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Climate extremes: The worst heat waves to come
Abstract
The combination of high temperatures and humidity could, within just a century, result in extreme conditions around the Persian Gulf that are intolerable to humans, if climate change continues unabated.
... Heat-humidity effects have prompted decades of study in military, athletic, and occupational contexts (8,9). However, consideration of wet-bulb temperature (TW) from the perspectives of climatology and meteorology began more recently (10,11). ...
... S1). In the literature to date, there have been no observational reports of TW exceeding 35°C and few reports exceeding 33°C (9,11,14,15). The awareness of a physiological limit has prompted modeling studies to ask how soon it may be crossed. ...
... Other >31°C hotspots in the weather station record emerge through surveying the globally highest 99.9th TW percentiles: eastern coastal India, Pakistan and northwestern India, and the shores of the Red Sea, Gulf of California, and southern Gulf of Mexico ( Fig. 1). All are situated in the subtropics, along coastlines (typically of a semienclosed gulf or bay of shallow depth, limiting ocean circulation and promoting high SSTs), and in proximity to sources of continental heat, which together with the maritime air comprise the necessary combination for the most exceptional TW (11). That subtropical coastlines are hotspots for heat stress has been noted previously (23,24); our analysis makes clear the broad geographic scope but also the large intraregional variations (Fig. 1). ...
An analysis of global observations of extreme humid heat and the alarming implications for continued climate change.
... Heat-humidity impacts have prompted decades of study in military, athletic, and occupational contexts (8,9). However, consideration of TW from a climate perspective only began more recently (10,11). ...
... 10 Because the ideal assumptions are almost never met, severe impacts occur at much lower values -for example, most regions affected by the deadly 2003 European and 2010 Russian heatwaves experienced TW no greater than 28°C (Fig. S1). In the literature to date, there have been no observational reports of TW exceeding 35°C, and few reports exceeding 33°C (9,11,14,15). The awareness of a physiological limit has prompted modeling studies to ask how soon it may be 15 crossed. ...
... In contrast to these earlier studies, we find large numbers of TW exceedances of 31°C and 33°C, and that three stations in the dataset have recorded multiple daily-maximum TW values Other >31°C hotspots emerge through the 99.9 th percentile metric: eastern coastal India, northwestern India, Pakistan, northwestern Australia, and the shores of the Red Sea, Gulf of California, and Gulf of Mexico ( Fig. 1). All are situated in the subtropics, along coastlines (often with a semi-enclosed gulf or bay of shallow depth, limiting ocean circulation and facilitating 15 high SSTs), and in proximity to sources of continental heat, which along with the maritime air seem to be the necessary ingredients for truly extraordinary TW values to occur (11). The exception to the coastline rule is western South Asia, perhaps due to the efficient inland transport of humid air by the summer monsoon in combination with large-scale irrigation (15,21). ...
... Heat-humidity effects have prompted decades of study in military, athletic, and occupational contexts (8,9). However, consideration of wet-bulb temperature (TW) from the perspectives of climatology and meteorology began more recently (10,11). ...
... S1). In the literature to date, there have been no observational reports of TW exceeding 35°C and few reports exceeding 33°C (9,11,14,15). The awareness of a physiological limit has prompted modeling studies to ask how soon it may be crossed. ...
... Other >31°C hotspots in the weather station record emerge through surveying the globally highest 99.9th TW percentiles: eastern coastal India, Pakistan and northwestern India, and the shores of the Red Sea, Gulf of California, and southern Gulf of Mexico ( Fig. 1). All are situated in the subtropics, along coastlines (typically of a semienclosed gulf or bay of shallow depth, limiting ocean circulation and promoting high SSTs), and in proximity to sources of continental heat, which together with the maritime air comprise the necessary combination for the most exceptional TW (11). That subtropical coastlines are hotspots for heat stress has been noted previously (23,24); our analysis makes clear the broad geographic scope but also the large intraregional variations (Fig. 1). ...
Humans’ ability to efficiently shed heat has enabled us to range over every continent, but a wet-bulb temperature (TW) of 35°C marks our upper physiological limit, and much lower values have serious health and productivity impacts. Climate models project the first 35°C TW occurrences by the mid-21st century. However, a comprehensive evaluation of weather station data shows that some coastal subtropical locations have already reported a TW of 35°C and that extreme humid heat overall has more than doubled in frequency since 1979. Recent exceedances of 35°C in global maximum sea surface temperature provide further support for the validity of these dangerously high TW values. We find the most extreme humid heat is highly localized in both space and time and is correspondingly substantially underestimated in reanalysis products. Our findings thus underscore the serious challenge posed by humid heat that is more intense than previously reported and increasingly severe.
... The past few years have witnessed numerous heatwaves around the world reported as "record breaking," "abnormal," "rare," and "catastrophic" by the media (Ceccherini et al., 2017;Chen & Li, 2017;Coumou & Rahmstorf, 2012;Russo et al., 2015). Under projected future climate warming, the intensity, frequency, and duration of severe heatwaves are likely to increase further (Jones et al., 2015;Lau & Nath, 2014;Mora et al., 2017;Schär, 2016;Schoetter et al., 2015). ...
... A large body of literature has suggested that future GHG increases will very likely enhance the duration, intensity, and frequency of heat extremes across the world (Jones et al., 2015;Lau & Nath, 2014;Meehl & Tebaldi, 2004;Mishra et al., 2017;Mora et al., 2017;Russo et al., 2014;Schär, 2016;Schoetter et al., 2015). However, very little attention has been devoted to contrasting the roles of future GHG increases and aerosol reductions in future heatwave characteristic projections. ...
Using the Community Earth System Model Large Ensemble experiments, we investigate future heatwaves under the Representative Concentration Pathway 8.5 scenario, separating the relative roles of greenhouse gas increases and aerosol reductions. We show that there will be more severe heatwaves (in terms of intensity, duration and frequency) due to mean warming, with minor contributions from future temperature variability changes. While these changes come primarily from greenhouse gas (GHG) increases, aerosol reductions contribute significantly over the Northern Hemisphere. Furthermore, per degree of global warming, aerosol reductions induce a significantly stronger response in heatwave metrics relative to GHG increases. The stronger response to aerosols is associated with aerosol‐cloud interactions which are still poorly understood and constrained in current climate models. This suggests that there may exist large uncertainties in future heatwave projections, highlighting the critical significance of reducing uncertainties in aerosol‐cloud interactions for reliable projection of climate extremes and effective risk management.
... Floods and heat waves are some of the most common issues linked to climate change, with current predictions showing an increase in their frequency and intensity in the near future [1][2][3][4]. However, the impacts of our changing climate on human health include not only these dangerous climatic events, but also an increase in zoonotic diseases, such as Lyme disease. ...
... Perceived social norms Responses to the question were used to measure participants' perception of social norms related to the implementation of LDPB: if I adopt behaviors to protect myself against tick bites and therefore Lyme disease in the next year, people who are important to me will support my choice. Participants rated the item on a four-point scale ranging from "strongly agree" (4) to "strongly disagree" (1). ...
Background:
Recent evidence suggests that climate change and other factors are leading to the emergence of Lyme disease in the province of Quebec, where it previously did not exist. As risk areas expand further north, the population can adopt specific preventive behaviors to limit chances of infection. The objectives of this study were to (1) create an index of Lyme disease prevention behaviors (LDPB), and (2) use the theory of planned behavior (TPB) to explain the decision-making process of people who choose to adopt LDPB.
Methods:
A sample of 1959 adults living in a Lyme disease risk area completed a questionnaire by phone (n = 1003) or on the Web (n = 956). The questionnaire measured whether they did or did not adopt the LDPB proposed by public health officials. It also measured some TPB variables, including their attitude or perceived social norms regarding LDPB.
Results:
Our findings led to the creation of a Lyme disease prevention index consisting of 10 behaviors, down from the 19 behaviors initially considered for inclusion in the index. Rates of adoption of each behavior varied tremendously, from 4.30 to 83.80%. All variables of the TPB model (attitude, social norms, and perceived control) were significantly associated with intention to adopt preventive behaviors. Intention itself was significantly associated with adoption of LDPB. Likewise, risk perception was positively correlated with the adoption of LDPB.
Conclusions:
This study led to the creation of a Lyme disease prevention index that can be used by public health agencies, researchers, and professionals to monitor the evolution over time of individuals' LDPB adoption rates. It also showed the usefulness of the TPB in understanding the adoption of LDPB and how intention to adopt such behaviors is formed.
... Studies have demonstrated that climate change will increase air temperature across the Middle East to thresholds not tolerable for human body, especially around the Persian Gulf (Im et al., 2017;Pal and Eltahir, 2016). Schär (2016) discussed that the air temperature has already exceeded the postulated tolerance threshold in some humid areas around the Persian Gulf (e.g. Bandar Mahshahr, Iran). ...
Climate change will substantially exacerbate extreme temperature and heatwaves. The impacts will be more intense across the Middle East and North Africa (MENA), a region mostly characterized by hot and arid climate, already intolerable for human beings in many parts. In this study, daily climate data from 17 fine-resolution Regional Climate Models (RCMs) are acquired to calculate wet-bulb temperature and investigate the mortality risk for people aged over 65 years caused by excessive heat stress across the MENA region. Spatially adaptive temperature thresholds are implemented for quantifying the mortality risk, and the analysis is conducted for the historical period of 1951–2005 and two future scenarios of RCP4.5 and RCP8.5 during the 2006–2100 period. Results show that the mortality risk will increase in distant future to 8–20 times higher than that of the historical period if no climate change mitigation is implemented. The coastal regions of the Red sea, Persian Gulf, and Mediterranean Sea indicate substantial increase in mortality risk. Nonetheless, the risk ratio will be limited to 3–7 times if global warming is limited to 2 °C. Climate change planning and adaptation is imperative for mitigating heat-related mortality risk across the region.
... ex. sécheresses, tempêtes hivernales ; (Beniston et al., 2007;Schär, 2016). L'évaluation de la sensibilité des espèces végétales et de la résilience des écosystèmes de montagne face à ces changements sont donc primordiaux. ...
Les régions alpines sont particulièrement sensibles aux changements climatiques en cours. Ainsi, l’ouest des Alpes s’est réchauffé deux fois plus vite que l’hémisphère Nord au cours du XXème siècle. Les rythmes saisonniers des arbres, comme beaucoup d’autres organismes, sont fortement modifiés par le réchauffement climatique. La phénologie et les variations temporelles fines du climat apparaissent comme des composantes incontournables à prendre en compte pour prédire la répartition des espèces. L’objectif principal de ce travail de thèse a été de comprendre la réponse de la phénologie des espèces arborées au réchauffement climatique dans les Alpes et de développer des outils pour évaluer cette réponse dans le futur. Pour atteindre cet objectif nous avons utilisé des données phénologiques (débourrement, floraison, senescence foliaire,) pour le noisetier, le frêne, le bouleau, le mélèze et l’épicéa, issues du programme de sciences participatives Phénoclim.Nos résultats montrent que le réchauffement de l’hiver retarde la levée de la dormance des bourgeons et par conséquent les dates de débourrement et de floraison le long du gradient d’altitude. Cet effet est plus important à basse altitude. La robustesse des projections des modèles de répartition basés sur les processus dépend fortement de la robustesse des modèles phénologiques qu’ils utilisent. En comparant des modèles phénologiques présentant différents niveaux de complexité nous avons montré que les modèles basés sur les processus étaient les plus robustes particulièrement lorsque l’estimation de leurs paramètres reposait sur une estimation directe à l'aide de mesures expérimentales. Les modèles prévoient une réduction des écarts entre les dates de débourrement le long du gradient d'altitude pour toutes les espèces d'ici la fin du 21e siècle. Ceci est dû d’une part à un avancement des dates de débourrement à haute altitude et d’autre part à un retard des dates de débourrement à basse altitude. Nous avons également testé de nouvelles hypothèses sur le déterminisme environnemental de la croissance cellulaire dans les bourgeons, mais aucune des hypothèses testées n’a significativement amélioré les performances des modèles. Nous avons ensuite intégré les modèles phénologiques les plus performants que nous ayons obtenus au modèle d’aire de répartition basé sur les processus PHENOFIT. Nous avons réalisé pour la première fois avec ce modèle des simulations à haute résolution spatiale. Les projections du modèle montrent que les espèces arborées devraient se déplacer vers le haut du gradient d’altitude. Cependant, des phénomènes d’extinction locale pourraient avoir lieu dans les fonds des vallées liés à des dates de floraison trop tardives qui diminuerait le succès reproducteur des individus. Selon les espèces, la limite altitudinale supérieure serait contrôlée par le risque d'exposition au gel tardif des fleurs ou par la longueur de la saison de croissance qui détermine le temps disponible pour la maturation des fruits.L’ensemble de ces résultats nous a permis d’apporter des éléments de réponse sur la dynamique future des écosystèmes forestiers altitudes face au réchauffement climatique. Ils nous ont également permis de montrer que les données du programme Phénoclim étaient de qualité suffisante pour être utilisées dans des travaux de recherche scientifique.
... Heat wave literature, particularly studies focused on the physical mechanisms driving onset and intensity traditionally focus on the sensible heat contribution to atmospheric heat content through analysis of maximum temperature (Diffenbaugh & Ashfaq, 2010;Mueller & Seneviratne, 2012;Oswald & Rood, 2014;Russo et al., 2014). However, recent studies highlight the increasingly important role of atmospheric humidity during heat waves and societal vulnerability to these events (Schär, 2016;Pal & Eltahir, 2016;Mitchell et al., 2016); the nature of heat events is dependent on local soil moisture availability and antecendent precipitation conditions (Ford & Schoof, based heat wave descriptions with metrics that are sensitive to humidity, such as dew point temperature and wet bulb temperature (Bentley et al., 2008;Pal & Eltahir, 2016). Pielke et al. (2004) recommend moist static energy to represent total atmospheric heat content, as it accounts for both temperature and moisture energy contributions. ...
Recent studies point to a significant rise in the number of summer extreme weather events that correspond with the presence of amplified, quasi‐stationary mid‐tropospheric planetary waves, weakened atmospheric circulation in the Northern Hemisphere (NH), and coincide with reduced summer Arctic sea ice cover. This study explores potential connections between 1979‐2016 summer heat wave frequency across the United States (U.S.) and regional Arctic sea ice extent in various Arctic basins. Most notable SIE interannual relationships exist across the southern Plains and southeastern U.S. during low Hudson Bay (HB) summer SIE. Locally increased frequencies of summer heat waves coincide with unseasonably warm conditions developed and sustained by the presence of an omega blocking pattern situated over the southern U.S. throughout summer. The block appears following anomalous atmospheric warming and reduced mean zonal winds observed throughout spring (MAM) over northeastern Canada, the northwestern Atlantic basin, and Greenland. Spring pre‐conditioning of summer ice melt is favored by the presence of strong negative phase of the North Atlantic Oscillation and positive Greenland Blocking Index. Summer synoptic flow related to HB ice melt over North America (NA) appears to be influenced by the background state of atmospheric variability, namely the positive phase of the Atlantic Multidecadal Oscillation. Antecedent local humidity, soil moisture, and precipitation conditions are shown to influence the “flavor” of the heat waves, which are more likely to be oppressive in the southeastern U.S. and extreme across the southern Plains during summers experiencing low Hudson SIE.
... It captures the comprehensive effects of air temperature and humidity on the heat exchange between the environment and human body. Over the past four decades, the wet bulb temperature has been shown to increase with temperature and humidity changes [12,15,16]. ...
With the changes in global temperature and humidity, heat stress is expected to intensify in the coming decades. Under the scenario that greenhouse gas emissions keep increasing until the end of this century, there is the possibility of extensive global exposure to high heat stress. While under new mitigation efforts (as part of the Paris Agreement, signatory nations pledged to implement the Intended Nationally Determined Contributions (INDCs) for emission reductions), the regional response of heat stress to pledged emission reductions remains unclear. In this study, we analyze the heat stress response in global hotspot regions, targeting emission scenarios resulting from the INDCs pledges. Our study revealed that under the INDCs-continuous mitigation, the heat stress effect in global hotspot regions (North China, South Asia, and the Amazon) is estimated to be lower than 29 °C in the next three decades and to be from >33 °C to less than 30 °C to this century end. The heat stress effect indicates a great reduction at the continuous mitigation compared with the delayed mitigation, and the population exposed to dangerous heat stress would also decrease approximately one order of magnitude. If limiting warming to a lesser amount (1.5/2 °C targets), significantly further reduction of the population exposed to heat stress in the middle and low latitudes can be achieved, thus avoiding the adverse effects associated with heat stress. Therefore, the national intended mitigation actions under the Paris Agreement will play a crucial role in reducing the heat stress risk in these hot and humid regions. These findings will help to improve the understanding of the future risks of heat stress and are crucial for mitigation and adaptation actions in hotspot areas (approximately 1/3 of the world’s population).
... Yet, the apparent temperature (AP) (the human-perceived equivalent temperature) has increased faster than air temperature over land especially in low latitudes and is expected to continue in the future, with the summertime increase in AP-based thermal discomfort outpacing the wintertime decrease in thermal discomfort [30]. It is expected that the simultaneous occurrence of higher air temperature and humidity could make climate conditions in some areas intolerable to humans in the future [28,31]. ...
Intensification of extreme temperatures combined with other socioeconomic factors may exacerbate human thermal risk. The disastrous impacts of extreme weather during the last two decades demonstrated the increased vulnerability of populations even in developed countries from Europe, which are expected to efficiently manage adverse weather. The study aims to assess trends in the exposure of European populations to extreme weather using updated historical climatic data in large European cities of different local climates and a set of climatic and bioclimatic indices. Colder cities experience higher warming rates in winter (exceeding 1 °C/decade since the mid-1970s) and warmer cities in summer. Hot extremes have almost tripled in most cities during the last two or three decades with simultaneous advancing of hot weather, while northernmost cities have experienced an unprecedented increase in the heat waves frequency only during the last decade. Bioclimatic indices suggested a robust tendency towards less cold-related stress (mainly in cold cities) and more heat-related stress in all cities. A doubling or tripling in the frequency of heat-related ‘great discomfort’ was found in southern cities, while in the cities of northern Europe, heat-related ‘discomfort’ conditions are becoming increasingly more frequent and have nearly quadrupled during the last decade.
... In similar works, observations and/or simulations indicate that the increase in air temperature is accompanied by an increase in the humidity ratio but also in changes in the maximum wet-bulb temperatures [51]. There is the danger that simultaneous occurrence of higher air temperature and humidity could make climate conditions in some areas intolerable to humans in the future [52]. ...
As climatic conditions affect the energy performance of buildings, the changes in outdoor air temperature and humidity will inevitably lead to significant alterations in energy consumption and costs for the heating, ventilating and air conditioning (HVAC) of buildings. The availability and quality of climatic data play an important role in the accuracy of energy analysis results. In this study, the hourly temperature and relative humidity of outdoor air measurements, for a period of three decades (1983–2012), recorded at the climatic station of the National Observatory of Athens were processed, and an up-to-date set of specific data for the application of bin methods was produced and presented. The data were then used to calculate changes in the energy demands in a typical office building throughout the specified period. Results showed a progressive reduction in the low and increase in the high temperature intervals, leading to an increase in the building’s annual energy requirements for air conditioning of up to 14.5% from the first to the third decade, with decrease in the energy demands for heating and increase in the energy demands for cooling.
... Furthermore, some other studies have showed prolonged periods of hightemperature exposure, which was usually defined as a heatwave event, can significantly heighten the risk (Kent et al. 2014;Sun et al. 2019;Wang et al. 2013). In the context of climate change, the frequency and intensity of heatwaves are expected to increase (Hoegh-Guldberg et al. 2018;Schär 2016), which will accordingly add to the existing global PTB burden. ...
Background:
Both extreme heat and air pollution exposure during pregnancy have been associated with preterm birth; however, their combined effects are unclear.
Objectives:
Our goal was to estimate the independent and joint effects of heatwaves and fine particulate matter [PM
<
2.5
μ
m
in aerodynamic diameter (
PM
2.5
)], exposure during the final gestational week on preterm birth.
Methods:
Using birth registry data from Guangzhou, China, we included 215,059 singleton live births in the warm season (1 May-31 October) between January 2015 and July 2017. Daily meteorological variables from 5 monitoring stations and
PM
2.5
concentrations from 11 sites were used to estimate district-specific exposures. A series of cut off temperature thresholds and durations (2, 3, and 4 consecutive d) were used to define 15 different heatwaves. Cox proportional hazard models were used to estimate the effects of heatwaves and
PM
2.5
exposures during the final week on preterm birth, and departures from additive joint effects were assessed using the relative excess risk due to interaction (RERI).
Results:
Numbers of preterm births increased in association with heatwave exposures during the final gestational week. Depending on the heatwave definition used, hazard ratios (HRs) ranged from 1.10 (95% CI: 1.01, 1.20) to 1.92 (1.39, 2.64). Associations were stronger for more intense heatwaves. Combined effects of
PM
2.5
exposures and heatwaves appeared to be synergistic (
RERIs
>
0
) for less extreme heatwaves (i.e., shorter or with relatively low temperature thresholds) but were less than additive (
RERIs
<
0
) for more intense heatwaves.
Conclusions:
Our research strengthens the evidence that exposure to heatwaves during the final gestational week can independently trigger preterm birth. Moderate heatwaves may also act synergistically with
PM
2.5
exposure to increase risk of preterm birth, which adds new evidence to the current understanding of combined effects of air pollution and meteorological variables on adverse birth outcomes. https://doi.org/10.1289/EHP5117.
... Mean temperatures measured at Basra range from 12.2°C in January to 34.5°C in July 34 , when the area is subject to dust storms 35 and some of the most severe heat waves worldwide. 36 Evaporation is significantly lower in Lower Mesopotamia, reaching around 2,000 mm a -1 at Basra, where relative air humidity is among the highest in Iraq throughout the year due to its proximity to the Arabian Gulf coast. 37 ...
Mesopotamia, known as the cradle of civilisation, gave rise to the first state-based urban societies with sophistic political hierarchies. Its rich history full of important cultural achievements was accompanied by fundamental environmental changes over the Holocene. While geo-bio-archives from the broader region reflect slightly varying climate histories, there is a clear consensus on a more humid climate regime during the Early Holocene, triggering early rain-fed agricultural practices in Northern Mesopotamia representing the foundation of initial urbanisation. In the southern basin, declining rainfall and higher competition for natural resources at a somewhat later stage in combination with the development of irrigation techniques and the transgression of the Arabian Gulf seem to have contributed to the formation of complex state-based urban societies at sites such as Eridu, Ur, and Uruk, where landscape dynamics are well-preserved in the stratigraphic record. Against the background of long-term climate trends, it seems that also Rapid Climate Change events—short-term climatic anomalies such as identified around 8,200, 5,200, or 4,200 BP—have taken their toll on Mesopotamian people. Many links between changes in climate and landscape, and socio-technical adaptation based on interdisciplinary research seem straightforward, especially where confirmation exists by cuneiform texts or archaeological evidence. The gap in chronological resolution between rather precise information on historical state development on the one hand, and on climatic changes with a much higher uncertainty on the other hand, may generate an elusive fit between records and requires caution in any attempt of environmental determinism when trying to explain cultural history.
... Sustainable Development Goals 3 and 11, (United Nations, 2015). There is extensive evidence that anthropogenic climate change, both observed and modelled, continues to raise the frequency and intensity of extreme heat events, especially in urban regions and their public areas (Bastin et al., 2019;Christidis, Jones, & Stott, 2014;Russo, Sillmann, & Fischer, 2015;Schär, 2015;Tomczyk & Bednorz, 2016;Wang, Jiang, & Lang, 2017;Wouters et al., 2017;Zhao et al., 2018). Heat extremes can be detrimental to human health, including dehydration, discomfort or exhaustion (de' Donato et al., 2015;Keeler et al., 2019;Lafortezza, Carrus, Sanesi, & Davies, 2009;Nikolopoulou & Lykoudis, 2006;Ragettli, Vicedo-Cabrera, Schindler, & Roosli, 2017;Schuster, Honold, Lauf, & Lakes, 2017;Vogel, Zscheischler, Wartenburger, Dee, & Seneviratne, 2019;Zhao et al., 2018) and can increase heat-related mortality (de' Donato et al., 2015;Lafortezza et al., 2009;Muthers, Laschewski, & Matzaraki, 2017;Ragettli et al., 2017;Rüegg, 2019;Schuster et al., 2017). ...
Cities are particularly sensitive to the effects of climate change, causing an increasing incidence of heat waves. Extreme temperatures can impair the use of public spaces in cities, as heat stress endangers human well-being and health. Identifying suitable adaptation measures to maintain the full functionality of public spaces requires a multidimensional approach, accounting for interrelated scientific, social, and practical aspects. As one result we introduce an inter- and transdisciplinary concept that addresses the challenge of adapting public spaces to climate change. Additionally we present a pilot study from Heidelberg, Germany, where a new, sustainable urban quarter experienced more pronounced heat stress than the historic city centre in the hot and dry summer of 2018. The study shows the suitability of our approach to identify appropriate heat adaptation measures. Solar potential modelling and mental map surveys proved to be particularly effective methods. We find that adaptation measures generate synergy effects by improving both climatic and social conditions.
... Extreme thermal stress events have considerably increased in recent years, both in frequency and in magnitude, and this trend is expected to continue with future global warming, especially in some world regions as southwest Asia [1,2]. This will most probably exacerbate other challenges, such as the buildings energy use for cooling with consequent greenhouse gas (GHG) emissions; the ability to work resulting in lower productivity; the durability of building materials and infrastructures, the possibility to use public spaces thus constraining social life and, above all, public health directly as well as by increasing the burden of air pollution. ...
According to the challenge of global warming, trees play an effective role in reducing heat islands and improving thermal comfort. In this study, the impact of urban greening on microclimate and pedestrian comfort is studied using ENVI met v4 for a residential district in Tabriz, Iran. In-situ measurements of air temperature and relative humidity have been preliminary performed on ten points in the studied site and collected data used to successfully validate the model. Four scenarios with different trees species and patterns were simulated during typical summer and winter days, to assess benefits and disadvantages during different seasons, in terms of air temperature (Ta) and relative humidity (RH), mean radiant temperature (Tmrt) and physiologically equivalent temperature (PET). Result showed that the best scenario provides great summer cooling without compromising winter comfort. In summer Ta and Tmrt are decreased by respectively 0.29 °C and 20.04 °C; while in winter, they reach respectively 6.92 °C and 13.22 °C, compared the reference scenario characterised by 6.28 °C (Ta) and 23.47 °C (Tmrt). These results in a summer PET improvement from 34.92 °C to 26.16 °C, thus moving from an original hot thermal sensation to a slightly warm one. Based on the outcomes of the study, it is possible to provide useful design recommendation for urban adaptation plans.
... For instance, in eastern China, the risks associated with increased exposure to extreme heat are compounded by the large human population in that region [Jones et al., 2015]. Furthermore, the elderly and the ill are more susceptible to the effects of extreme heat [Schär, 2015]. With an increasing and aging population, the threat to human health from heat waves in the current century may be more severe than previously thought; thus, efforts to mitigate the effects of heat waves are essential for the inhabitants of China. ...
Heat waves trigger substantial social and environmental impacts and even cause massive civilian casualties in extreme cases. Observations show the areas affected by heat waves have increased over China, with the most extreme heat wave occurring during the past five decades. Here we show that both trends can be attributed to anthropogenic influences. We report that under the moderate Representative Concentration Pathways 4.5 scenario, anthropogenic influences will increase the risk of occurrence of the observed maximum Heat Wave Magnitude Index in the late 21st century and will cause a more than tenfold increase in the likelihood of the strongest events on record recurring across more than half China. More than 50% of land area in China is projected to be affected by intense heat waves. Our results show that over eastern China, the extremes in heat distribution are more sensitive to precipitation deficits, indicating stronger heat wave amplification trends to occur under drier conditions. The likelihood of concurrent droughts and heat waves is expected to increase in large parts of China in the late 21st century.
... Forest dieback related to climate extremes has been observed in most regions of the world (Allen et al., 2010;Anderegg et al., 2012Anderegg et al., , 2015. In particular heat waves combined with drought, which are increasing in frequency and duration (Meehl and Tebaldi, 2004;Schär, 2015), could be a major trigger of tree mortality (Williams et al., 2012;Allen et al., 2015), yet our understanding of physiological processes within trees to such extremes is scarce. ...
Climate extremes are likely to occur more frequently in the future, including a combination of heat waves and drought. However, the responses of trees to combined stress and their post-stress recovery are not fully understood yet. Therefore, this study investigated the responses of semi-arid Pinus halepensis seedlings to moderate drought, heat and combined heat-drought stress, as well as post-stress recovery. The seedlings were grown under controlled conditions and exposed to two 4-days-long heat periods, reaching air temperature maxima of 42 • C and vapor pressure deficit (VPD) of 7 kPa. Day-and nighttime canopy gas exchange was measured and differences in shoot and root allocation of non-structural carbohydrate (NSC) compounds (soluble sugars, starch, cyclitols, and carboxylic acids) assessed. Fluorescence parameters, nitrate levels, proline content and shoot water potential (ψ) provided additional indicators for stress severity and recovery performance. During the heat periods, net photosynthesis and stomatal conductance decreased immediately. This decline was modest under well-watered conditions, with transpiration and dark respiration rates remaining high and despite reductions in root NSC content, trees recovered following heat release. This was not the case in the heat-drought treatment, where stress resulted in high mortality rates and the few surviving seedlings showed reduced gas exchange rates and low root NSC content, while leaf nitrate and proline remained elevated even 3 weeks after heat release. Shoot ψ indicated that hydraulic failure was not the reason for mortality in the heat-drought seedlings. Instead, we argue that low transpiration rates, which resulted in needle temperatures >47 • C during heat stress (6 • C above air temperature) have caused irreversible damage. In summary, it could be demonstrated that heat waves in combination with moderate drought can either result in increased mortality or, if the seedlings survive, in delayed recovery. This highlights the potential of an increase in heat wave temperatures to trigger forest decline in semi-arid regions.
... 15 Aug 2017 Lewis et al. 2016). It has been predicted (Meehl & Tebaldi 2004;Sherwood & Huber 2010;Schär 2016;Im et al. 2017) that an increasing rate of temperature extremes will have significant effects on human life. Model predictions need to be supplemented by empirical data on the actual history of extreme temperatures. ...
We use the Global Historical Climatology Network--daily database to calculate a nonparametric statistic that describes the rate at which all-time daily high and low temperature records have been set in nine geographic regions (continents or major portions of continents) during periods mostly from the mid-20th Century to the present. This statistic was defined in our earlier work on temperature records in the 48 contiguous United States. In contrast to this earlier work, we find that in every region except North America all-time high records were set at a rate significantly (at least $3\sigma$) higher than in the null hypothesis of a stationary climate. Except in Antarctica, all-time low records were set at a rate significantly lower than in the null hypothesis. In Europe, North Africa and North Asia the rate of setting new all-time highs increased suddenly in the 1990's, suggesting a change in regional climate regime; in most other regions there was a steadier increase.
... Current models of global climate change have indicated that Southwest Asia (or Middle East) has a high risk of exposure to extreme climatic events (Evans, 2009;Lelieveld et al., 2012). Warming in this region is projected to exceed the thresholds of human tolerance and adaptability (Pal & Eltahir, 2015;Schär, 2016), and aridity is expected to increase across the entire region during the coming decades (Chenoweth et al., 2011). The region has high species diversity, resulting from its crossroad location at the intersection of three biogeographical realms (Palaearctic, Saharo-Arabian and Oriental), but the potential impacts of climate change on its biodiversity remain largely unknown. ...
Aim
The negative impacts of climate change on mammals have been largely based on assessments of total species’ assemblages or individual species at broad scales. Here, we evaluate how the predicted magnitude and velocity of climate change in the arid region of southwest Asia might affect regional functional groups of terrestrial mammals.
Location
Iran.
Methods
We gathered data from 186 species to map diversity hotspots of 12 functional groups, threatened species richness and total species richness. We mapped areas with high risk of exposure to extreme drying and warming events and calculated the velocity of climate change by using precipitation and temperature data from current and future periods. We then quantified the exposure of these hotspots to extreme changes in magnitude and velocity.
Results
Hotspots of functional groups, threatened species and species richness were most exposed to precipitation decline in current and future scenarios (average of 17.9% and 29.9% respectively), compared to temperature rise. While most hotspots are found in mountains, hotspots located in lowlands were more exposed to extreme drying, particularly for carnivore, desert and large-bodied functional groups, as well as threatened species. These patterns remained intact when we considered only hotspots covered by existing protected areas. The impacts of velocity also varied significantly among functional groups, with highest levels for carnivore, large-bodied and specialist groups and threatened species.
Main conclusions
We show that climate change does not equally impact all species within a community and that vulnerability to these changes differed between functional groups. We found that the areas with the highest risk of exposure to extreme climates are located in lowlands and not in mountains. We found that extreme drying, rather than warming, is the major threat to regional mammal diversity in this arid region, particularly for large-bodied and threatened species.
... The use of carbohydrate and amino acid reserves could cause long term metabolic and energetic imbalances, which likely translates into impaired fitness and survival (Alcoverro et al., 2001). Deepgrowing P. oceanica genotypes are, therefore, more fragile in response to extreme heat events, whose intensity and duration are predicted to increase in the coming decades as a result of climate change (Schar, 2016). ...
The endemic Mediterranean seagrass Posidonia oceanica is highly threatened by the increased frequency and intensity of heatwaves. Meadows of the species offer a unique opportunity to unravel mechanisms marine plants activate to cope transient warming, since their wide depth distribution impose divergent heat-tolerance. Understanding these mechanisms is imperative for their conservation. Shallow and deep genotypes within the same population were exposed to a simulated heatwave in mesocosms, to analyze their transcriptomic and photo-physiological responses during and after the exposure. Shallow plants, living in a more unstable thermal environment, optimized phenotype variation in response to warming. These plants showed a pre-adaptation of genes in anticipation of stress. Shallow plants also showed a stronger activation of heat-responsive genes and the exclusive activation of genes involved in epigenetic mechanisms and in molecular mechanisms that are behind their higher photosynthetic stability and respiratory acclimation. Deep plants experienced higher heat-induced damage and activated metabolic processes for obtaining extra energy from sugars and amino acids, likely to support the higher protein turnover induced by heat. In this study we identify transcriptomic mechanisms that may facilitate persistence of seagrasses to anomalous warming events and we discovered that P. oceanica plants from above and below the mean depth of the summer thermocline have differential resilience to heat.
... Anthropogenic emissions have most likely increased (Schär et al. 2004;Meehl and Tebaldi 2004;Wehner et al. 2016). The likelihood of existing heat waves and the predicted potential warming of the atmosphere is proving to increase the incidence of extreme heatwaves (Hayhoe et al. 2010;Jones et al. 2015;Schär 2016). It has made the intense heat waves and is projected to make heat waves even hotter and more frequent in the future (Vose et al. 2017;Diffenbaugh and Scherer 2013). ...
Even though climate change involves much more than warming, it is the name given to a set of physical phenomena. It is a long-term change in weather patterns that characterises different regions of the world. The warming effect in the earth’s atmosphere has dramatically increased through the influence of some heat-taping gases emitted by various human activities, especially fossil fuel burning. The more the input of such gases, the more will be the warming effect in the coming times. Global climate change is already visible in various parts of the larger ecosystems like forests, fisheries, biodiversity, and agriculture; however, it is now also influencing the supply of freshwater, human health, and well-being. This paper reviews climate change drivers, its global scenario, major global events, and assessing climate change impacts. The most daunting problem of economic and ecological risks, along with the threats to humanity, is also discussed. The paper further reviews the species’ vulnerability to climate change and the heat waves and human migration vis-à-vis climate change. Climate change politics and coverage of climate change episodes in mass media is the special focus of this review that concludes with a few mitigation measures.
... The underlying reasons why southwest Asia stands out are discussed by Pal and Eltahir (6), who concluded that future TW max around the Persian/Arabian Gulf region is likely to exceed the TW threshold for human survivability by the end of the century under a business-as-usual (BAU) scenario of atmospheric greenhouse gas (GHG) concentrations. In summer 2015, TW in the Bandar Mahshahr, Iran Persian/Arabian Gulf, reached nearly 35°C, suggesting that the threshold may be breached sooner than projected (7). In this study, we shift our attention to the region of South Asia, here defined as Pakistan, Nepal, India, Bangladesh, and Sri Lanka. ...
The risk associated with any climate change impact reflects intensity of natural hazard and level of human vulnerability. Previous work has shown that a wet-bulb temperature of 35°C can be considered an upper limit on human survivability. On the basis of an ensemble of high-resolution climate change simulations, we project that extremes of wet-bulb temperature in South Asia are likely to approach and, in a few locations, exceed this critical threshold by the late 21st century under the business-as-usual scenario of future greenhouse gas emissions. The most intense hazard from extreme future heat waves is concentrated around densely populated agricultural regions of the Ganges and Indus river basins. Climate change, without mitigation, presents a serious and unique risk in South Asia, a region inhabited by about one-fifth of the global human population, due to an unprecedented combination of severe natural hazard and acute vulnerability.
... and these heatwaves ranked among the most deadly events globally. Anthropogenic emissions have likely increased (Easterling et al 2000, Meehl and Tebaldi 2004, Schär et al 2004, Collins and Knutti 2013, Wehner et al 2016 the probability of current heatwaves, and under the projected future climate warming, the frequency of severe heatwaves is likely to increase further (Meehl and Tebaldi 2004, Hayhoe et al 2010, Lau and Nath 2014, Schär 2016. However, neither the future heatwave hazard over India nor its potential effect on risk to the national human population have yet been quantified for the 1.5 • C and 2.0 • C global temperature limits that feature in current United Nations Framework Convention on Climate discussions (Schellnhuber et al 2016, Schleussner et al 2016, Horowitz 2016). ...
Heatwaves with large impacts have increased in the recent past and will continue to increase
under future warming. However, the implication for population exposure to severe heatwaves
remains unexplored. Here, we characterize maximum potential human exposure (without
passive/active reduction measures) to severe heatwaves in India. We show that if the global
mean temperature is limited to 2.0ºC above pre-industrial conditions, the frequency of severe
heatwaves will rise by 30-times the current climate by the end -21st century. In contrast, the
frequency is projected to be about 2.5 times more (than the low-warming scenario of 2ºC)
under conditions expected if the RCP 8.5 "business-as-usual" emissions scenario is followed.
Under the 2.0ºC low-warming target, population exposure to severe heatwaves is projected
to increase by about 15 and 92-times the current level by the mid and end -21st century
respectively. Strategies to reduce population growth in India during the 21st century may
provide only limited mitigation of heatwave exposure mostly late in the century. Limiting
global temperatures to 1.5°C above preindustrial would reduce the exposure by half relative
to RCP8.5 by the mid-21st century. If global temperatures are to exceed 1.5°C then
substantial measures will be required to offset the large increase in exposure to severe
heatwaves in India.
... These may reduce uterine blood flow, which could affect fetal metabolic responses and trigger contractions, and result in PTB (Dreiling andCarman 1991, Stan et al 2013). It is expected that the frequency, intensity, and duration of heatwaves will increase due to climate change (Schär 2015, Hoegh-Guldberg et al 2018, which will add to the existing PTB burden. Understanding the effect of heatwaves on PTB and identifying optimal thresholds to activate interventions targeting pregnant women is particularly important in the context of climate change. ...
... Climate change will lead to a further increase in the number and intensity of catastrophic weather events such as heat waves, floods, and droughts [1][2][3][4][5]. Of these, flooding is already the most common and destructive of climate-related disaster in many countries, including Canada. ...
Climate change is predicted to increase the frequency and intensity of floods in the province of Quebec, Canada. Therefore, in 2015, to better monitor the level of adaptation to flooding of Quebec residents living in or near a flood-prone area, the Quebec Observatory of Adaptation to Climate Change developed five indices of adaptation to flooding, according to the chronology of events. The present study was conducted 4 years later and is a follow-up to the 2015 one. Two independent samples of 1951 (2015) and 974 (2019) individuals completed a questionnaire on their adoption (or non-adoption) of flood adaptation behaviors, their perception of the mental and physical impacts of flooding, and their knowledge of the fact that they lived in a flood-prone area.
The results of the study demonstrated the measurement invariance of the five indices across two different samples of people over time, ensuring that the differences (or absence of differences) observed in flood-related adaptive behaviors between 2015 and 2019 were real and not due to measurement errors. They also showed that, overall, Quebeckers’ flood-related adaptive behaviors have not changed considerably since 2015, with adaptation scores being similar in 2019 for four of the five flood indices. Moreover, the results indicated an increase in self-reported physical and mental health issues related to past flooding events, as well as a larger proportion of people having consulted a health professional because of these problems. Thus, this study provides a better understanding of flood adaptation in Quebec over the past 4 years and confirms that the five adaptive behavior indices developed in 2015 are appropriate tools for monitoring changes in flood adaptation in the province. Finally, our results showed that little has changed in Quebeckers’ adoption of adaptive behaviors, highlighting the need for awareness raising in order to limit the impacts that climate change will have on the population.
... This slow-growing, millenary seagrass dominates the Mediterranean benthos, and is highly sensitive to a range of anthropogenic threats. How P. oceanica responds to frequent heat waves that increasingly define the new normality of a changed climate (Schar, 2016) will largely determine the continued fate and functioning of this valuable ecosystem and of the entire coastal habitat. Based on observed plant mortalities in natural populations from the Balearic Islands and climate forecast models, gloomy perspectives predicted a major decline of this ecosystem in the coming decades (Jordà et al., 2012). ...
Sexual reproduction in predominantly clonal marine plants increases recombination favoring adaptation and enhancing species resilience to environmental change. Recent studies of the seagrass Posidonia oceanica suggest that flowering intensity and frequency are correlated with warming events associated with global climate change, but these studies have been observational without direct experimental support. We used controlled experiments to test if warming can effectively trigger flowering in P. oceanica. A six-week heat wave was simulated under laboratory mesocosm conditions. Heating negatively impacted leaf growth rates, but by the end of the experiment most of the heated plants flowered, while controls plants did not. Heated and control plants were not genetically distinct and flowering intensity was significantly correlated with allelic richness and heterozygosity. This is an unprecedented finding, showing that the response of seagrasses to warming will be more plastic, more complex and potentially more resilient than previously imagined.
... The current climate in southern Iraq already contains days with temperatures higher than 50 • C [4]. Exposure of humans and other mammals to high temperatures for extended periods would be at risk for life-threatening hyperthermia and dehydration [5]. ...
Fortunately, extreme temperatures reaching 50 °C are not common on our planet. The capability of the consortium for small-scale modelling regional climate model (COSMO-CLM), with 0.44° resolution, to project future trends of an extremely hot environment with direct model output (DMO) is questioned. The temperature distribution of COSMO-CLM output driven by reanalysis and RCP4.5 scenario in southern Iraq was remarkably good, with a slight temperature overestimation, compared to the overlapping observations from Basra airport. An attempt to enhance the DMO with a statistical downscaling method did not improve the results. The COSMO-CLM projection indicates that a very sharp increase in the number of consecutive hours and days with the temperature reaching 50 °C or higher will occur. During 1951–1980, consecutive hours and days reaching 50 °C were rare events. By the end of the century, the projected climate in southern Iraq contains up to 13 consecutive hours and 21 consecutive days reaching 50 °C or higher. As the average projected temperature will increase by ~2 °C compared to the recent climate, new records may be expected. However, the major climate change feature is the increase in consecutive hours and days of very high temperatures. These findings require adaptation measures to support future habitation of the region.
... Wet bulb temperatures approaching 35°C almost never occur in the current climate 32 , and thus there is little real-world data on human health outcomes at the societal level during such extreme conditions. However, recent heat waves with lower wet bulb temperatures between 29°C and 31°C have caused tens of thousands of deaths 5,33 , and empirical evidence suggests that most physical labor becomes unsafe at wet bulb temperatures above 32°C 34,35 . ...
As a result of global increases in both temperature and specific humidity, heat stress is projected to intensify throughout the 21st century. Some of the regions most susceptible to dangerous heat and humidity combinations are also among the most densely populated. Consequently, there is the potential for widespread exposure to wet bulb temperatures that approach and in some cases exceed postulated theoretical limits of human tolerance by mid- to late-century. We project that by 2080 the relative frequency of present-day extreme wet bulb temperature events could rise by a factor of 100–250 (approximately double the frequency change projected for temperature alone) in the tropics and parts of the mid-latitudes, areas which are projected to contain approximately half the world's population. In addition, population exposure to wet bulb temperatures that exceed recent deadly heat waves may increase by a factor of five to ten, with 150–750 million person-days of exposure to wet bulb temperatures above those seen in today's most severe heat waves by 2070–2080. Under RCP 8.5, exposure to wet bulb temperatures above 35 °C—the theoretical limit for human tolerance—could exceed a million person-days per year by 2080. Limiting emissions to follow RCP 4.5 entirely eliminates exposure to that extreme threshold. Some of the most affected regions, especially Northeast India and coastal West Africa, currently have scarce cooling infrastructure, relatively low adaptive capacity, and rapidly growing populations. In the coming decades heat stress may prove to be one of the most widely experienced and directly dangerous aspects of climate change, posing a severe threat to human health, energy infrastructure, and outdoor activities ranging from agricultural production to military training.
The results of monitoring of the climatic and natural conditions of the semidesert in the Dzhanybek station of the Institute of Forest Science of the Russian Academy of Sciences (IFS RAS) in the northern Caspian region are presented. Monitoring studies have been conducted since the middle of the past century. The goal of the observations was to determine the implications of climate change for the habitat, profile, and state of the animated nature of the ecosystem components. In the course of the process, the station’s team observed an increase in the average annual air temperature by 2.2°C and the periodicity in the territory wetness caused by variations in the amount of precipitates. Moreover, in the period of increased wetness from 1980 to 1994, the ground water and water body levels increased, herbaceous communities and cereal crops became more yielding, and wild hoofed animals (saigas) proliferated as well. In the period of drought from 1995 to 2009, the spring melt water runoff attenuated, water bodies shoaled and dried, and dry spells repeated from year to year, which negatively affected the development of the ecosystem components. On the whole, the climate changes have not disturbed the dynamic balanced state of the natural ecosystems (e.g., yield of virgin land phytocenoses, wild animal stock); however, long dry spells have irreversibly aggravated the state of man-made forests and even caused their extinction and long-term cereal crop failures on zonal soils, which has led to unstable agricultural product outputs. The research results reveal the need to switch to adaptive fine-contour or focal farming suited most fitted for the climatic and natural condition of the region.
This study examines the surface air temperature projections and associated uncertainties over the Arabian Peninsula by using data from the Coupled Model Intercomparison Project Phase 5 (CMIP5) under the Representative Concentration Pathways RCP4.5 and RCP8.5 scenarios. The 30-member CMIP5 mean multi-model ensemble (MME) reveals a significant (at the 99% level) increase in temperature by the end of the twenty-first century of around 2.28 (5.53) °C/100 years under the RCP4.5 (RCP8.5) scenarios. The warming as well as the uncertainty associated with the temperature projections over the Arabian Peninsula will increase with time up to the end of the twenty-first century. In the near future (2021–2050), both RCPs (RCP4.5 and RCP8.5) reveal similar increases (~ 2 to 2.5 °C) in temperature compared to the present climate (1976–2005). For the period 2070–2099, the temperatures are projected to be from 2.55 ± 1.58 (4.89 ± 1.58) °C relative to the present climate under RCP4.5 (RCP8.5), while the associated uncertainty ranges from − 1.38 to 5.95 (0.57 to 7.9) °C. Under RCP4.5 (RCP8.5), all models reach 2 °C in the Arabian Peninsula in the twenty-first century relative to 1976–2005 from 2023 (2030) to 2062 (2049). The warming over the Arabian Peninsula is projected to be asymmetric that will vary both spatially and seasonally. A strong increase in the annual mean temperature over the central and northwestern parts of the Arabian Peninsula comes mainly from the summer and autumn season. The projected warming rate is higher in the autumn compared to the other seasons during the twenty-first century. The decadal and centurial warming rates are lower in winter and higher in autumn.
The objective of this paper is to provide a review on some aspects of the mathematical and computational modelling of skin biophysics, with special focus on constitutive theories based on nonlinear continuum mechanics from elasticity, through anelasticity, including growth, to thermoelasticity. Microstructural and phenomenological approaches combining imaging techniques are also discussed. Finally, recent research applications on skin wrinkles will be presented to highlight the potential of physics-based modelling of skin in tackling global challenges such as ageing of the population and the associated skin degradation, diseases and traumas.
Extremes of wet-bulb temperature [WBT] — jointly reflecting temperature and specific humidity — have seen relatively little study in terms of climatology, despite their demonstrated relevance for health and economic impacts. In this study, we uncover and characterize distinct spatiotemporal patterns of WBT extremes in the contiguous United States for the 1981-2015 period, focusing on identifying and making a first pass at understanding regional differences. We find that anomalies of specific humidity are of greater importance than those of temperature in controlling extreme WBT in most of the contiguous U.S., particularly for southern and arid regions. Composites of extreme-WBT days for each region reveal coherent sea-surface temperature and mid- and upper-level geopotential-height anomalies that differ considerably between regions, particularly in terms of the resulting low-level temperature and moisture fields. These findings suggest that the primary factors controlling the timing and intensity of WBT extremes, while ultimately forced by synoptic-scale weather patterns, vary spatially according to both local geography and baseline climate. We demonstrate this conclusion by showing how regional features such as late-summer WBT extremes in the Southwest and southern Great Plains derive primarily from spatial and temporal variations in moist low-level flows.
Climate models' outputs are affected by biases that need to be detected and adjusted to model climate impacts. Many climate hazards and climate-related impacts are associated with the interaction between multiple drivers, i.e. by compound events. So far climate model biases are typically assessed based on the hazard of interest, and it is unclear how much a potential bias in the dependence of the hazard drivers contributes to the overall bias and how the biases in the drivers interact. Here, based on copula theory, we develop a multivariate bias-assessment framework, which allows for disentangling the biases in hazard indicators in terms of the underlying univariate drivers and their statistical dependence. Based on this framework, we dissect biases in fire and heat stress hazards in a suite of global climate models by considering two simplified hazard indicators: the wet-bulb globe temperature (WBGT) and the Chandler burning index (CBI). Both indices solely rely on temperature and relative humidity. The spatial pattern of the hazard indicators is well represented by climate models. However, substantial biases exist in the representation of extreme conditions, especially in the CBI (spatial average of absolute bias: 21 ∘C) due to the biases driven by relative humidity (20 ∘C). Biases in WBGT (1.1 ∘C) are small compared to the biases driven by temperature (1.9 ∘C) and relative humidity (1.4 ∘C), as the two biases compensate for each other. In many regions, also biases related to the statistical dependence (0.85 ∘C) are important for WBGT, which indicates that well-designed physically based multivariate bias adjustment procedures should be considered for hazards and impacts that depend on multiple drivers. The proposed compound-event-oriented evaluation of climate model biases is easily applicable to other hazard types. Furthermore, it can contribute to improved present and future risk assessments through increasing our understanding of the biases' sources in the simulation of climate impacts.
Heatwaves with severe impacts have increased and projected to become more frequent under warming climate in India. Concurrent day and nighttime heatwaves can exacerbate human discomfort causing high morbidity and mortality; however, their changes in the observed and projected climate remain unrecognized. Here using observations and model simulations from climate of 20th century plus (C20C+) detection and attribution (D&A) and coupled model intercomparison project 5 (CMIP5) projects, we show that 1 and 3-day concurrent hot day and hot night (CHDHN) events have significantly increased during the observed climate in India. Our results show that the anthropogenic emissions contribute considerably to the increase of 1 and 3-day CHDHN events in India. The frequency of 3-day CHDHN events is projected to increase 12-fold of the current level by the end of 21st century and 4-fold by the mid 21st century under the high emission pathway of RCP 8.5. The increase in 3-day CHDHN events can be limited to only 2-fold by the end of 21st century under low emission scenario of RCP 2.6. One and 3-day CHDHN events are projected to increase by 4, 6, and 8 folds of the current level in India under the 1.5, 2, and 3 °C warming worlds, respectively. Restricting global mean temperature below 1.5° from the pre-industrial level can substantially reduce the risk of 1 and 3-day CHDHN events and associated implications in India.
In the present study, the quantity, duration and intensity of heat stress events in Germany as well as their future change and relation with weather types were investigated. A small ensemble of regional climate simulations with the regional climate model (RCM) COSMO-CLM driven by four general circulation models (GCMs) was used to calculate the Universal Thermal Climate Index (UTCI); the UTCI is a well-accepted thermal comfort index which we use here to quantify thermal stress. The variables entering the UTCI were bias corrected with a method that preserves their interdependencies. The projected climate changes cause a significant increase of both the mean UTCI and the number, duration and intensity of heat stress events between the control period (1981–2000) and the projection period (2031–2050). The projected future hourly frequency distribution of the UTCI at a location can be described by a shift to higher UTCI values with an almost constant shape of distribution. The investigations of the projected changes in weather types show no significant changes between the periods covered, with a few exceptions. An exception concerning heat stress events is the increase of summer anticyclonic weather types. Although more anticyclonic weather types in summer lead to an increase in heat stress events, they are not the primary cause of the projected increases. Rather, it turns out that the characteristics of the air masses associated with the weather types change towards warmer and more humid conditions.
This article argues that the notion of “global risk” is not appropriate to the state we are about to enter: the Anthropocene. In general, risk requires that the corresponding damage be done only to a limited number of individuals, and that such damage be financially compensable. These are two conditions that can no longer be satisfied with the consequences of crossing the planetary boundaries. The future damage no longer concerns portions of reality, but the very possibility of inhabiting the Earth.
Rapidly ageing populations are coinciding with urbanisation and climate change providing a global challenge. Older people experience higher rates of mortality and morbidity from extreme heat. Climate change is expected to magnify urban heat island effects. Green infrastructure is increasingly recognised as capable of mitigating urban heat and could alleviate some heat burdens on seniors. This research investigated the enablers and barriers to green infrastructure provision in aged care facilities in Australia with senior management from four large national aged care providers. While potential multiple advantages were identified, providers need evidence-based research to justify investment in future green infrastructure interventions.
摘要
人口迅速老龄化的同时，城市化和气候变化也带来了全球性的挑战. 老年人因酷热经历更高的死亡率和发病率. 预计气候变化将放大城市热岛效应. 绿色基础设施越来越被认为能够缓解城市热，并能减轻老年人的一些热负担。这项研究调查了澳大利亚老年护理机构中绿色基础设施提供的促成因素和障碍，他们来自四家大型国家老年护理机构的高级管理人员. 虽然已经确定了潜在的多重优势，但供应商需要基于证据的研究，以证明投资于未来绿色基础设施干预措施的合理性.
We need a modern-day Marshall Plan to build climate resilience in the developing world. It is doable if, for each dollar spent reaching net zero, we spend an additional 25 cents on building resilience.
Prolonged periods of extreme heat also known as heatwaves are a growing concern in a changing climate. Over the Sahel, a hot and semi-arid region in West Africa, they are still relatively poorly understood and managed. In this research, five multivariate thermal indices derived from the ERA5 database were used to characterize Sahelian heatwaves for statistical analysis and as a sampling basis to investigate their underlying thermodynamic causes. Results show that on average most locations in the Sahel suffer from one or two heatwaves a year lasting 3–5 days but with severe magnitude. The eastern Sahel is more at risk than the west, experiencing more frequent and longer lasting events. Despite similar statistics of intensity, duration and frequency across the heatwave indices, for a given diurnal phase, there is surprisingly low agreement in the timing of events. Furthermore daytime and nighttime heatwaves have little synchronicity. In terms of associated thermodynamic processes, heat advection and the greenhouse effect of moisture are identified as the main causes of Sahelian heatwaves. The processes are nevertheless sensitive to the indices, consequence of the distinctness of their respective samples. Therefore attention should be given to the choice of either index in operational monitoring and forecasting of heatwaves. This will allow to effectively target different exposed socio-economic groups and resultantly enhance the efficiency of early warning systems.
Numerous extreme heatwaves producing large impacts on human health, agriculture, water resources, energy demand, regional economies, and forest ecosystems occurred during the first twenty years of the 21st century. The present study strives to provide a systematic review of recent studies of warm biometeorological extremes in Europe. The main aim of this paper is to provide a methodical summary of the observed changes in warm extremes, duration, and variability in different parts of Europe. During the last decade, much attention has been paid to the negative impacts of heat and humidity on human health. Therefore, the human biometeorology is required to appraise the human thermal environment in a way that human thermoregulation is taken into account. In many European countries and regions, future heat exposure will indeed exceed critical levels, and a steep increase in biometeorological heatwaves and warm extremes are expected. The indices that take into account human energy balance along with weather conditions should be used to examine the impacts of extreme heatwaves on human health and should be used as a basis for the determination of acclimatization to high-heat-stress conditions. A detailed description of recent studies that have used biometeorological indices such as Physiological Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI) for the estimation of warm extremes and their influence on human health is provided. Additionally, a short overview of the existence of the heat-health warning systems (HHWS), their conceptualization, and implementation across the European continent is considered, as well as the possibilities for further investigations and implementation of effective measures and programs that could reduce the adverse health impacts.
The classical modeling of spatial extremes relies on asymptotic models (i.e., max‐stable or r‐Pareto processes) for block maxima or peaks over high thresholds, respectively. However, at finite levels, empirical evidence often suggests that such asymptotic models are too rigidly constrained, and that they do not adequately capture the frequent situation where more severe events tend to be spatially more localized. In other words, these asymptotic models have a strong tail dependence that persists at increasingly high levels, while data usually suggest that it should weaken instead. Another well‐known limitation of classical spatial extremes models is that they are either computationally prohibitive to fit in high dimensions, or they need to be fitted using less efficient techniques. In this review paper, we describe recent progress in the modeling and inference for spatial extremes, focusing on new models that have more flexible tail structures that can bridge asymptotic dependence classes, and that are more easily amenable to likelihood‐based inference for large datasets. In particular, we discuss various types of random scale constructions, as well as the conditional spatial extremes model, which have recently been getting increasing attention within the statistics of extremes community. We illustrate some of these new spatial models on two different environmental applications.
This article is categorized under:
• Data: Types and Structure > Image and Spatial Data
• Data: Types and Structure > Time Series, Stochastic Processes, and Functional Data
• Statistical Learning and Exploratory Methods of the Data Sciences > Modeling Methods
Abstract
Classical modeling of spatial extremes relies on asymptotic models for block maxima (max‐stable processes) or threshold exceedances (r‐Pareto processes). These approaches and more flexible subasymptotic models are presented in this paper.
Climate models' outputs are affected by biases that need to be detected and adjusted to model climate impacts. Many climate hazards and climate-related impacts are associated with the interaction between multiple drivers, i.e. by compound events. So far climate model biases are typically assessed based on the hazard of interest, and it is unclear how much a potential bias in the dependence of the hazard drivers contributes to the overall bias and how the biases in the drivers interact. Here, based on copula theory, we develop a multivariate bias assessment framework, which allows for disentangling the biases in hazard indicators in terms of the underlying univariate drivers and their statistical dependence. Based on this framework, we dissect biases in fire and heat stress hazards in a suite of global climate models by considering two simplified hazard indicators, the wet-bulb globe temperature (WBGT) and the Chandler Burning Index (CBI). Both indices solely rely on temperature and relative humidity. The spatial pattern of the hazards indicators is well represented by climate models. However, substantial biases exist in the representation of extreme conditions, especially in the CBI (spatial average of absolute bias: 21 °C) due to the biases driven by relative humidity (20 °C). Biases in WBGT (1.1 °C) are small compared to the biases driven by temperature (1.9 °C) and relative humidity (1.4 °C), as the two biases compensate each other. In many regions, also biases related to the statistical dependence (0.85 °C) are important for WBGT, which indicates that well-designed physically-based multivariate bias adjustment should be considered for hazards and impacts that depend on multiple drivers. The proposed compound event-oriented evaluation of climate model biases is easily applicable to other hazard types. Furthermore, it can contribute to improved present and future risk assessments through increasing our understanding of the biases’ sources in the simulation of climate impacts.
Heatwaves pose a serious threat to human health worldwide but remain poorly documented over Africa. This study uses mainly the ERA5 dataset to investigate their large-scale drivers over the Sahel region during boreal spring, with a focus on the role of tropical modes of variability including the Madden–Julian Oscillation (MJO) and the equatorial Rossby and Kelvin waves. Heatwaves were defined from daily minimum and maximum temperatures using a methodology that retains only intraseasonal scale events of large spatial extent. The results show that tropical modes have a large influence on the occurrence of Sahelian heatwaves, and, to a lesser extent, on their intensity. Depending on their convective phase, they can either increase or inhibit heatwave occurrence, with the MJO being the most important of the investigated drivers. A certain sensitivity to the geographic location and the diurnal cycle is observed, with nighttime heatwaves more impacted by the modes over the eastern Sahel and daytime heatwaves more affected over the western Sahel. The examination of the physical mechanisms shows that the modulation is made possible through the perturbation of regional circulation. Tropical modes thus exert a control on moisture and the subsequent longwave radiation, as well as on the advection of hot air. A detailed case study of a major event, which took place in April 2003, further supports these findings. Given the potential predictability offered by tropical modes at the intraseasonal scale, this study has key implications for heatwave risk management in the Sahel.
Introduction
Climate change is one of the major threats of the 21st century. One of the major data sources for studying climate change is the general circulation model (GCM), which is widely used to assess and project past and future climate change and to manage regional risk hazards. GCMs can make significant assessments of temperature and precipitation. The application of individual models has high uncertainty. Therefore, in this study, applying an ensemble approach has been considered to project future temperature changes in Iran. The purpose of this study is to create a multi-model ensemble (MME) with bias-corrected CMIP6 models to project the temperature of Iran and the warm spell duration index (WSDI) in the near future (2021-2040).
Materials and methods
To evaluate the CMIP6 models in simulating the average annual temperature for the period of 1995 to 2014 (these 20 years were considered as the historical period), we used 120 synoptic stations in Iran. In this study, five CMIP6 models (GFDL-ESM4, MPI-ESM1-2-HR, IPSL-CM6A-LR, MRI-ESM2-0, UKESM1-0-LL) with a horizontal resolution of 0.5 degrees were used. Using intermediate (SSP3-7.0) and worst-case (SSP5-8.5) scenarios, annual temperature and heat stress were projected under climate change conditions for the near future (2040-2021).
In this study, normalized root mean square error (NRMSE) and mean bias error (MBE) were used to validate the performance of the models. To correct the bias of CMIP6 models, Delta change Factor (DCF) method with 120 synoptic station was used. Then, independence weighted mean (IWM), were used to ensemble five models.
In this study, in addition to temperature anomalies, warm spell duration index (WSDI) was also projected by 2040. The warm spell duration index is the number of days per year with at least 6 consecutive days when TX > TX90th, where TX is the daily maximum temperature and TX90th is the calendar day 90th percentile.
Results and discussion
Based on the Direct Model Output (DMO) in the climates of Sea of Oman and Caspian Sea coasts, all five CMIP6 models underestimated the average annual temperature (Chabahar and Rasht stations). However, CMIP6 models in other climates of Iran overestimated the average annual temperature. The mean bias of 1.00, 0.962, 0.983, 1.001, 0.936 degrees Celsius is compute for GFDL-ESM4, IPSL-CM6A-LR, MPI-ESM1-2-HR, MRI-ESM2-0 and UKESM1-0-LL, respectively. Therefore, UKESM1-0-LL and IPSL-CM6A-LR models are efficient models among the studied models for estimating Iran temperature, respectively. The temperature bias values fluctuate from -2.27 to 2.70 degrees Celsius in Iran. The average annual temperature based on MME-CMIP6 output fluctuates between 6.27 and 27.7 degrees Celsius. The coasts of the Persian Gulf and the Sea of Oman showed the maximum temperature and the northwestern regions of Iran showed the minimum temperature. The warm spell duration index varies between 3.48 to 12.5 days during the historical period. The temperature projected for both SSP3-7.0 and SSP5-8.5 scenarios show a further increase in the interior, northwest, north, and northeast of Iran. The average annual anomaly in Iran is estimated to be 1.13 and 1.26 degrees Celsius, based on SSP3-7.0 and SSP5-8.5 scenarios, respectively for the near future during the years 2021-2040.
According to the SSP3-7.0 scenario, the minimum temperature anomaly of the country is 0.765 and the maximum is 1.227 degrees Celsius. Also, for the SSP5-8.5 scenario, temperature anomalies for minimum and maximum annual temperature are estimated to be 0.785 and 1.380 degrees Celsius, respectively. Projecting the time-series changes of the temperature in eight representative stations of Iran under the scenarios of SSP3-7.0 and SSP5-8.5 showed that the amount of warm spell duration varies in different regions of Iran. The anomaly of the warm spell duration index (WSDI) in Iran according to the SSP3-7.0 scenario will increase by at least 13.1 and at most 58.6 days. Also, the results related to the worst-case scenario (SSP5-8.5) have shown a minimum increase of 17.4 days and a maximum of 74.5 days in Iran.
Conclusion
Evaluation of direct output of five models from the series of Coupled Model Intercomparison project (GFDL-ESM4, MPI-ESM1-2-HR, IPSL-CM6A-LR, MRI-ESM2-0, UKESM1-0-LL) In the historical period (1995-2014) showed that although some models performed better in some climate regions of the country, the use of the direct output of individual models will increase the uncertainty in the results. For this purpose, using the independent weighted average (IWM) method, the output of the models was improved. The evaluation of the output of the ensemble model emphasizes this result.
In general, the results of model validation showed that the output of CMIP6 models has higher performance for arid and semi-arid regions of Iran, whether before or after bias-correction. However, using either individual or bias-corrected and ensemble models in very humid climates (The northern parts of Iran) should be used with more caution because even with the correction of bias and doing ensemble, the positive bias is more than 2 degrees Celsius for the mentioned areas.
The projection by using MME-CMIP6 show the annual temperature increase in near future (2021-2040). The average annual temperature anomaly will increase by 1.13 and 1.26 degrees Celsius, under the scenarios of SSP3-7.0 and SSP5-8.5 respectively, during the near future (2021-2040). The results indicate the very important role of unevenness in the heterogeneous distribution of temperature in increasing the average annual temperature of the country in the next two decades. The minimum temperature anomaly is projected in the southeast of Iran and the maximum in the northwestern and central regions.
Projecting the warm spell duration index (WSDI) indicates an increasing anomaly of that in the country. The main hotspot of WSDI is on the southern coast of Iran, especially in the Persian Gulf area, which according to the results of the worst-case scenario will increase by 74.5 days by 2040. Analysis of changes in the average annual temperature of MME-CMIP6 shows that Iran will warm up more rapidly in the near future (2021-2040) than in the historical period (1995-2014). More warming, especially in high and snowy areas, will affect natural ecosystems and limit future access to water resources. Most of the interior, east and south of Iran has arid and semi-arid climate and a sharp rise in temperature under the worst-case scenario (SSP5-8.5) leads to environmental degradation and intensification of drought on the one hand and increased desertification on the other.
Data on the weather conditions and monitoring of vegetation ecosystems in the Northern Caspian semi-desert for the 70-year period were analyzed. A gradual increase in the average air temperature per hydrological year by 2.73ºC (0.039ºC/year) has been revealed. Before and after the 2000s its increase was caused by warming of the cold and warm period of the year, respectively. An increase of the annual atmospheric precipitation in the spring-summer period was detected, mainly in 1978–1995 due to April-June precipitation. The humidification coefficient dynamics allows distinguishing three periods. The first period (1951–1977) is characterized by insignificant fluctuations around the average value (0.30); the second period (1978–1994) is characterized by good moisture, and the third period (1995–2020), on the contrary, – by severe aridity. These climate changes have led to significant transformation of the snow cover formation mechanisms, the surface runoff of spring melt water, and the ground water level. Despite such fluctuations of natural conditions, the annual productivity of virgin vegetation remains in dynamic equilibrium, changing over time in a wave-like manner, with no introduction of heterogeneous species. The protective afforestation has no chance for sustainable development due to warming of the winter months by 2000, which led to the absence of additional moistening of forest crops for a long period due to the deficiency of snow accumulation and surface inflow of spring melt water. The shrinkage of forest stands was intensified by recurrent annual summer atmospheric droughts. The production of agricultural crops was discontinued since the mid-1990s due to their annual failure, as well as the aridity of the growing seasons. The climate warming of the last two decades has brought the landscape of the flat semi-desert territory of the Northern Caspian region ever closer to its original state without agricultural fields and forest plantations. The population of the region is forced to return to extensive cattle breeding, which has existed here since ancient times.
Greenhouse warming poses the main cause of atmospheric hazards' exacerbation and emergence in recent years. Earth planet has been witnessing frequent and severe natural hazards from the distant past; however, global warming has strongly influenced the occurrence of some atmospheric hazards, especially the ones induced by temperature and has increased the frequency and severity of those risks. Such extreme risks arising from temperature element and being affected by global warming could be referred to hot days and their frequency more than one day which undergo heat waves. Of the studies conducted worldwide in conjunction with the phenomenon of heat waves, the following can be pointed out; Sch�r �2�1�� has focused his studies on the �ersian Gulf and the worst heat waves expected in this area. The recent work revealed an upper limit of stability which enables the adaptability of human body with heat stress and humidity. If people are exposed to a combination of temperature and humidity over long periods higher than this level, they will lead to hyperthermia and death, because heat dissipation from the body is physically impossible. �aul and al-Tahrir �2�1�� using a high-resolution regional climate model demonstrated that such a situation can occur much earlier. In Iran, in relation to heat waves, Ghavidel �2�13� analyzed climatic risk of Khuzestan province in 2��� regarding super heat waves using the clustering approach. The obtained results unveiled the establishment of a low pressure at ground level and high pressure dominance at mid-altitudes up to ��� hp as well as the increase in atmosphere thickness having led to the ground overheating. Added to that, the source of heat entering into Khuzestan is advective and hot and dry air transport through Arabian �eninsula, Iraq and Africa. Ghavidel and Rezai �2�14� addressed in a study to determine the temperature-related threshold and analyze the synoptic patterns of super heat temperatures in southeast region of Iran; the results of study approved that the only pattern effective on the occurrence of super heat days in Iran's southeast is the establishment of the Grange's heat low-pressure at ground level and subtropical Azores high elevation dominance at ��� h�a level. In this study, absolute statistical indicators, also recognized as above-threshold values approach, were used in order to identify, classify and heat waves synoptic analysis in the warm
Because of the scarcity of observational data, existing estimates of the heat and water budgets of the Persian Gulf are rather uncertain. This uncertainty leaves open the fundamental question of whether this water body is a net heat source or a net heat sink to the atmosphere. Previous regional modeling studies either used specified surface fluxes to simulate the hydrodynamics of the Gulf or prescribed SST in simulating the regional atmospheric climate; neither of these two approaches is suitable for addressing the above question or for projecting the future climate in this region. For the first time, a high-resolution, two-way, coupled Gulf–atmosphere regional model (GARM) is developed, forced by solar radiation and constrained by observed lateral boundary conditions, suited for the study of current and future climates of the Persian Gulf. Here, this study demonstrates the unique capability of this model in consistently predicting surface heat and water fluxes and lateral heat and water exchanges with the Arabian Sea, as well as the variability of water temperature and water mass. Although these variables are strongly coupled, only SST has been directly and sufficiently observed. The coupled model succeeds in simulating the water and heat budgets of the Persian Gulf without any artificial flux adjustment, as demonstrated in the close agreement of model simulation with satellite and in situ observations.
The coupled regional climate model simulates a net surface heat flux of +3 W m[superscript −2], suggesting a small net heat flux from the atmosphere into the Persian Gulf. The annual evaporation from the Persian Gulf is 1.84 m yr[superscript −1], and the annual influx and outflux of water through the Strait of Hormuz between the Persian Gulf and Arabian Sea are equivalent to Persian Gulf–averaged precipitation and evaporation rates of 33.7 and 32.1 m yr[superscript −1], with a net influx of water equivalent to a Persian Gulf–averaged precipitation rate of 1.6 m yr[superscript −1]. The average depth of the Persian Gulf water is ~38 m. Hence, it suggests that the mean residency time scale for the entire Persian Gulf is ~14 months.
This study was motivated by two main concerns including (a) prediction of the Persian Gulf Sea surface temperature (PGSST) anomalies using an autoregressive integrated moving average (ARIMA) model and (b) detection of the climate change signatures in the considered SST data. An ARIMA model was, therefore, developed to predict the SST anomalies having lead times from 1 to 3 months. While the SST time series for the period of 1950-2006 used to fit the model, corresponding records for January 2007 to June 2011 were applied as the test data. The developed model had a minimum value of Akaike information criterion, and its parameters were significantly different from zero. The correlation coefficients between the observed and simulated data for the lead times of 1, 2, and 3 months were found to be significant and equal to 0.72, 0.69, and 0.65, respectively. The corresponding hit rates were estimated as 79, 75, and 72 %, indicating a reasonable forecasting capability of the model. The Heidke’s forecast scores were 0.59, 0.52, and 0.48 for the prediction schemes having 1, 2, and 3 months of lead time, respectively. It is shown that the Persian Gulf skin temperatures have warmed up about 0.57 °C during the 732 successive months of the period 1950-2010 noted as an upward significant trend. Although a significant trend was not evident for the 1950-1969 and 1970-1989 period, the PGSST has abruptly increased during the recent two decades. Almost all of the observed warming in the PGSST data is related to this period.
The summer of 2010 was exceptionally warm in eastern Europe and large parts of Russia. We provide evidence that the anomalous
2010 warmth that caused adverse impacts exceeded the amplitude and spatial extent of the previous hottest summer of 2003.
“Mega-heatwaves” such as the 2003 and 2010 events likely broke the 500-year-long seasonal temperature records over approximately
50% of Europe. According to regional multi-model experiments, the probability of a summer experiencing mega-heatwaves will
increase by a factor of 5 to 10 within the next 40 years. However, the magnitude of the 2010 event was so extreme that despite
this increase, the likelihood of an analog over the same region remains fairly low until the second half of the 21st century.
Daily numbers of deaths at a regional level were collected in 16 European countries. Summer mortality was analyzed for the reference period 1998-2002 and for 2003. More than 70,000 additional deaths occurred in Europe during the summer 2003. Major distortions occurred in the age distribution of the deaths, but no harvesting effect was observed in the months following August 2003. Global warming constitutes a new health threat in an aged Europe that may be difficult to detect at the country level, depending on its size. Centralizing the count of daily deaths on an operational geographical scale constitutes a priority for Public Health in Europe.
A human body may be able to adapt to extremes of dry-bulb temperature (commonly referred to as simply temperature) through perspiration and associated evaporative cooling provided that the wet-bulb temperature (a combined measure of temperature and humidity or degree of "mugginess") remains below a threshold of 35 °C. (ref.). This threshold defines a limit of survivability for a fit human under well-ventilated outdoor conditions and is lower for most people. We project using an ensemble of high-resolution regional climate model simulations that extremes of wet-bulb temperature in the region around the Arabian Gulf are likely to approach and exceed this critical threshold under the business-as-usual scenario of future greenhouse gas concentrations. Our results expose a specific regional hotspot where climate change, in the absence of significant mitigation, is likely to severely impact human habitability in the future.
The short but intense heat wave in mid-July 1995 caused 830 deaths
nationally, with 525 of these deaths in Chicago. Many of the dead were
elderly. and the event raised great concern over why it happened.
Assessment of causes for the heat wave-related deaths in Chicago
revealed many factors were at fault, including an inadequate local heat
wave warning system, power failures, questionable death assessments,
inadequate ambulance service and hospital facilities, the heat island,
an aging population, and the inability of many persons to properly
ventilate their residences due to fear of crime or a lack of resources
for fans or air conditioning. Heat-related deaths appear to be on the
increase in the United States. Heat-related deaths greatly exceed those
caused by other life-threatening weather conditions. Analysis of the
impacts and responses to this heat wave reveals a need to 1) define the
heat island conditions during heat waves for all major cities is a means
to improve forecasts of threatening conditions, 2) develop a nationally
uniform means for classifying heat-related deaths, 3) improve warning
systems that are designed around local conditions of large cities, and
4) increase research on the meteorological and climatological aspects of
heat stress and heat waves.
Despite the uncertainty in future climate-change impacts, it is often assumed that humans would be able to adapt to any possible warming. Here we argue that heat stress imposes a robust upper limit to such adaptation. Peak heat stress, quantified by the wet-bulb temperature T(W), is surprisingly similar across diverse climates today. T(W) never exceeds 31 degrees C. Any exceedence of 35 degrees C for extended periods should induce hyperthermia in humans and other mammals, as dissipation of metabolic heat becomes impossible. While this never happens now, it would begin to occur with global-mean warming of about 7 degrees C, calling the habitability of some regions into question. With 11-12 degrees C warming, such regions would spread to encompass the majority of the human population as currently distributed. Eventual warmings of 12 degrees C are possible from fossil fuel burning. One implication is that recent estimates of the costs of unmitigated climate change are too low unless the range of possible warming can somehow be narrowed. Heat stress also may help explain trends in the mammalian fossil record.
Climate Change 2013: The Physical Science Basis
- G. J. Van Oldenborgh