Impact Of Heat Waves Research Articles

How was the impact of heatwaves on daily hospital admissions in Portugal (2000-2018)?

Abstract Background Climate change has increased the frequency, intensity, and duration of heatwaves, posing a serious threat to public health. While the link between high temperatures and premature mortality has been extensively studied, the comprehensive quantification of heatwave impacts on morbidity remains understudied. Methods We assessed the relationship between heatwaves and daily hospital admissions at a county level in Portugal, considering all major diagnostic categories and age groups, over a 19-year period from 2000 to 2018. Our nationwide study included a comprehensive geospatial analysis, integrating over 12 million hospital admission records with heatwave events indexed by the Excess Heat Factor (EHF), covering all 278 mainland counties. To estimate the impact of heatwaves on hospital admissions, we applied negative binomial regression models at both national and county levels. Results A statistically significant overall 18·9% increase in daily hospital admissions was found during heatwave days (IRR=1·189, 95% CI: 1·179-1·198). This impact affected all age groups, with pediatric ages being the most affected (21·7%), followed by the working-age (19·7%) and elderly individuals (17·2%). All 25 Major Disease Diagnostic Categories experienced significant increases, particularly Burns (34·3%), Multiple Significant Trauma (26·8%), and Infectious and Parasitic Diseases (25·4%). Notable rises were also observed in Endocrine, Nutritional, and Metabolic (25·1%), Mental (23%), Respiratory (22·4%), and Circulatory (15·8%) diseases. Conclusions Our results provide statistically significant evidence of the association between heatwaves and increased hospitalizations across all age groups and for all major causes of disease. This is the first study to estimate the full extent of heatwaves’ impact on hospitalizations using the EHF index over a comprehensive 19-year period, encompassing an entire country, and spanning 25 disease categories during multiple heatwave events. Key messages • There is a clear association between heatwaves and increased hospital admissions across all age groups and Major Diagnostic Categories. • Our data offer crucial information to guide policymakers in effectively and efficiently allocating resources to address the profound healthcare consequences resulting from climate change.

Sex differences in mortality associated with heatwaves: a systematic review and meta-analysis

Abstract Introduction The existence of sex and gender differences in the mortality associated with heatwaves remains unclear. Methods A systematic review and random-effects meta-analysis of population-based studies that investigated the mortality associated with heatwaves and reported results stratified by sex/gender was conducted (PROSPERO registration CRD42023430208). Bibliographic databases Medline and Embase were searched from inception to May 2024 with MESH terms for heatwaves/extreme heat and mortality. This was complemented with hand-searching of reference lists of relevant studies. The methodological quality of eligible studies was assessed using the Joanna Briggs Institute critical appraisal tool. Results In total, 931 studies were identified, of which 32 studies were included in the qualitative review and 11 in the meta-analysis. Most studies (20/32) reported a higher risk of heat-related death for women than men even after adjusting for or stratifying by age. Twelve studies showed statistically significant higher risks of death for women than men and 7 studies identified an increased risk of death for women, but the wide confidence intervals precluded making definite conclusions. Two studies reported a higher risk of death for men in comparison to women but only one was statistically significant. The remaining 10 studies found comparable risks for women and men. For the 11 studies included in the meta-analysis, women had an 8% increased risk of death in comparison to men (RR 1.08, 95% CI [1.02 to 1.14]). There was significant heterogeneity (I2=69%, p = 0.001) due to the variability in the definition of exposure, population, and setting. Most studies had a low to moderate risk of bias. Conclusions Women appeared to have an increased risk of death associated with heatwaves in comparison to men. Further research is warranted to understand the underlying factors and ensure the health protection response considers the gendered impact of heatwaves.

The combined effects of heatwaves, air pollution and greenery on the risk of frailty: a national cohort study

The associations between heatwaves and frailty, as well as the joint effects of heatwaves with air pollution and greenery, are currently unknown. This study leverages data from the China Health and Retirement Longitudinal Study (CHARLS), which collected information from 6,400 older adults between 2011 and 2018. Our outcome variable was frailty, as measured by the frailty index (FI > 0.21). Heatwaves were defined based on maximum temperature, incorporating four thresholds (≥ 97.5%, 97.5%, 92.5%, and 90%) and three durations (≥ 2, 3, and 4 days). These variables were considered as time-varying variables, representing the one-year exposure preceding survival events. Fine particulate matter (PM2.5) and greenery (normalized difference vegetation index (NDVI)) were utilized as indicators of air pollution and greenery exposure, respectively, and were treated as time-varying indicators concurrent with heatwaves.Time-varying Cox proportional hazards models were employed to assess the independent effects, as well as the multiplicative and additive interactions of heatwaves, air pollution, and greenery on the risk of frailty. These effects were quantified using hazard ratios (HRs), a traditional product term representing the ratio of HRs, and the relative excess risk due to interaction (RERI). Our findings indicate that heatwaves are associated with an increased risk of frailty, with HRs ranging from 1.035 (95% CI: 1.006–1.064) to 1.063 (95% CI: 1.028–1.101). We observed both a positive multiplicative interaction (HRs > 1) and an additive interaction (RERI > 0) between high level PM2.5 concentration, lack of greenery, and heatwaves. This study reveals that the combined effects exacerbate the adverse impact of heatwaves on the risk of frailty. Moreover, the combined effects of heatwaves, air pollution, and greenery exposure on frailty risk vary across age, gender, and educational attainment.

Compound and cascading droughts and heatwaves decrease maize yields by nearly half in Sinaloa, Mexico

The impact of droughts and heatwaves on agriculture losses has been exacerbated by the occurrence of compound and cascading events. Here we present a study that evaluates the impact of these events both as singly and as compound and cascading on maize yield in Sinaloa Mexico from 1990 to 2022, using the WOFOST crop model. Drought and heatwave events were identified using the Standardized Precipitation Index and threshold method, respectively. Results show that yield reduction (25%) is found during extreme drought events, emphasizing the vulnerability of maize farming to unfavorable drought conditions. While heatwaves alone did not show a significant impact on maize yields, the compound and cascading droughts and heatwaves amplified the loss of maize yields by up to 44% compared to normal conditions. This study highlights the need for adaptive strategies in agriculture to sustain food security during extreme events, especially in the context of multi hazard framework.

Clinical Spectrum of Heatstroke in a Tertiary Care Hospital during the 2024 Delhi Heat wave Peak

Abstract Background: Heat-related illnesses (HRIs) have a wide spectrum from relatively mild heat cramps to heatstroke in its severest form. The 2024 heat wave in Delhi, with temperatures consistently above 40°C, resulted in over 270 deaths due to heatstroke. This study examines nine cases of classical heatstroke admitted over a 24-h period to a tertiary care hospital in Delhi. Materials and Methods: This is a cross-sectional study of patients presenting to emergency with altered consciousness during the 24-h period just before the culmination of the 40-day long heat wave period. In the absence of alternative etiologies on the investigation, a diagnosis of classical heatstroke was entertained. The sociodemographic details, clinical features, investigations, treatment, and outcomes of nine such patients are being reported. Results: Common symptoms observed in the patients were hyperthermia (100%), dehydration (100%), altered sensorium (100%), vomiting (33%), and seizures (33%). Laboratory findings showed respiratory alkalosis (100%), hypokalemia (88.8%), thrombocytopenia (88.8%), and transaminitis (77.7%). Eight heatstroke patients required mechanical ventilation. Despite intensive treatment, three patients died, whereas six were discharged in stable condition. Conclusion: The 2024 heat wave in Delhi highlighted the severe impact of extreme heat on health. The spectrum of clinical features in classical heatstroke has been outlined. The impact of heat wave was such that even normal individuals accustomed to high-heat environments developed HRI. Early recognition and rapid cooling are crucial in managing heatstroke. Improved public awareness, healthcare infrastructure, and management protocols are essential to mitigate the effects of future heat waves.

Prediction of heatwave related mortality magnitude, duration and frequency with climate variability and climate change information

Given the link between climatic factors on one hand, such as climate change and low frequency climate oscillation indices, and the occurrence and magnitude of heat waves on the other hand, and given the impact of heat waves on mortality, these climatic factors could provide some predictive skill for mortality. We propose a new model, the Mortality-Duration-Frequency (MDF) relationship, to relate the intensity of an extreme summer mortality event to its duration and frequency. The MDF model takes into account the non-stationarities observed in the mortality data through covariates by integrating information concerning climate change through the time trend and climate variability through climate oscillation indices. The proposed approach was applied to all-cause mortality data from 1983 to 2018 in the metropolitan regions of Quebec and Montreal in eastern Canada. In all cases, models introducing covariates lead to a substantial improvement in the goodness-of-fit in comparison to stationary models without covariates. Climate change signal is more important than climate variability signal in explaining maximum summer mortality. However, climate indices successfully explain a part of the interannual variability in the maximum summer mortality. Overall, the best models are obtained with the time trend and the North Atlantic Oscillation (NAO) used as covariates. No country has yet integrated teleconnection information in their heat-health watch and warning systems or adaptation plans. MDF modeling has the potential to be useful to public health managers for the planning and management of health services. It allows predicting future MDF curves for adaptive management using the values of the covariates.

Implementation of a Temperature Monitoring and Measurement Network in the Urban Context: A Case Study of Kasba Tadla, Morocco, 2022.

Abstract In the context of climate change, this study focuses on the impact of heatwaves, which have become the dominant meteorological phenomenon in terms of duration and intensity. The objective is to understand the temporal variation of temperatures in the urban domain, highlighting thermal differences on an hourly scale. The city of Kasba Tadla, located in the Tadla plain in Morocco, is at the core of this research. This rapidly expanding urban area is traversed by the Oum Er-rbia River. The selection of this region allows for a specific analysis of the climate challenges a rapidly growing city may face. The methodology relies on a network of four fixed meteorological stations installed in the city of Kasba Tadla. Temperature measurements were taken on an hourly timescale during the summer of 2022. This approach enables a detailed analysis of temperature variation based on building density and the presence of vegetation in different neighborhoods. The results highlight a significant temperature variation within the city, emphasizing the impact of building density and vegetation on this phenomenon.

Understanding excess mortality in 2022: The dual impact of COVID-19 and heatwaves on the Italian elderly population

In this study, we employ a comprehensive approach to model the concurrent effects of the COVID-19 epidemic and heatwaves on all-cause excess mortality. Our investigation uncovers distinct peaks in excess mortality, notably among individuals aged 80 years and older, revealing a strong positive correlation with excess temperatures (ET) during the summer of 2022 in Italy. Furthermore, we identify a notable role played by COVID-19 hospitalizations, exhibiting regional disparities, particularly during the winter months. Leveraging functional data regression, we offer robust and coherent insights into the excess mortality trends observed in Italy throughout 2022.

Heatwaves and its impact on the depressive symptoms among Chinese community-dwelling older adults: examining the role of social participation

ObjectivesBased on the Environment-Person Fit Perspective, this study explores the relationship between heatwaves and subsequent depressive symptoms among older Chinese community dwellers. Additionally, the study investigates if this association varies among older adults with different levels of social participation. MethodsHeatwaves were defined as the frequency of occurrences where daily maximum temperature exceeded 35°C for 3 consecutive days. A sample including 7124 older adults aged 55 and above was selected from the 2018 China Health and Retirement Longitudinal Study. Depressive symptoms were measured by the 10-item Centre for Epidemiological Studies Depression Scale. Social participation was measured by volunteer participation and leisure participation. Multilevel fixed effect model was employed to investigate the temporal association between heatwaves and depressive symptoms, as well as the moderating effect of social participation. ResultsThis study found that older adults who had experienced a greater number of heatwaves presented more severe depressive symptoms (b = 0.66, p < 0.001). However, a high level of leisure participation buffered the effect of heatwaves on depressive symptoms (b = ̶ 0.52, p < 0.05). ConclusionsThis study highlighted the differential impact of heatwaves on mental health outcomes among older adults depending on their levels of social participation. Our findings provide valuable insights into designing an integrative heatwave adaption scheme that simultaneously focuses on temperature adjustment and social participation enhancement.

Association Between Extreme Heat and Outpatient Visits for Mental Disorders: A Time-Series Analysis in Guangzhou, China.

Previous evidence on heatwaves' impact on mental health outpatient visits is limited, especially uncertainty on how different heatwave definitions affect this relationship. In this time-series study, we assessed the association between heatwaves and outpatient visits for mental disorders in Guangzhou, China. Daily outpatient visits for mental disorders and its specific categories (schizophrenia, mood, and neurotic disorders) were sourced from the Urban Resident-based Basic Medical Insurance (URBMI) and the Urban Employee-based Basic Medical Insurance (UEBMI) claims databases in Guangzhou from 2010 to 2014. The study employed nine heatwave definitions, based on combinations of three daily mean temperature thresholds (90th, 92.5th, and 95th percentiles) and durations (2, 3, and 4days). Using quasi-Poisson generalized linear models (GLMs), we estimated the risks (at lag 0day) and cumulative effects (lag 0-10days) of heatwaves on mental disorder outpatient visits. Age, gender, types of medical insurance were considered as potential effect modifiers. We observed a positive association between heatwaves and increased total outpatient visits for mental disorders, both at lag 0day and during lag 0-10days. The impact of heatwave was significant at lag 0day for schizophrenia, mood and neurotic disorders visits, it remained significant for neurotic and mood disorders visits during lag 0-10days. Heatwave durations lasting more than 4days were associated with higher relative risks of mental disorders at lag 0day. Older adults had relatively higher effect estimations than younger individuals. This research highlights the effects of extreme heat on mental health.

The heat is on: impact of heat waves on critical thermal maxima in larvae and adults of solitary bee Osmia bicornis (Hymenoptera: Megachilidae)

Extreme temperature events, such as heat waves, are increasing in frequency, magnitude, and duration. These events are believed to contribute to pollinator decline. Critical thermal maxima (CTmax) is a key physiological trait for understanding an organism’s ecology and predicting its responses to changes in climate. In this study, we investigated whether different life stages with distinct thermoregulatory behaviors differ in their CTmax in the solitary bee Osmia bicornis, one of the most common and important pollinators in Central Europe. Additionally, we tested the influence of excessively high temperatures, heat waves, on the CTmax in Osmia bicornis. We found CTmax varied among life stages, with adults exhibiting higher CTmax than larvae. Both females and males of adult bees showed a negative correlation between CTmax and body mass. Interestingly, adult bees exposed to different heat waves during their larval stage did not exhibit significant shifts in CTmax. These results suggest that bees may have limited capacity to enhance heat tolerance in response to prior heat exposure.

Increasing exposure of global croplands productivity to growing season heatwaves under climate warming

Abstract Growing season heatwaves that occur simultaneously over global croplands can negatively impact global food baskets. The long-term changes of growing season heatwaves, as well as their impacts on croplands productivity, are crucial to food security, but remain unclear. Here, we investigated changes in the frequency, intensity and magnitude of growing season heatwaves from the past to the future over the global croplands, based on observations and Coupled Model Intercomparison Project Phase 6 models. We introduced an index, gross primary productivity (GPP) exposure, as a proxy of the overall impact of heatwaves on cropland productivity. The results show that the frequency and intensity of growing season heatwaves have increased since 1950 and will continue throughout the 21st century. The increase of the annual accumulated magnitude of growing season heatwaves in the future is mainly contributed by the increase of heatwave frequency. This leads to a global-scale increase in the GPP exposure to growing season heatwaves, with Asia, North America, and Europe being the most affected. The continued increase in GPP exposure is dominated by increases in heatwaves rather than GPP itself. Under the lower emission scenario SSP1-2.6, the global cropland GPP exposure will reduce by 86.11% and 330.47% relative to that under SSP2-4.5 and SSP5-8.5 scenarios, respectively, by the end of 21st century. Our results provide crucial insights into potential impacts of heatwaves on cropland productivity and hence food security.

The influence of temperature and genomic variation on intracranial EEG measures in people with epilepsy.

Heatwaves have serious impacts on human health and constitute a key health concern from anthropogenic climate change. People have different individual tolerance for heatwaves or unaccustomed temperatures. Those with epilepsy may be particularly affected by temperature as the electroclinical hallmarks of brain excitability in epilepsy (inter-ictal epileptiform discharges and seizures) are influenced by a range of physiological and non-physiological conditions. Heatwaves are becoming more common and may affect brain excitability. Leveraging spontaneous heatwaves during periods of intracranial EEG recording in participants with epilepsy in a non-air-conditioned telemetry unit at the National Hospital for Neurology and Neurosurgery in London from May to August 2015-22, we examined the impact of heatwaves on brain excitability. In London, a heatwave is defined as three or more consecutive days with daily maximum temperatures ≥28°C. For each participant, we counted inter-ictal epileptiform discharges using four 10-min segments within, and outside of, heatwaves during periods of intracranial EEG recording. Additionally, we counted all clinical and subclinical seizures within, and outside of, heatwaves. We searched for causal rare genetic variants and calculated the epilepsy PRS. Nine participants were included in the study (six men, three women), median age 30 years (range 24-39). During heatwaves, there was a significant increase in the number of inter-ictal epileptiform discharges in three participants. Five participants had more seizures during the heatwave period, and as a group, there were significantly more seizures during the heatwaves. Genetic data, available for eight participants, showed none had known rare, genetically-determined epilepsies, whilst all had high polygenic risk scores for epilepsy. For some people with epilepsy, and not just those with known, rare, temperature-sensitive epilepsies, there is an association between heatwaves and increased brain excitability. These preliminary data require further validation and exploration, as they raise concerns about the impact of heatwaves directly on brain health.

Tropical and mid-latitude causal drivers of the eastern Mediterranean Etesians during boreal summer

During boreal summer, large scale subsidence and a persistent northerly flow, known as the Etesians, characterize the tropospheric circulation over the eastern Mediterranean. The Etesians bring clear skies and alleviate the impact of heat waves over the region. The intraseasonal variability of the Etesians and subsidence over the eastern Mediterranean has been thought to be influenced by the South Asian monsoon and atmospheric processes over the North Atlantic. Here, we employ causal effect networks and causal maps, obtained by applying the Peter and Clark Momentary Conditional Independence (PCMCI) causal discovery algorithm, to identify causal precursors of Etesians. We find that both wave train activity over the North Atlantic/North American region and convective activity over South Asia associated with the Indian summer monsoon (ISM) are causally related to the Etesians at 3-day time scale. Thus, intraseasonal ISM variability affects the eastern Mediterranean circulation, though its influence is conveyed via a Middle East ridge. On longer weekly time scale, the mid-latitude influence weakens, while the influence of the tropical convective activity via the Middle East ridge remains stable. Moreover, the heat low over the Arabian Peninsula, a feature strongly responsible for the development of the Etesians, is caused by a stronger Middle East ridge and not by North Atlantic wave activity. Finally, we discuss potential implication for circulation changes in the eastern Mediterranean due to anthropogenic global warming.

Impact of Heatwaves and Declining NOx on Nocturnal Monoterpene Oxidation in the Urban Southeastern United States.

Nighttime oxidation of monoterpenes (MT) via the nitrate radical (NO3) and ozone (O3) contributes to the formation of secondary organic aerosol (SOA). This study uses observations in Atlanta, Georgia from 2011-2022 to quantify trends in nighttime production of NO3 (PNO3) and O3 concentrations and compare to model outputs from the EPA's Air QUAlity TimE Series Project (EQUATES). We present urban-suburban gradients in nighttime NO3 and O3 concentrations and quantify their fractional importance (F) for MT oxidation. Both observations and EQUATES show a decline in PNO3, with modeled PNO3 declining faster than observations. Despite decreasing PNO3, we find that NO3 continues to dominate nocturnal boundary layer (NBL) MT oxidation (FNO3 = 60%) in 2017, 2021, and 2022, which is consistent with EQUATES (FNO3 = 80%) from 2013-2019. This contrasts an anticipated decline in FNO3 based on prior observations in the nighttime residual layer, where O3 is the dominant oxidant. Using two case studies of heatwaves in summer 2022, we show that extreme heat events can increase NO3 concentrations and FNO3, leading to short MT lifetimes (<1 h) and high gas-phase organic nitrate production. Regardless of the presence of heatwaves, our findings suggest sustained organic nitrate aerosol formation in the urban SE US under declining NOx emissions, and highlight the need for improved representation of extreme heat events in chemistry-transport models and additional observations along urban to rural gradients.

Powering up in a warming world: the impacts of heat waves on power generation in China

ABSTRACT This paper investigates the impact of heat waves on China’s electricity generation by integrating micro-level data on power plants with meteorological data from 2007 to 2016. Our results show that an additional day with an average daily temperature between 25°C and 30°C, and above 30°C, compared to temperatures between 10°C and 15°C, leads to a 0.4% and 0.7% increase in power generation, respectively. These effects are particularly pronounced in thermal power and hydropower plants, as opposed to those utilizing renewable energy sources, thereby exacerbating environmental degradation. Notably, an additional day with temperatures exceeding 30°C would result in an increase of approximately 24 million tons in carbon dioxide emissions from thermal power alone. We further identify that power plants located in the central region, those with larger capacities, and state-owned power plants are more acutely affected by high temperatures. Based on the regression results and future temperature forecasts, we project that China’s electricity generation will increase by 2.4% to 9.6%, 5.7% to 23.1%, and 4.4% to 35.6% in the short, medium, and long term, respectively, depending on whether greenhouse gas emissions are controlled. Our findings suggest that China’s energy policy should prioritize the low-carbon transformation of the power supply structure.

Evaluation of physiological and thermal comfort effectiveness of ceiling fan and table fan during a heat wave

Heat waves are becoming a significant global concern as they have substantial repercussions on human health. Further, the adverse impact of heat waves on health will likely worsen globally. The use of electric fans is an energy-saving and sustainable cooling strategy against heat waves, but current health guidelines discourage fan use during heat waves. Previous research has shown that health guidelines underestimated the evaporative cooling impact of fans. These studies mainly focused on the effects of table fans on various physiological parameters of occupants in hot environments. Nevertheless, the air movement produced by both table fans and ceiling fans may influence the occupants’ physiological and perceptual responses significantly. Hence, the present study investigated the effectiveness of no-fan, table-fan and ceiling-fan conditions during heat waves through an experimental approach. Sixteen healthy young participants were exposed to an air temperature of 41.0 ± 0.5 °C and relative humidity of 35 ± 2 % for 2 hours. The participants’ physiological parameters and perceptual responses were collected. We found that both table and ceiling fans delay the changes in thermoregulatory and cardiovascular strain compared to the no-fan scenario. Moreover, table fans minimize physiological strain and provide greater comfort than ceiling fans. Hence, people should opt for table fans over ceiling fans during heat waves.

Metallic Coatings Boost the Cooling Power of Nanoporous Alumina.

Passive daytime radiative cooling (PDRC) has emerged as a promising strategy to mitigate the increasing impact of heat waves. However, achieving effective PDRCs requires cost-effective, ecofriendly, and industrially scalable materials. In this study, we investigate the potential of anodic aluminum oxide (AAO) nanostructures coated with metals as passive radiative coolers. We explore the effects of different metallic coatings (Al and Au) with varying thicknesses (ranging from 20 to 100 nm) on the cooling performance of the AAO nanostructures. Our finding reveals a maximum temperature reduction (ΔT) of 12.5 °C for 60 nm of Au coating. Furthermore, we demonstrate the dependence of the cooling performance on ambient temperature, emphasizing the practical benefits of these enhanced AAO-based radiative coolers for real-world applications. Notably, our results surpass previous works, offering an avenue to enhance the PDRC capability.

Influences on North‐Atlantic summer climate from the El Niño‐Southern Oscillation

AbstractSeasonal‐range predictability of summer climate in northwestern Europe is generally considered to be low. This is an increasing issue given the worsening impact of summer heatwaves, droughts and intense convective rainfall in a rapidly changing climate. In wintertime, predictive skill in the region is derived from a variety of sources, not least teleconnections with the El Niño‐Southern Oscillation (ENSO). Summer ENSO teleconnections, however, are often considered to be negligible. In this paper, we revisit the topic of summer teleconnections between ENSO and the North Atlantic‐European region. We build on previous work identifying upper tropospheric responses to tropical forcing, since dynamical teleconnections are most apparent at this level. Our results confirm that significantly increased geopotential heights are found stretching over the North‐Atlantic region and into western Europe when La Niña conditions are prevalent during summer. This pattern is part of the previously identified ‘circumglobal’ pattern of wider northern‐hemisphere height changes. We then look for these responses in a range of climate models used in operational seasonal prediction. While parts of the circumglobal pattern are weakly present, none of them produce the response seen over the North Atlantic, even when the effect of sampling on the observed teleconnection is accounted for. We additionally estimate the contribution of the previous (wintertime) phase of ENSO on the following summer. We find a significant delayed response, particularly in heights, to the earlier phase. The combination of the delayed and current responses gives height anomalies that are larger, on average, when ENSO changes phase from winter to summer. Finally, we show that a modest level of regional prediction skill from ENSO does exist. There is a contribution to skill in heights from the previous ENSO phase, but the equivalent contribution to the skill of zonal winds is smaller.

Geographical Patterns in Mortality Impacts Due To Heatwaves of Different Characteristics in Spanish Cities.

The impact of heatwaves (HWs) on human health is a topic of growing interest due to the global magnification of these phenomena and their substantial socio-economic impacts. As for other countries of Southern Europe, Spain is a region highly affected by heat and its increase under climate change. This is observed in the mean values and the increasing incidence of extreme weather events and associated mortality. Despite the vast knowledge on this topic, it remains unclear whether specific types and characteristics of HW are particularly harmful to the population and whether this shows a regional interdependency. The present study provides a comprehensive analysis of the relationship between HW characteristics and mortality in 12 Spanish cities. We used separated time series analysis in each city applying a quasi-Poisson regression model and distributed lag linear and non-linear models. Results show an increase in the mortality risk under HW conditions in the cities with a lower HW frequency. However, this increase exhibits remarkable differences across the cities under study not showing any general pattern in the HW characteristics-mortality association. This relationship is shown to be complex and strongly dependent on the local properties of each city pointing out the crucial need to examine and understand on a local scale the HW characteristics and the HW-mortality relationship for an efficient design and implementation of prevention measures.