/10.1289/EHP12080.

The contribution of demographic changes to future heat-related health burdens under climate change scenarios

Anthropogenic climate change will have a detrimental impact on global health, including the direct impact of higher ambient temperatures. Existing projections of heat-related health outcomes in a changing climate often consider increasing ambient temperatures alone. Population growth and structure has been identified as a key source of uncertainty in future projections. Age acts as a modifier of heat risk, with heat-risk generally increasing in older age-groups. In many countries the population is ageing as lower birth rates and increasing life expectancy alter the population structure. Preparing for an older population, in particular in the context of a warmer climate should therefore be a priority in public health research and policy. We assess the level of inclusion of population growth and demographic changes in research projecting exposure to heat and heat-related health outcomes. To assess the level of inclusion of population changes in the literature, keyword searches of two databases were implemented, followed by reference and citation scans to identify any missed papers. Relevant papers, those including a projection of the heat health burden under climate change, were then checked for inclusion of population scenarios. Where sensitivity to population change was studied the impact of this on projections was extracted. Our analysis suggests that projecting the heat health burden is a growing area of research, however, some areas remain understudied including Africa and the Middle East and morbidity is rarely explored with most studies focusing on mortality. Of the studies pairing projections of population and climate, specifically SSPs and RCPs, many used pairing considered to be unfeasible. We find that not including any projected changes in population or demographics leads to underestimation of health burdens of on average 64 %. Inclusion of population changes increased the heat health burden across all but two studies.

Achievements and gaps in projection studies on the temperature-attributable health burden: Where should we be headed?

Future projection of the temperature-related health burden, including mortality and hospital admissions, is a growing field of research. These studies aim to provide crucial information for decision-makers considering existing health policies as well as integrating targeted adaptation strategies to evade the health burden. However, this field of research is still overshadowed by large uncertainties. These uncertainties exist to an extent in the future climate and population models used by such studies but largely in the disparities in underlying assumptions. Existing studies differ in the factors incorporated for projection and strategies for considering the future adaptation of the population to temperature. These differences exist to a great degree because of a lack of robust evidence as well as gaps in the field of climate epidemiology that still require extensive input from the research community. This narrative review summarizes the current status of projection studies of temperature-attributable health burden, the guiding assumptions behind them, the common grounds, as well as the differences. Overall, the review aims to highlight existing evidence and knowledge gaps as a basis for designing future studies on temperature-attributable health burden estimation. Finding a robust methodology for projecting the future health burden could be a milestone for climate epidemiologists as this would largely benefit the world when applying this technique to project the climate-attributable cause-specific health burden and adapt our existing health policies accordingly.

Association between temperature and natural mortality in Belgium: Effect modification by individual characteristics and residential environment

BACKGROUND

There is strong evidence of mortality being associated to extreme temperatures but the extent to which individual or residential factors modulate this temperature vulnerability is less clear.

METHODS

We conducted a multi-city study with a time-stratified case-crossover design and used conditional logistic regression to examine the association between extreme temperatures and overall natural and cause-specific mortality. City-specific estimates were pooled using a random-effect meta-analysis to describe the global association. Cold and heat effects were assessed by comparing the mortality risks corresponding to the 2.5th and 97.5th percentiles of the daily temperature, respectively, with the minimum mortality temperature. For cold, we cumulated the risk over lags of 0 to 28 days before death and 0 to 7 days for heat. We carried out stratified analyses and assessed effect modification by individual characteristics, preexisting chronic health conditions and residential environment (population density, built-up area and air pollutants: PM2.5, NO2, O3 and black carbon) to identify more vulnerable population subgroups.

RESULTS

Based on 307,859 deaths from natural causes, we found significant cold effect (OR = 1.42, 95%CI: 1.30-1.57) and heat effect (OR = 1.17, 95%CI: 1.12-1.21) for overall natural mortality and for respiratory causes in particular. There were significant effects modifications for some health conditions: people with asthma were at higher risk for cold, and people with psychoses for heat. In addition, people with long or frequent hospital admissions in the year preceding death were at lower risk. Despite large uncertainties, there was suggestion of effect modification by air pollutants: the effect of heat was higher on more polluted days of O3 and black carbon, and a higher cold effect was observed on more polluted days of PM2.5 and NO2 while for O3, the effect was lower.

CONCLUSIONS

These findings allow for targeted planning of public-health measures aiming to prevent the effects of extreme temperatures.

Systematic review of the impact of heatwaves on health service demand in Australia

OBJECTIVES

Heatwaves have been linked to increased levels of health service demand in Australia. This systematic literature review aimed to explore health service demand during Australian heatwaves for hospital admissions, emergency department presentations, ambulance call-outs, and risk of mortality.

STUDY DESIGN

A systematic review to explore peer-reviewed heatwave literature published from 2000 to 2020.

DATA SOURCES

Articles were reviewed from six databases (MEDLINE, Scopus, Web of Science, PsychINFO, ProQuest, Science Direct). Search terms included: heatwave, extreme heat, ambulance, emergency department, and hospital. Studies were included if they explored heat for a period of two or more consecutive days. Studies were excluded if they did not define a threshold for extreme heat or if they explored data only from workers compensation claims and major events.

DATA SYNTHESIS

This review was prospectively registered with PROSPERO (# CRD42021227395 ). Forty-five papers were included in the final review following full-text screening. Following a quality assessment using the GRADE approach, data were extracted to a spreadsheet and compared. Significant increases in mortality, as well as hospital, emergency, and ambulance demand, were found across Australia during heatwave periods. Admissions for cardiovascular, renal, respiratory, mental and behavioural conditions exhibited increases during heatwaves. The most vulnerable groups during heatwaves were children (< 18 years) and the elderly (60+).

CONCLUSIONS

Heatwaves in Australia will continue to increase in duration and frequency due to the effects of climate change. Health planning is essential at the community, state, and federal levels to mitigate the impacts of heatwaves on health and health service delivery especially for vulnerable populations. However, understanding the true impact of heatwaves on health service demand is complicated by differing definitions and methodology in the literature. The Excess Heat Factor (EHF) is the preferred approach to defining heatwaves given its consideration of local climate variability and acclimatisation. Future research should explore evidence-based and spatially relevant heatwave prevention programs. An enhanced understanding of heatwave health impacts including service demand will inform the development of such programs which are necessary to promote population and health system resilience.

Impact of Short-Term Exposure to Extreme Temperatures on Mortality: A Multi-City Study in Belgium

In light of climate change, health risks are expected to be exacerbated by more frequent high temperatures and reduced by less frequent cold extremes. To assess the impact of different climate change scenarios, it is necessary to describe the current effects of temperature on health. A time-stratified case-crossover design fitted with conditional quasi-Poisson regressions and distributed lag non-linear models was applied to estimate specific temperature-mortality associations in nine urban agglomerations in Belgium, and a random-effect meta-analysis was conducted to pool the estimates. Based on 307,859 all-cause natural deaths, the mortality risk associated to low temperature was 1.32 (95% CI: 1.21-1.44) and 1.21 (95% CI: 1.08-1.36) for high temperature relative to the minimum mortality temperature (23.1 °C). Both cold and heat were associated with an increased risk of cardiovascular and respiratory mortality. We observed differences in risk by age category, and women were more vulnerable to heat than men. People living in the most built-up municipalities were at higher risk for heat. Air pollutants did not have a confounding effect. Evidence from this study helps to identify specific populations at risk and is important for current and future public health interventions and prevention strategies.

Evolution of the minimum mortality temperature (1983-2018): Is Spain adapting to heat?

The objective of this study was to analyze at the level of Spain's 52 provinces province level the temporal evolution of minimum mortality temperatures (MMT) from 1983 to 2018, in order to determine whether the increase in MMT would be sufficient to compensate for the increase in environmental temperatures in Spain for the period. It also aimed to analyze whether the rate of evolution of MMT would be sufficient, were it to remain constant, to compensate for the predicted increase in temperatures in an unfavorable (RCP 8.5) emissions scenario for the time horizon 2051-2100. The independent variable was made up of maximum daily temperature data (Tmax) for the summer months in the reference observatories of each province for the 1983-2018 period. The dependent variable was daily mortality rate due to natural causes (ICD 10: A00-R99). For each year and province, MMT was determined using a quadratic or cubic fit (p < 0.05). Based on the annual MMT values, a linear fit was carried out that allowed for determining the time evolution of MMT. These values were compared with the evolution of Tmax registered in each observatory during the 1983-2018 analyzed period and with the predicted values of Tmax obtained for an RCP8.5 scenario for the period 2051-2100. The rate of global variance in Tmax in the summer months in Spain during the 1983-2018 period was 0.41 °C/decade, while MMT across the whole country increased at a rate of 0.64 °C/decade. Variations in the provinces were heterogeneous. For the 2051-2100 time horizon, there was predicted increase in Tmax values of 0.66 °C/decade, with marked geographical differences. Although at the global level it is possible to speak of adaptation, the heterogeneities among the provinces suggest that the local level measures are needed in order to facilitate adaptation in those areas where it is not occurring.

Projections of temperature-related cause-specific mortality under climate change scenarios in a coastal city of China

BACKGROUND

Numerous studies have been conducted to project temperature-related mortality under climate change scenarios. However, most of the previous evidence has been limited to the total or non-accidental mortality, resulting in insufficient knowledge on the influence of climate change on different types of disease.

OBJECTIVES

We aimed to project future temperature impact on mortality from 16 causes under multiple climate change models in a coastal city of China.

METHODS

We first estimated the baseline exposure-response relationships between daily average temperature and cause-specific mortality during 2009-2018. Then, we acquired downscaled future temperature projections from 28 general circulation models (GCMs) under two Representative Concentration Pathway (RCP4.5 and RCP8.5). Finally, we combined these exposure-response associations with projected temperature to estimate the change in the temperature-related death burden in different future decades in comparison to the 2010 s, assuming no demographic changes and population acclimatization.

RESULTS

We found a consistently decreasing trend in cold-related mortality but a steep rise in heat-related mortality among 16 causes under climate change scenarios. Compared with the 2010 s, the net change in the fraction of total mortality attributable to temperature are projected to -0.54% (95% eCI: -1.69% to 0.71%) and -0.38% (95% eCI: -2.73% to 2.12%) at the end of the 21st century under RCP4.5 and RCP8.5, respectively. However, the magnitude of future cold and heat effects varied by different causes of death. A net reduction of future temperature-related death burden was observed among 10 out of 15 causes, with estimates ranging from -5.02% (95% eCI: -17.42% to 2.50%) in mental disorders to -1.01% (95% eCI: -5.56% to 3.28%) in chronic lower respiratory disease. Conversely, the rest diseases are projected to experience a potential net increase of temperature-related death burden, with estimates ranging from 0.44% (95% eCI: -4.40% to 6.02%) in ischemic heart disease and 4.80% (95% eCI: -0.04% to 9.84%) in external causes.

CONCLUSIONS

Our study indicates that the mortality burden of climate change varied greatly by the mortality categories. Further investigations are warranted to comprehensively understand the impacts of climate change on different types of disease across various regions.

Heat related mortality in the two largest Belgian urban areas: A time series analysis

BACKGROUND

Summer temperatures are expected to increase and heat waves will occur more frequently, be longer, and be more intense as a result of global warming. A growing body of evidence indicates that increasing temperature and heatwaves are associated with excess mortality and therefore global heating may become a major public health threat. However, the heat-mortality relationship has been shown to be location-specific and differences could largely be explained by the most frequent temperature. So far, in Belgium there is little known regarding the heat-mortality relationship in the different urban areas.

OBJECTIVES

The objective of this study is to assess the heat-mortality relationship in the two largest urban areas in Belgium, i.e. Antwerp and Brussels for the warm seasons from 2002 until 2011 taking into account the effect of air pollution.

METHODS

The threshold in temperature above which mortality increases was determined using segmented regressions for both urban areas. The relationship between daily temperature and mortality above the threshold was investigated using a generalized estimated equation with Poisson distribution to finally determine the percentage of deaths attributable to the effect of heat.

RESULTS

Although only 50 km apart, the heat-mortality curves for the two urban areas are different. More specifically, an increase in mortality occurs above a maximum temperature of 25.2 °C in Antwerp and 22.8 °C in Brussels. We estimated that above these thresholds, there is an increase in mortality of 4.9% per 1 °C in Antwerp and of 3.1% in Brussels. During the study period, 1.5% of the deaths in Antwerp and 3.5% of the deaths in Brussels can be attributed to the effect of heat. The thresholds differed considerably from the most frequent temperature, particularly in Antwerp. Adjustment for air pollution attenuated the effect of temperature on mortality and this attenuation was more pronounced when adjusting for ambient ozone.

CONCLUSION

Our results show a significant effect of temperature on mortality above a city-specific threshold, both in Antwerp and in Brussels. These findings are important given the ongoing global warming. Recurrent, intense and longer episodes of high temperature and expected changes in air pollutant levels will have an important impact on health in urban areas.

Spatial Variability of Heat-Related Mortality in Barcelona from 1992-2015: A Case Crossover Study Design

Numerous studies have demonstrated the relationship between summer temperatures and increased heat-related deaths. Epidemiological analyses of the health effects of climate exposures usually rely on observations from the nearest weather station to assess exposure-response associations for geographically diverse populations. Urban climate models provide high-resolution spatial data that may potentially improve exposure estimates, but to date, they have not been extensively applied in epidemiological research. We investigated temperature-mortality relationships in the city of Barcelona, and whether estimates vary among districts. We considered georeferenced individual (natural) mortality data during the summer months (June–September) for the period 1992–2015. We extracted daily summer mean temperatures from a 100-m resolution simulation of the urban climate model (UrbClim). Summer hot days (above percentile 70) and reference (below percentile 30) temperatures were compared by using a conditional logistic regression model in a case crossover study design applied to all districts of Barcelona. Relative Risks (RR), and 95% Confidence Intervals (CI), of all-cause (natural) mortality and summer temperature were calculated for several population subgroups (age, sex and education level by districts). Hot days were associated with an increased risk of death (RR = 1.13; 95% CI = 1.10–1.16) and were significant in all population subgroups compared to the non-hot days. The risk ratio was higher among women (RR = 1.16; 95% CI= 1.12–1.21) and the elderly (RR = 1.18; 95% CI = 1.13–1.22). Individuals with primary education had similar risk (RR = 1.13; 95% CI = 1.08–1.18) than those without education (RR = 1.10; 95% CI= 1.05–1.15). Moreover, 6 out of 10 districts showed statistically significant associations, varying the risk ratio between 1.12 (95% CI = 1.03–1.21) in Sants-Montjuïc and 1.25 (95% CI = 1.14–1.38) in Sant Andreu. Findings identified vulnerable districts and suggested new insights to public health policy makers on how to develop district-specific strategies to reduce risks.

Projections of Temperature-Attributable Deaths in Portuguese Metropolitan Areas: A Time-Series Modelling Approach

Climate change is now widely recognised as the greatest global threat over the coming decades. This study aimed to quantify and project the effects of climate change on future temperature-attributable mortality due to circulatory system diseases (CSD) in Lisbon metropolitan area (LMA) and in Porto metropolitan area (PMA). The future time slices of Representative Concentration Pathway (RCP 8.5), mid-term (2046–2065) and long-term (2080–2099) were compared with the reference period (1986–2005). There is a significant decreasing trend in proportion to the overall extreme cold temperature-attributable mortality due to CSD in the future periods (2045–2065 and 2081–2099) in LMA, −0.63% and −0.73%, respectively, and in PMA, −0.62% for 2045–2065 and −0.69% for 2081–2099, compared to the historical period. The fraction attributable to extreme hot temperature in the summer months increased by 0.08% and 0.23%, from 0.04% in the historical period to 0.11% during 2046–2065, and to 0.27% during 2081–2099 in LMA. While there were no noticeable changes due to extreme hot temperature during the summer in PMA, significant increases were observed with warmer winter temperatures: 1.27% and 2.80%. The projections of future temperature-attributable mortality may provide valuable information to support climate policy decision making and temperature-related risk management.

Will there be cold-related mortality in Spain over the 2021-2050 and 2051-2100 time horizons despite the increase in temperatures as a consequence of climate change?

INTRODUCTION

Global warming is resulting in an increase in temperatures which is set to become more marked by the end of the century and depends on the accelerating pace of greenhouse gas emissions into the atmosphere. Yet even in this scenario, so-called "cold waves" will continue to be generated and have an impact on health.

OBJECTIVES

This study sought to analyse the impact of cold waves on daily mortality at a provincial level in Spain over the 2021-2050 and 2051-2100 time horizons under RCP4.5 and RCP 8.5 emission scenarios, on the basis of two hypotheses: (1) that the cold-wave definition temperature (T _threshold) would not vary over time; and, (2) that there would be a variation in T _threshold.

MATERIAL AND METHODS

The results of a retrospective study undertaken for Spain as a whole across the period 2000-2009 enabled us to ascertain the cold-wave definition temperature at a provincial level and its impact on health, measured by reference to population attributable risk (PAR). The minimum daily temperatures projected for each provincial capital considering the above time horizons and emission scenarios were provided by the State Meteorological Agency. On the basis of the T _threshold definition values and minimum daily temperatures projected for each province, we calculated the expected impact of low temperatures on mortality under the above two hypotheses. Keeping the PAR values constant, it was assumed that the mortality rate would vary in accordance with the available data.

RESULTS

If T _threshold remained constant over the above time horizons under both emission scenarios, there would be no cold-related mortality. If T _threshold were assumed to vary over time, however, then cold-related mortality would not disappear: it would instead remain practically constant over time and give rise to an estimated overall figure of around 250 deaths per year, equivalent to close on a quarter of Spain's current annual cold-related mortality and entailing a cost of approximately €1000 million per year.

CONCLUSION

Given that cold waves are not going to disappear and that their impact on mortality is far from negligible and is likely to remain so, public health prevention measures must be implemented to minimise these effects as far as possible.

Heat-health action plans in Europe: Challenges ahead and how to tackle them

High temperatures have periodically affected large areas in Europe and urban settings. In particular, the deadly 2003 summer heat waves precipitated a multitude of national and subnational health prevention and research efforts. Building on these and other international experiences the WHO Regional Office for Europe developed and published in 2008 a comprehensive framework for prevention, the heat-health action plans (HHAPs). This provided a blueprint used by several national and subnational authorities to design their prevention efforts. A decade after the publication of the WHO guidance, a wealth of new evidence and acquired implementation experience has emerged around HHAP effectiveness; heat exposure; acclimatization and adaptation; heat-health governance and stakeholder involvement; and the role of urban design and greening interventions in prevention. This evidence and experience can guide the strategies to tackle current and upcoming challenges in protecting health from heat under a warming climate.

Mortality attributable to high temperatures over the 2021-2050 and 2051-2100 time horizons in Spain: Adaptation and economic estimate

BACKGROUND

In recent years, a number of studies have been conducted with the aim of analysing the impact that high temperatures will have on mortality over different time horizons under different climate scenarios. Very few of these studies take into account the fact that the threshold temperature used to define a heat wave will vary over time, and there are practically none which calculate this threshold temperature for each geographical area on the assumption that there will be variations at a country level.

OBJECTIVE

To analyse the impact that high temperatures will have on mortality across the periods 2021-2050 and 2051-2100 under a high-emission climate scenario (RCP8.5), in a case: (a) where adaptation processes are not taken into account; and (b) where complete adaptation processes are taken into account.

MATERIAL AND METHODS

Based on heat-wave definition temperature (T_threshold) values previously calculated for the reference period, 2000-2009, for each Spanish provincial capital, and their impact on daily mortality as measured by population attributable risk (PAR), the impact of high temperatures on mortality will be calculated for the above-mentioned future periods. Two hypotheses will be considered, namely: (a) that T_threshold does not vary over time (scenario without adaptation to heat); and, (b) that T_threshold does vary over time, with the percentile to which said T_threshold corresponds being assumed to remain constant (complete adaptation to heat). The temperature data were sourced from projections generated by Coupled Model Intercomparison Project (CMIP5) climate models adapted to each region's local characteristics by the State Meteorological Agency (Agencia Estatal de Meteorología/AEMET). Population-growth projections were obtained from the National Statistics Institute (Instituto Nacional de Estadística/INE). In addition, an economic estimate of the resulting impact will be drawn up.

RESULTS

The mean value of maximum daily temperatures will rise, in relation to those of the reference period (2000-2009), by 1.6⁰C across the period 2021-2050 and by 3.3⁰C across the period 2051-2100. In a case where there is no heat-adaptation process, overall annual mortality attributable to high temperatures in Spain would amount to 1414 deaths/year (95% CI: 1089-1771) in the period 2021-2050, rising to 12,896 deaths/year (95% CI: 9852-15,976) in the period 2051-2100. In a case where there is a heat-adaptation process, annual mortality would be 651 deaths/year (95% CI: 500-807) in the period 2021-2050, and 931 deaths per year (95% CI: 770-1081) in the period 2051-2100. These results display a high degree of heterogeneity. The savings between a situation that does envisage and one that does not envisage an adaptive process is €49,100 million/year over the 2051-2100 time horizon.

CONCLUSION

A non-linear increase in maximum daily temperatures was observed, which varies widely from some regions to others, with an increase in mean values for Spain as a whole that is not linear over time. The high degree of heterogeneity found in heat-related mortality by region and the great differences observed on considering an adaptive versus a non-adaptive process render it necessary for adaptation plans to be implemented at a regional level.

Public perceptions of the health risks of extreme heat across US states, counties, and neighborhoods

Extreme heat is the leading weather-related cause of death in the United States. Many individuals, however, fail to perceive this risk, which will be exacerbated by global warming. Given that awareness of one's physical and social vulnerability is a critical precursor to preparedness for extreme weather events, understanding Americans' perceptions of heat risk and their geographic variability is essential for promoting adaptive behaviors during heat waves. Using a large original survey dataset of 9,217 respondents, we create and validate a model of Americans' perceived risk to their health from extreme heat in all 50 US states, 3,142 counties, and 72,429 populated census tracts. States in warm climates (e.g., Texas, Nevada, and Hawaii) have some of the highest heat-risk perceptions, yet states in cooler climates often face greater health risks from heat. Likewise, places with older populations who have increased vulnerability to health effects of heat tend to have lower risk perceptions, putting them at even greater risk since lack of awareness is a barrier to adaptive responses. Poorer neighborhoods and those with larger minority populations generally have higher risk perceptions than wealthier neighborhoods with more white residents, consistent with vulnerability differences across these populations. Comprehensive models of extreme weather risks, exposure, and effects should take individual perceptions, which motivate behavior, into account. Understanding risk perceptions at fine spatial scales can also support targeting of communication and education initiatives to where heat adaptation efforts are most needed.

Time trends in the impact attributable to cold days in Spain: Incidence of local factors

BACKGROUND

While numerous studies have shown that the impact of cold waves is decreasing as result of various processes of adaptation, far fewer have analysed the time trend shown by such impact, and still fewer have done so for the different provinces of a single country, moreover using a specific cold waves definition for each. This study thus aimed to analyse the time trend of the impact of cold days on daily mortality in Spain across the period 1983-2003.

METHODS

For study purposes, we used daily mortality data for all natural causes except accidents in ten Spanish provinces. The time series was divided into three subperiods. For each period and province, the value of T_threshold was obtained via the percentile corresponding to the cold day's definition for that province obtained in previous studies. Relative Risks (RRs) and Population Attributable Fraction (PARs) were calculated using Generalised Linear Models (GLMs) with the Poisson regression link. Seasonalities, trends and autoregressive components were controlled. Global RRs and ARs were calculated with the aid of a meta-analysis with random effects for each of the periods.

RESULTS

The results show that the RRs for Spain as a whole were 1.12 (95% CI: 1.08 1.16) for the first period, 1.15 (95% CI: 1.09 1.22) for the second and 1.18 (95% CI: 1.10 1.26) for the third. The impact of cold days has risen slightly over time, though the differences were not statistically significant. These findings show a clearly different behaviour pattern to that previously found for heat.

CONCLUSION

The results obtained in this study do not show a downward trend for colds days. The complexity of the biological mechanisms involved in cold-related mortality and the lack of robust results mean that more research must be done in this particular field of public health.

Differences in the impact of heat waves according to urban and peri-urban factors in Madrid

Aside from climatic factors, the impact of heat waves on mortality depends on the demographic and socio-economic structure of the population as well as variables relating to local housing. Hence, this study's main aim was to ascertain whether there might be a differential impact of heat waves on daily mortality by area of residence. The study is a time-series analysis (2000-2009) of daily mortality and minimum and maximum daily temperatures (°C) in five geographical areas of the Madrid region. The impact of such waves on heat-related mortality due to natural causes (ICD-10: A00- R99), circulatory causes (ICD-10: I00-I99) and respiratory causes (ICD-10: J00-J99) was obtained by calculating the relative risk (RR) and attributable risk (AR), using GLM models with the Poisson link and controlling for trend, seasonalities and the autoregressive nature of the series. Furthermore, we also evaluated other external variables, such as the percentage of the population aged over 65 years and the percentage of old housing. No heat-related mortality threshold temperature with statistical significance was detected in the northern and eastern areas. While the threshold temperatures in the central and southern areas were very similar and close to the 90th percentile, the threshold in the western area corresponded to the 97th percentile. Attributable mortality proved to be highest in the central area with 85 heat wave-related deaths per annum. External factors found to influence the impact of heat on mortality in Madrid were the size of the population aged over 65 years and the age of residential housing. Demographic structure and the percentage of old housing play a key role in modulating the impact of heat waves. This study concludes that the areas in which heat acts earliest are those having a higher degree of population ageing.

Cold-related mortality vs heat-related mortality in a changing climate: A case study in Vilnius (Lithuania)

INTRODUCTION

Direct health effects of extreme temperatures are a significant environmental health problem in Lithuania, and could worsen further under climate change. This paper attempts to describe the change in environmental temperature conditions that the urban population of Vilnius could experience under climate change, and the effects such change could have on excess heat-related and cold-related mortality in two future periods within the 21st century.

METHODS

We modelled the urban climate of Vilnius for the summer and winter seasons during a sample period (2009-2015) and projected summertime and wintertime daily temperatures for two prospective periods, one in the near (2030-2045) and one in the far future (2085-2100), under the Representative Concentration Pathway (RCP) 8.5. We then analysed the historical relationship between temperature and mortality for the period 2009-2015, and estimated the projected mortality in the near future and far future periods under a changing climate and population, assuming alternatively no acclimatisation and acclimatisation to heat and cold based on a constant-percentile threshold temperature.

RESULTS

During the sample period 2009-2015 in summertime we observed an increase in daily mortality from a maximum daily temperature of 30 °C (the 96th percentile of the series), with an average of around 7 deaths per year. Under a no acclimatisation scenario, annual average heat-related mortality would rise to 24 deaths/year (95% CI: 8.4-38.4) in the near future and to 46 deaths/year (95% CI: 16.4-74.4) in the far future. Under a heat acclimatisation scenario, mortality would not increase significantly in the near or in the far future. Regarding wintertime cold-related mortality in the sample period 2009-2015, we observed increased mortality on days on which the minimum daily temperature fell below - 12 °C (the 7th percentile of the series), with an average of around 10 deaths a year. Keeping the threshold temperature constant, annual average cold-related mortality would decrease markedly in the near future, to 5 deaths/year (95% CI: 0.8-7.9) and even more in the far future, down to 0.44 deaths/year (95% C: 0.1-0.8). Assuming a "middle ground" between the acclimatisation and non-acclimatisation scenarios, the decrease in cold-related mortality will not compensate the increase in heat-related mortality.

CONCLUSION

Thermal extremes, both heat and cold, constitute a serious public health threat in Vilnius, and in a changing climate the decrease in mortality attributable to cold will not compensate for the increase in mortality attributable to heat. Study results reinforce the notion that public health prevention against thermal extremes should be designed as a dynamic, adaptive process from the inception.

Сardiovascular mortality during heat waves in temperate climate: an association with bioclimatic indices

The authors studied the relative predictive powers of several bioclimatic indices as predictors of population mortality during heat waves. Daily mean and maximum values of air temperature, Humidex, apparent, and physiological equivalent temperatures (PETs) were examined. The numbers of daily deaths and daily meteorological data in Rostov-on-Don (southern Russia) were used. The study period spanned April-September between 1999 and 2011. The eight selected bioclimatic indices were used to identify heat waves and calculate the expected increases in mortality during such events from Poisson generalized linear model of daily death counts. All of the bioclimatic indices considered were positively and significantly associated with mortality during heat waves. The best predictor was chosen from a set of similar models by maximization of relative mortality risk estimates. Having compared the relative increases and their significance levels in several cause- and age-specific mortality rates, the authors concluded that PET was the most powerful predictor.

Time trend in the impact of heat waves on daily mortality in Spain for a period of over thirty years (1983-2013)

Many of the studies that analyze the future impact of climate change on mortality assume that the temperature that constitutes a heat wave will not change over time. This is unlikely, however, given the process of adapting to heat changes, prevention plans, and improvements in social and health infrastructure. The objective of this study is to analyze whether, during the 1983-2013 period, there has been a temporal change in the maximum daily temperatures that constitute a heat wave (T_threshold) in Spain, and to investigate whether there has been variation in the attributable risk (AR) associated with mortality due to high temperatures in this period. This study uses daily mortality data for natural causes except accidents CIEX: A00-R99 in municipalities of over 10,000 inhabitants in 10 Spanish provinces and maximum temperature data from observatories located in province capitals. The time series is divided into three periods: 1983-1992, 1993-2003 and 2004-2013. For each period and each province, the value of T_threshold was calculated using scatter-plot diagram of the daily mortality pre-whitened series. For each period and each province capitals, it has been calculated the number of heat waves and quantifying the impact on mortality through generalized linear model (GLM) methodology with the Poisson regression link. These models permits obtained the relative risks (RR) and attributable risks (AR). Via a meta-analysis, using the Global RR and AR were calculated the heat impact for the total of the 10 provinces. The results show that in the first two periods RR remained constant RR: 1.14 (CI95%: 1.09 1.19) and RR: 1.14 (CI95%: 1.10 1.18), while the third period shows a sharp decrease with respect to the prior two periods RR: 1.01 (CI95%: 1.00 1.01); the difference is statistically significant. In Spain there has been a sharp decrease in mortality attributable to heat over the past 10 years. The observed variation in RR puts into question the results of numerous studies that analyze the future impact of heat on mortality in different temporal scenarios and show it to be constant over time.