Effects Of Heat Waves Research Articles

Combined effect of marine heatwaves and light intensity on the cellular stress response and photophysiology of the leather coral Sarcophyton cf. glaucum

Marine heatwaves (MHW) are threatening tropical coral reef ecosystems, leading to mass bleaching events worldwide. The combination of heat stress with high irradiance is known to shape the health and redox status of corals, but research is biased toward scleractinian corals, while much less is known on tropical symbiotic soft corals. Here, we evaluated the cellular stress response and the photophysiological performance of the soft coral Sarcophyton cf. glaucum, popularly termed as leather coral, under different global change scenarios. Corals were exposed to different light intensities (high light, low light, ∼662 and 253 μmol photons m−2 s−1) for 30 days (time-point 1) and a subsequent MHW simulation was carried out for 10 days (control 26 vs 32 °C) (time-point 2). Subsequently, corals were returned to control temperature and allowed to recover for 30 days (time-point 3). Photophysiological performance (maximum quantum yield of photosystem II (Fv/Fm), a measure of photosynthetic activity; dark-level fluorescence (F0), as a proxy of chlorophyll a content (Chl a); and zooxanthellae density) and stress biomarkers (total protein, antioxidants, lipid peroxidation, ubiquitin, and heat shock protein 70) were assessed in corals at these three time-points. Corals were especially sensitive to the combination of heat and high light stress, experiencing a decrease in their photosynthetic efficiency under these conditions. Heat stress resulted in bleaching via zooxanthellae loss while high light stress led to pigment (Chl a) loss. This species' antioxidant defenses, and protein degradation were particularly enhanced under heat stress. A recovery was clear for molecular parameters after 30 days of recovery, whereby photophysiological performance required more time to return to basal levels. We conclude that soft corals distributed along intertidal areas, where the light intensity is high, could be especially vulnerable to marine heatwave events, highlighting the need to direct conservation efforts toward these organisms.

Hot weather hazard analysis over India

Heat waves are often termed as the silent killer and have become even more important as recent studies suggest that the heat wave have become second most devastating extreme weather events in terms of human deaths and losses. It is also been largely realised by scientific community that it is not just the high temperatures which are responsible for the gruesome effect of heat waves but several other meteorological parameters play a vital role in aggravating the impact and causing much more damages. In view of the above the attention of scientific community, weather forecasters as well as disaster managers has shifted to also take into account the different meteorological parameters like maximum and minimum temperatures, relative humidity, wind speed, duration/spell of heat waves and its intensity which are aggravating the impact of heat stress. In this background, this study is undertaken as an attempt to quantify the effect of different meteorological parameters on heat wave on different regions of India for different summer months (March, April, May and June). In this study the impact of individual meteorological parameter as well their cumulative effect is studied based on data of 30 years (1981–2010) for 300 stations. The effect of different meteorological parameters is identified for different months for different regions of the country. Also the cumulative scores are calculated for different regions considering different meteorological parameters, as a first initiative to perform heat hazard analysis and zonation over the entire country. This could serve as initial step for planning mitigation and adaptation strategies throughout the country. These scores as thresholds for different regions may be also useful for operational forecaster’s for early impact based warning services as well as for the disaster managers, for taking effective and timely actions.

Marine heatwaves of differing intensities lead to distinct patterns in seafloor functioning.

Marine heatwaves (MHWs) are increasing in frequency and intensity due to climate change. Several well-documented effects of heatwaves on community structure exist, but examples of their effect on functioning of species, communities or ecosystems remain scarce. We tested the effects of short-term, moderate and strong MHWs on macrofauna bioturbation and associated solute fluxes as examples of ecosystem functioning. We also measured macrofaunal excretion rates to assess effects of temperature on macrofauna metabolism. For this experiment, we used unmanipulated sediment cores with natural animal communities collected from a muddy location at 32 m depth in the northern Baltic Sea. Despite the mechanistic effect of bioturbation remaining unchanged between the treatments, there were significant differences in oxygen consumption, solute fluxes and excretion. Biogeochemical and biological processes were boosted by the moderate heatwave, whereas biogeochemical cycling seemed to decrease under a strong heatwave. A prolonged, moderate heatwave could possibly lead to resource depletion if primary production cannot meet the demands of benthic consumption. By contrast, decreased degradation activities under strong heatwaves could lead to a build-up of organic material and potentially hypoxia. The strong variability and the complexity of the response highlight the context dependency of these processes complicating future predictions.

Urban-rural disparity in heatwave effects on diabetes mortality in eastern China: A case-crossover analysis in 2016–2019

Diabetics are sensitive to high ambient temperature due to impaired thermoregulation. However, available evidence on the impact of prolonged high temperature (i.e., heatwave) on diabetes deaths is limited and whether urban and rural areas differ in heatwave vulnerability remains unknown so far. A time-stratified case-crossover analysis was employed to estimate the association between heatwaves and diabetes deaths in 1486 districts (509 urban and 977 rural areas) of eastern China (Jiangsu Province), 2016–2019. For each decedent, residential heatwave exposure was measured by matching daily mean temperatures to the geocoded residential address. We adopted nine-tiered heatwave definitions incorporating intensity and duration. Stratified analyses by decedents' characteristics (gender, age, and education) were also conducted. During the study period, there were 18,685 deaths from diabetes (urban proportion: 36.95 %, p-value for urban-rural difference < 0.05). Heatwaves were associated with an increased risk of diabetes deaths, with greater and longer-lasting effects in rural areas than urban areas [e.g., rural odds ratio (OR): 1.19 (95 % confidence interval (CI): 1.14, 1.25) vs. urban OR: 1.09 (95 % CI: 1.05, 1.12)]. Risk of diabetes deaths increased with the intensity of heatwaves in rural areas (p-value for trend <0.01), but not in urban areas. Stratified analyses in rural areas suggested that females and less-educated people were more vulnerable to heatwave-related diabetes deaths. Our findings revealed the urban-rural disparity in the risk of diabetes deaths associated with heatwaves. Rural diabetics should be made aware of the increased death risk posed by heatwaves in the context of warming climate.

Association between Land Surface Temperature and Green Volume in Bochum, Germany

Average temperatures continue to rise throughout the world due to climate change and, thus, also in Europe, often occurring as heat waves. The negative effects of climate change-related heat waves can be observed, especially in urban areas where land sealing is the greatest and so is population density. Past studies have indicated that green volume can provide climate improvement by balancing humidity and regulating temperature. This study aims to estimate the distribution of surface heat islands and green volume and test the relationship between these variables in a case study of Bochum, Germany. A method to develop a temporally longitudinal 30-m Landsat 8-based land surface temperature (LST) analysis and 30-m LiDAR-based green volume dataset are presented, and their relationship is tested using Pearson’s correlation (n = 148,204). The results show that heat islands are moderately negatively correlated with green volume (r = −0.482; p &lt; 0.05), LST can vary as much as 28 degrees °C between heat islands and densely vegetated areas, and the distribution is heterogeneous across Bochum.

Nexus of heat-vulnerable chronic diseases and heatwave mediated through tri-environmental interactions: A nationwide fine-grained study in Australia

The warming trend over recent decades has already contributed to the increased prevalence of heat-vulnerable chronic diseases in many regions of the world. However, understanding the relationship between heat-vulnerable chronic diseases and heatwaves remains incomplete due to the complexity of such a relationship mingling with human society, urban and natural environments. Our study extends the Social Ecological Theory by constructing a tri-environmental conceptual framework (i.e., across social, built, and natural environments) and contributes to the first nationwide study of the relationship between heat-vulnerable chronic diseases and heatwaves in Australia. We utilize the random forest regression model to explore the importance of heatwaves and 48 tri-environmental variables that contribute to the prevalence of six types of heat-vulnerable diseases. We further apply the local interpretable model-agnostic explanations and the accumulated local effects analysis to interpret how the heat-disease nexus is mediated through tri-environments and varied across urban and rural space. The overall effect of heatwaves on diseases varies across disease types and geographical contexts (latitudes; inland versus coast). The local heat-disease nexus follows a J-shape function—becoming sharply positive after a certain threshold of heatwaves—reflecting that people with the onset of different diseases have various sensitivity and tolerance to heatwaves. However, such effects are relatively marginal compared to tri-environmental variables. We propose a number of policy implications on reducing urban-rural disparity in healthcare access and service distribution, delineating areas, and identifying the variations of sensitivity to heatwaves across urban/rural space and disease types. Our conceptual framework can be further applied to examine the relationship between other environmental problems and health outcomes.

Field thermo acclimation increases the resilience of Posidonia oceanica seedlings to marine heat waves.

Acclimation is a response that results from chronic exposure of an individual to a new environment. This study aimed to investigate whether the thermal environment affects the early development of the seagrass Posidonia oceanica, and whether the effects of a field-simulated Marine Heat Wave (MHW) on seedlings change depending on acclimation. The experiment was done in the field using a crossed design of Acclimation (acclimated vs unacclimated) and MHW (present vs absent) factors. Acclimation has initially constrained the development of P. oceanica seedlings, but then it increased their resilience to the MHW, under both a morphological and biochemical (fatty acid saturation) level. This treatment could be considered in P. oceanica restoration projects in a climate change-impaired sea, by purposely inducing an increased resistance to heat before transplants.

Evaluating the Spatial Variation of Heatwave Intensity to Enhance Urban Resilience

With global rise in frequency and intensity of natural disaster events, the adverse effects of climate change are becoming increasingly evident. A recent example is the extreme heatwave experienced by western North America which has caused a substantial loss of life and damage to the infrastructure. Research suggests that the intensity of heatwaves is amplified in urban areas due to the contribution of Urban Heat Island effect (UHI) which is largely a function of surrounding urban landscape. In order to develop urban resilience to the extreme heat, it is important to understand the direct relationship between urban form and the temperature elevations caused by the heatwaves. This research examines the disproportionate effects of heatwaves in urban areas and their dependence on urban form by leveraging the microclimatic weather data collected during the 2021 heatwave event in western North America. Strong positive correlations were found between heatwave intensity and both impervious area (PRCC=0.79) and population density (PRCC = 0.83), whereas tree canopy cover was negatively correlated with heatwave intensity (PRCC = -0.89). This analysis can be used to inform urban planning, and to establish proper resilience measures against future heatwave events.

Globally unequal effect of extreme heat on economic growth.

Increased extreme heat is among the clearest impacts of global warming, but the economic effects of heat waves are poorly understood. Using subnational economic data, extreme heat metrics measuring the temperature of the hottest several days in each year, and an ensemble of climate models, we quantify the effect of extreme heat intensity on economic growth globally. We find that human-caused increases in heat waves have depressed economic output most in the poor tropical regions least culpable for warming. Cumulative 1992-2013 losses from anthropogenic extreme heat likely fall between $5 trillion and $29.3 trillion globally. Losses amount to 6.7% of Gross Domestic Product per capita per year for regions in the bottom income decile, but only 1.5% for regions in the top income decile. Our results have the potential to inform adaptation investments and demonstrate how global inequality is both a cause and consequence of the unequal burden of climate change.

The effects of marine heatwaves on acute heat tolerance in corals.

Scleractinian coral populations are increasingly exposed to conditions above their upper thermal limits due to marine heatwaves, contributing to global declines of coral reef ecosystem health. However, historic mass bleaching events indicate there is considerable inter- and intra-specific variation in thermal tolerance whereby species, individual coral colonies and populations show differential susceptibility to exposure to elevated temperatures. Despite this, we lack a clear understanding of how heat tolerance varies across large contemporary and historical environmental gradients, or the selective pressures that underpin this variation. Here we conducted standardised acute heat stress experiments to identify variation in heat tolerance among species and isolated reefs spanning a large environmental gradient across the Coral Sea Marine Park. We quantified the photochemical yield (Fv /Fm ) of coral samples in three coral species, Acropora cf humilis, Pocillopora meandrina, and Pocillopora verrucosa, following exposure to four temperature treatments (local ambient temperatures, and + 3°C, +6°C and + 9°C above local maximum monthly mean). We quantified the temperature at which Fv /Fm decreased by 50% (termed ED50) and used derived values to directly compare acute heat tolerance across reefs and species. The ED50 for Acropora was 0.4-0.7°C lower than either Pocillopora species, with a 0.3°C difference between the two Pocillopora species. We also recorded 0.9°C to 1.9°C phenotypic variation in heat tolerance among reefs within species, indicating spatial heterogeneity in heat tolerance across broad environmental gradients. Acute heat tolerance had a strong positive relationship to mild heatwave exposure over the past 35 years (since 1986) but was negatively related to recent severe heatwaves (2016-2020). Phenotypic variation associated with mild thermal history in local environments provides supportive evidence that marine heatwaves are selecting for tolerant individuals and populations; however, this adaptive potential may be compromised by the exposure to recent severe heatwaves.

Heat wave exposure impairs reproductive performance in primiparous sows and gilts in a tropical environment.

We studied the effects of heat waves (HW), defined as three consecutive days with an ambient temperature ≥ 25°C and a temperature and humidity index (THI) > 74, on the reproductive performance of sows. Meteorological data were obtained from the National Institute of Meteorology and reproductive data from a commercial farm with 51,578 inseminations and 49,103 pregnancies from September 5, 2013, to July 12, 2019. Sows were divided into the following groups according to the parity order: group 1 (sows that did not experience HW on the day of insemination) and group 2 (sows exposed to HW on the day of insemination). The percentage of days that pregnant sows were exposed to HW was calculated as 0 to 25% (1), 26 to 50% (2), 51 to 75% (3), and > 75% (4). Out of a total of 2137days, there were 160 HW and more than 10 HW per month, except in May, June, and July. Gilts in group 2 showed a decrease in the percentage of gestation (98.21% and 98.78%, respectively, P = 0.0267) and the percentage of births compared with those in group 1 (95.53% and 96.61, respectively, P = 0.0065). Primiparous sows in group 2 had a higher percentage of abortions than gilts in group 1 (3.20% and 2.42%, respectively; P = 0.0334). Sows exposed to more than 50% HW during gestation produced more mummified piglets than sows exposed to less than 50% HW. The number of stillborn piglets was higher in sows exposed to temperatures above 25% HW during gestation. The occurrence of heat waves in gilts and primiparous sows impairs reproductive performance.

Urban Thermal Comfort - Reality and Challenges

The city is characterised by a specific climate. Depending on the type of land use, the characteristics of the land cover, such as colour and the permeability of the surface, or the construction materials used in the urban space - there are locally large horizontal and vertical differences in air temperature in the city, defined by the local energy balance of the surface area. The varies are represented by the topoclimatic units. Each of the topoclimatic types can be characterised by a specific sensitivity to the occurrence of high air temperature, which has its direct impact on the parameters of thermal bioregulation of an individual living in the urban space. The analysis of topoclimatic conditions is presented on the example of two towns near Warsaw: Mińsk Mazowiecki and Wołomin. We then demonstrate the relationship between topoclimate and human thermal stress under conditions of high and extremely high air temperature. We present how targeted actions in urban space can shape topoclimates and consequently mitigate the effects of heat waves. These measures are of considerable importance in the context of adaptation to forecast climate change. In our opinion, modelling of human thermal stress should be one of the key parameters in spatial planning, among others, as a part of health risk management.

Probabilistic extreme SST and marine heatwave forecasts in Chesapeake Bay: A forecast model, skill assessment, and potential value

We test whether skillful 35-day probabilistic forecasts of estuarine sea surface temperature (SST) are possible and whether these forecasts could potentially be used to reduce the economic damages associated with extreme SST events. Using an ensemble of 35-day retrospective forecasts of atmospheric temperature and a simple model that predicts daily mean SST from past SST and forecast atmospheric temperature, we create an equivalent ensemble of retrospective SST forecasts. We compare these SST forecasts with reference forecasts of climatology and damped persistence and find that the SST forecasts are skillful for up to two weeks in the summer. Then, we post-process the forecasts using nonhomogeneous Gaussian regression and assess whether the resulting calibrated probabilistic forecasts are more accurate than the probability implied by the raw model ensemble. Finally, we use an idealized framework to assess whether these probabilistic forecasts can valuably inform decisions to take protective action to mitigate the effects of extreme temperatures and heatwaves. We find that the probabilistic forecasts provide value relative to a naive climatological forecast for 1-2 weeks of lead time, and the value is particularly high in cases where the cost of protection is small relative to the preventable losses suffered when a heatwave occurs. In most cases, the calibrated probabilistic forecasts are also more valuable than deterministic forecasts based on the ensemble mean and naive probabilistic forecasts based on damped persistence. Probabilistic SST forecasts could provide substantial value if applied to adaptively manage the rapid impacts of extreme SSTs, including managing the risks of catch-and-release mortality in fish and Vibrio bacteria in oysters.

Dry spells and global crop production: A multi-stressor and multi-timescale analysis

More frequent and punctuated severe events such as dry spells are among the more salient manifestations of climate change. Because dry spells often co-occur both with heat waves and with longer-term agricultural drought and their effects may interact, understanding the effects of dry spells and heat waves requires a multi-timescale and multi-stressor perspective. Using a global panel of daily precipitation and temperature from 1979 to 2016, we provide evidence that 4–5 week dry spells that occur during the hottest part of the year depress growth in aggregate crop production. The effects of these extreme events are modified by existing drought, aridity, and by heat waves. Our findings, focused on punctuated events, multiple stressors, and aggregate crop production across the globe, complement prior investigations focused solely on longer-term phenomena, those that study extreme heat or precipitation in isolation, and studies that restrict attention to a small number of crops or locations.

Co-occurring anthropogenic stressors reduce the timeframe of environmental viability for the world's coral reefs.

Anthropogenic disturbances are posing unprecedented challenges to the persistence of ecosystems worldwide. The speed at which these disturbances reach an ecosystem’s tolerance thresholds will determine the time available for adaptation and conservation. Here, we aim to calculate the year after which a given environmental stressor permanently exceeds the bounds of an ecosystem’s tolerance. Ecosystem thresholds are here defined as limits in a given stressor beyond which ecosystems have showed considerable changes in community assembly and functioning, becoming remnants of what they once were, but not necessarily leading to species extirpation or extinction. Using the world’s coral reefs as a case example, we show that the projected effects of marine heatwaves, ocean acidification, storms, land-based pollution, and local human stressors are being underestimated considerably by looking at disturbances independently. Given the spatial complementarity in which numerous disturbances impact the world’s coral reefs, we show that the timelines of environmental suitability are halved when all disturbances are analyzed simultaneously, as opposed to independently. Under business-as-usual scenarios, the median year after which environmental conditions become unsuitable for the world’s remaining coral reefs was, at worse, 2050 for any one disturbance alone (28 years left); but when analyzed concurrently, this date was shortened to 2035 (13 years left). When analyzed together, disturbances reduced the date of environmental suitability because areas that may remain suitable under one disturbance could become unsuitable by any of several other variables. The significance of co-occurring disturbances at reducing timeframes of environmental suitability was evident even under optimistic scenarios. The best-case scenario, characterized by strong mitigation of greenhouse gas emissions and optimistic human development, resulted in 41% of global coral reefs with unsuitable conditions by 2100 under any one disturbance independently; yet when analyzed in combination up to 64% of the world’s coral reefs could face unsuitable environmental conditions by one disturbance or another. Under the worst-case scenario, nearly all coral reef ecosystems worldwide (approximately 99%) will permanently face unsuitable conditions by 2055 in at least one of the disturbances analyzed. Prior studies have indicated the projected dire effects of climate change on coral reefs by mid-century; by analyzing a multitude of projected disturbances, our study reveals a much more severe prognosis for the world’s coral reefs as they have significantly less time to adapt while highlighting the urgent need to tackle available solutions to human disturbances.

Modulation of grape cuticular wax composition following multiple heatwaves influences grape transpiration

Heat stress events (heatwaves) significantly impair grapevine leaf and berry physiology. The prevalence and frequency of heatwaves are predicted to increase in the coming decades, even in moderate climates. Despite this, many facets of heatwave effects on grapevine physiology remain unstudied. In this work, we subjected potted Gewürztraminer grapevines to a single heatwave event at mid-ripening or a double heatwave event at both the onset of ripening and mid-ripening and compared them to respective untreated control vines. The recovery of leaf and grape physiology from both events were analyzed on the day following the event and at harvest maturity through measurements of leaf gas exchange and chlorophyll fluorescence, and grape size, total soluble solids, and cuticular wax composition. Both single heatwave (S-HW) and double heatwave ( D -HW) treatments reduced chlorophyll fluorescence ( Fv/Fm ) by 12.8 % and 6.1 % on the day following the heatwave, respectively. However, values recovered at harvest maturity only by S-HW. Photosynthetic rate (Pn) was not affected by treatments on the day following the heatwave, but was reduced in D -HW by 48 % at harvest maturity. Total soluble solids were also decreased only by D -HW at harvest maturity. Following the D -HW, total berry wax (by 11.8 %), as well as the total contents of triterpenoids (by 11.7 %) and aldehydes (by 14.3 %) were increased significantly at harvest maturity. Fruit cuticular transpiration was reduced by D -HW. Interestingly, this decrease in transpiration was correlated with an increase in the ratio between the two most abundant wax compounds, oleanolic acid and ursolic acid, which are both triterpenoids. This data corroborates to suggest that grapevines are resilient to a single but not a double heatwave event. Future work will further explore the effects of heatwave frequency and recovery on additional facets of leaf physiology and grape quality. • Grapevines were exposed to a single or double heatwave event during ripening. • The double heatwave reduced leaf chlorophyll fluorescence and berry soluble solids. • The double heatwave raised total wax and triterpenoid contents in berries at harvest. • The double heatwave increased the ratio of oleanolic to ursolic acid at harvest. • The oleanolic to ursolic acid ratio correlated with lower cuticular transpiration.

Extreme temperature increases the severity of intracerebral hemorrhage: An analysis based on the cold region of China

Abstract Objective The purpose of this study was to find a suitable model to evaluate the relationship between temperature and intracerebral hemorrhage (ICH) and explore the effects of cold spells and heat waves on the clinicopathological parameters of ICH patients. Methods We conducted a retrospective study based on the ICH admission in the First Affiliated Hospital of Harbin Medical University from 2015 to 2020 (N = 11 124). The relationship between different seasons and the number of patients with ICH was explored. Poisson Akaike information criterion (AIC) was used to select the optimal model for temperature and ICH. Binary logistic regression analysis was used to investigate the association between extreme temperatures and clinicopathological features. Results Hospital admissions for patients with ICH showed monthly changes. The optimal cold spell was defined as the daily average temperature &lt; 3rd percentile, lasting for five days, while the optimal heat wave was defined as the daily average temperature &gt;97th percentile, lasting for three days. Based on the generalized extreme weather model, cold climate significantly increased the risk of hematoma volume expansion (OR 1.003; 95% CI: 1.000–1.005, P = 0.047). In the optimal model, the occurrence of cold spells and heat waves increased the risk of midline shift in both conditions (OR 1.067; 95% CI: 1.021–1.115, P = 0.004; OR 1.077; 95% CI: 1.030–1.127, P = 0.001). Conclusion Our study shows that seasonal cold spells and heat waves are essential factors affecting ICH severity, and targeted preventive measures should be taken to minimize the pathological impacts.

Does the meteorological origin of heat waves influence their impact on health? A 6-year morbidity and mortality study in Madrid (Spain)

BackgroundIn Spain, two synoptic-scale conditions influence heat wave formation. The first involves advection of warm and dry air masses carrying dust of Saharan origin (North African Dust (NAF) = 1). The second entails anticyclonic stagnation with high insolation and stability (NAF) = 0). Some studies show that the meteorological origin of these heat waves may affect their impact on morbidity and mortality. ObjectiveTo determine whether the impact of heat waves on health outcomes in Madrid (Spain) during 2013–2018 varied by synoptic-scale condition. MethodologyOutcome data consist of daily mortality and daily hospital emergency admissions (morbidity) for natural, circulatory, and respiratory causes. Predictors include daily maximum and minimum temperatures and daily mean concentrations of NO2, PM10, PM2.5, NO2, and O3. Analyses adjust for insolation, relative humidity, and wind speed. Generalized linear models were performed with Poisson link between the variables controlling for trend, seasonality, and auto-regression in the series. Relative Risks (RR) and Attributable Risks (AR) were determined. The RRs for mortality attributable to high temperatures were similar regardless of NAF status. For hospital admissions, however, the RRs for hot days with NAF = 0 are higher than for days with NAF = 1. We also found that atmospheric pollutants worsen morbidity and mortality, especially PM10 concentrations when NAF = 1 and O3 concentrations when NAF = 0. ResultsThe effect of heat waves on morbidity and mortality depends on the synoptic situation. The impact is greater under anticyclonic stagnation conditions than under Saharan dust advection. Further, the health impact of pollutants such as PM10 and O3 varies according to the synoptic situation. ConclusionsBased on these findings, we strongly recommend prevention plans to include data on the meteorological situation originating the heat wave, on a synoptic-scale, as well as comprehensive preventive measures against the compounding effect of high temperatures and pollution.

Main and added effects of heatwaves on hospitalizations for Mental and Behavioral Disorders in a tropical megacity of Vietnam

BACKGROUND AND AIM: Vietnam is highly vulnerable to climate change-related extreme weather events such as heatwaves. This study assesses the association between heatwaves and hospitalizations due to mental and behavioral disorders (MBDs) in Ho Chi Minh City (HCMC). METHODS: We collected daily MBD hospital admissions data at the HCMC Mental Health Hospital from 2017 to 2019. Heatwaves effects were characterized into the main effect (i.e., the intensity of temperature during heatwaves) and the added effect (i.e, the duration of heatwaves). Time series Poisson regression coupled with a distributed lag linear model (DLM) was used to quantify the 14-day lags effect of heatwaves. Confounders including long-term trend, seasonality, days of the week, holidays, relative humidity were included in the model. RESULTS: Heatwaves increased all-cause MBD hospitalization by 62% (95%Cl, 36%–93%) for the main effect, and by 8% (95% Cl, -3%–19%) for the added effect. Noticeably, the group aged 18 to 60 years old was affected by the main effect of the heatwave, while the group aged 61 years and older was affected by the added effect of the heatwave. The effects of heatwaves differed among groups of MBD hospitalizations. The mental and behavioral disorder group due to psychoactive substance use was significantly affected by the main effect of heatwaves (RR:2.21; 95%Cl:1.55–3.15). The group of schizophrenia, schizotypal and delusional disorders were highly vulnerable towards both the main and the added effect of heatwaves with RR=1.50 (95%CI, 1.20–1.86) and RR = 1.14 (95%CI, 1.01–1.30), respectively. CONCLUSIONS: These results aroused the need for adequate heat warning and adaptation programs when temperatures are not too high but prolonged, particularly with the elderly

Effects of heat exposure on occupational injuries in the agricultural sector in Italy

Background and aim – The health effects of extreme temperatures at population level are well known. However, the effects on occupational injuries in different sectors have been scarcely investigated. Methods - We collected work-related injuries in the agriculture sector occurring in the 8,090 Italian municipalities from the Italian national workers’ compensation authority (INAIL) between 2014-2018. Daily air temperatures from Copernicus ERA5-land were used to define exposure at municipality level. First, we applied distributed lag non-linear models (DLNM) to estimate the association between daily mean air temperature and injuries at regional level; then meta-analysed results to have overall estimates. The relative risk (RR) and attributable cases of agriculture-related injuries for an increase in mean temperature above the 75th percentile were estimated, as well as heatwave effects. Analysis were also stratified by age, duration of leave and professional qualification. Results - Analysis were conducted on 150,422 agricultural injuries. The overall relative risk of agricultural work-related injuries for an increase in temperatures was 1.13 (95%CI: 1.08; 1.18). The number of injuries attributable to heat is of 2050 cases in the considered period. A higher risk was observed among young workers (1.23 95% CI: 1.14; 1.34) and seasonal workers (1.25 95% CI: 1.03; 1.52). When considering duration of leave, a proxy of severity of heat-related injuries, the greatest risk and frequency was observed for short duration between 0-14 days (1.21 95% CI: 1.10; 1.33) with a decreasing trend. Considering extreme heat wave events, the risk of injuries in the agricultural sector was of 1.04 (95% CI: 1.01; 1.08). Conclusions - Occupational exposure to extreme temperatures is a critical issue considering climate change especially among sectors engaged in outdoor and labour-intensive activities such as the agricultural sector. These results can help promote specific prevention actions for workers. Keywords - Work-related injuries; heat waves; agricultural sector.