Response of Urban Heat Stress to Heat Waves in Athens (1960–2017)

The increasing frequency, intensity and duration of heat waves seem to follow the observed global warming in recent decades. Vulnerability to heat waves is expected to increase in urban environments mainly due to population density and the effect of the urban heat island that make cities hotter than surrounding non-urban areas. The present study focuses on a vulnerable area of the eastern Mediterranean, already characterized as a ‘hot spot’ with respect to heat-related risk and investigates the change in heat stress levels during heat wave compared to non-heat wave conditions as well as the way that heat stress levels respond to heat waves in urban, compared to non-urban, environments. The adoption of a metric accounting for both the intensity and duration of the hot event yielded a total of 46 heat wave episodes over a nearly 60-year period, but with very rare occurrence until the late 1990s and a profound increased frequency thereafter. The results reveal a difference of at least one thermal stress category between heat wave and non-heat wave periods, which is apparent across the entire range of the thermal stress distribution. The analysis demonstrates a robust intensification of nighttime heat stress conditions in urban, compared to non-urban, sites during severe heat waves. Nevertheless, severe heat waves almost equalize heat stress conditions between urban and non-urban sites during midday.

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O8B.6 Occupational heat stress due to climate change: estimating future heat wave hazards

Occupational and Environmental Medicine ◽

10.1136/oem-2019-epi.197 ◽

2019 ◽

Vol 76 (Suppl 1) ◽

pp. A73.2-A73

Author(s):

Matthias Otto ◽

Tord Kjellstrom ◽

Bruno Lemke

Keyword(s):

Climate Change ◽

Heat Stress ◽

Occupational Health ◽

Health Effects ◽

Heat Wave ◽

Climate Models ◽

Heat Waves ◽

Grid Cell ◽

High Heat ◽

Temperate Climate

Exposure to extreme heat negatively affects occupational health. Heat stress indices like Wet Bulb Globe Temperature (WBGT) combine temperature and humidity and allow quantifying the climatic impact on human physiology and clinical health. Multi-day periods of high heat stress (aka. heat waves) affect occupational health and productivity independently from the absolute temperature levels; e.g. well-documented heat-waves in Europe caused disruption, hospitalisations and deaths (2003 French heat wave: more than 1000 extra deaths, 15–65 years, mainly men) even though the temperatures were within the normal range of hotter countries.Climate change is likely to increase frequency and severity of periods of high heat stress. However, current global grid-cell based climate models are not designed to predict heat waves, neither in terms of severity or frequency.By analysing 37 years of historic daily heat index data from almost 5000 global weather stations and comparing them to widely used grid-cell based climate model outputs over the same period, our research explores methods to assess the frequency and intensity of heat waves as well as the associated occupational health effects at any location around the world in the future.Weather station temperature extreme values (WBGT) for the 3 hottest days in 30 years exceed the mean WBGT of the hottest month calculated from climate models in the same grid-cell by about 2 degrees in the tropics but by 10 degrees at higher latitudes in temperate climate regions.Our model based on the relationship between actual recorded periods of elevated heat-stress and grid-cell based climate projections, in combination with population and employment projections, can quantify national and regional productivity loss and health effects with greater certainty than is currently the case.

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Verification of Heat Stress Thresholds for a Health-Based Heat-Wave Definition

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-18-0246.1 ◽

2019 ◽

Vol 58 (6) ◽

pp. 1177-1194 ◽

Cited By ~ 11

Author(s):

Claudia Di Napoli ◽

Florian Pappenberger ◽

Hannah L. Cloke

Keyword(s):

Heat Stress ◽

Thermal Stress ◽

Excess Mortality ◽

Heat Waves ◽

Warning System ◽

High Heat ◽

Probability Of Detection ◽

Climate Index ◽

Test Bed ◽

Maximum Heat

AbstractHeat waves represent a threat to human health and excess mortality is one of the associated negative effects. A health-based definition for heat waves is therefore relevant, especially for early warning purposes, and it is here investigated via the universal thermal climate index (UTCI). The UTCI is a bioclimate index elaborated via an advanced model of human thermoregulation that estimates the thermal stress induced by air temperature, wind speed, moisture, and radiation on the human physiology. Using France as a test bed, the UTCI was computed from meteorological reanalysis data to assess the thermal stress conditions associated with heat-attributable excess mortality in five cities. UTCI values at different climatological percentiles were defined and evaluated in their ability to identify periods of excess mortality (PEMs) over 24 years. Using verification metrics such as the probability of detection (POD), the false alarm ratio (FAR), and the frequency bias (FB), daily minimum and maximum heat stress levels equal to or above corresponding UTCI 95th percentiles (15° ± 2°C and 34.5° ± 1.5°C, respectively) for 3 consecutive days are demonstrated to correlate to PEMs with the highest sensitivity and specificity (0.69 ≤ POD ≤ 1, 0.19 ≤ FAR ≤ 0.46, 1 ≤ FB ≤ 1.48) than minimum, maximum, and mean heat stress level singularly and other bioclimatological percentiles. This finding confirms the detrimental effect of prolonged, unusually high heat stress at day- and nighttime and suggests the UTCI 95th percentile as a health-meaningful threshold for a potential heat-health watch warning system.

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Can climate adaptation solutions fix the urban heat island? An assessment of the thermal conditions during heat waves in Vienna impacted by climate change and urban development scenarios for the mid-21st-century

10.5194/egusphere-egu2020-8668 ◽

2020 ◽

Author(s):

Paul Hamer ◽

Heidelinde Trimmel ◽

Philipp Weihs ◽

Stéphanie Faroux ◽

Herbert Formayer ◽

...

Keyword(s):

Climate Change ◽

Urban Heat Island ◽

Heat Wave ◽

Air Temperature ◽

Urban Areas ◽

Climate Adaptation ◽

Heat Waves ◽

Heat Island ◽

Human Thermal Comfort ◽

Urban Heat

Climate change threatens to exacerbate existing problems in urban areas arising from the urban heat island. Furthermore, expansion of urban areas and rising urban populations will increase the numbers of people exposed to hazards in these vulnerable areas. We therefore urgently need study of these environments and in-depth assessment of potential climate adaptation measures.We present a study of heat wave impacts across the urban landscape of Vienna for different future development pathways and for both present and future climatic conditions. We have created two different urban development scenarios that estimate potential urban sprawl and optimized development concerning future building construction in Vienna and have built a digital representation of each within the Town Energy Balance (TEB) urban surface model. In addition, we select two heat waves of similar frequency of return representative for present and future conditions (following the RCP8.5 scenario) of the mid 21st century and use the Weather Research and Forecasting Model (WRF) to simulate both heat wave events. We then couple the two representations urban Vienna in TEB with the WRF heat wave simulations to estimate air temperature, surface temperatures and human thermal comfort during the heat waves. We then identify and apply a set of adaptation measures within TEB to try to identify potential solutions to the problems associated with the urban heat island.Global and regional climate change under the RCP8.5 scenario causes the future heat wave to be more severe showing an increase of daily maximum air temperature in Vienna by 7 K; the daily minimum air temperature will increase by 2-4 K. We find that changes caused by urban growth or densification mainly affect air temperature and human thermal comfort local to where new urbanisation takes place and does not occur significantly in the existing central districts.Exploring adaptation solutions, we find that a combination of near zero-energy standards and increasing albedo of building materials on the city scale accomplishes a maximum reduction of urban canyon temperature of 0.9 K for the minima and 0.2 K for the maxima. Local scale changes of different adaption measures show that insulation of buildings alone increases the maximum wall surface temperatures by more than 10 K or the maximum mean radiant temperature (MRT) in the canyon by 5 K.&#160; Therefore, additional adaptation to reduce MRT within the urban canyons like tree shade are needed to complement the proposed measures.This study concludes that the rising air temperatures expected by climate change puts an unprecedented heat burden on Viennese inhabitants, which cannot easily be reduced by measures concerning buildings within the city itself. Additionally, measures such as planting trees to provide shade, regional water sensitive planning and global reduction of greenhouse gas emissions in order to reduce temperature extremes are required.We are now actively seeking to apply this set of tools to a wider set of cases in order to try to find effective solutions to projected warming resulting from climate change in urban areas.

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Heat and dehydration induced oxidative damage and antioxidant defenses following incubator heat stress and a simulated heat wave in wild caught four-striped field mice Rhabdomys dilectus

PLoS ONE ◽

10.1371/journal.pone.0242279 ◽

2020 ◽

Vol 15 (11) ◽

pp. e0242279

Author(s):

Paul J. Jacobs ◽

M. K. Oosthuizen ◽

C. Mitchell ◽

Jonathan D. Blount ◽

Nigel C. Bennett

Keyword(s):

Oxidative Stress ◽

Lipid Peroxidation ◽

Heat Stress ◽

Oxidative Damage ◽

Heat Wave ◽

Body Mass ◽

Heat Waves ◽

Heat Exposure ◽

Field Mice ◽

The Brain

Heat waves are known for their disastrous mass die-off effects due to dehydration and cell damage, but little is known about the non-lethal consequences of surviving severe heat exposure. Severe heat exposure can cause oxidative stress which can have negative consequences on animal cognition, reproduction and life expectancy. We investigated the current oxidative stress experienced by a mesic mouse species, the four striped field mouse, Rhabdomys dilectus through a heat wave simulation with ad lib water and a more severe temperature exposure with minimal water. Wild four striped field mice were caught between 2017 and 2019. We predicted that wild four striped field mice in the heat wave simulation would show less susceptibility to oxidative stress as compared to a more severe heat stress which is likely to occur in the future. Oxidative stress was determined in the liver, kidney and brain using malondialdehyde (MDA) and protein carbonyl (PC) as markers for oxidative damage, and superoxide dismutase (SOD) and total antioxidant capacity (TAC) as markers of antioxidant defense. Incubator heat stress was brought about by increasing the body temperatures of animals to 39–40.8°C for 6 hours. A heat wave (one hot day, followed by a 3-day heatwave) was simulated by using temperature cycle that wild four striped field mice would experience in their local habitat (determined through weather station data using temperature and humidity), with maximal ambient temperature of 39°C. The liver and kidney demonstrated no changes in the simulated heat wave, but the liver had significantly higher SOD activity and the kidney had significantly higher lipid peroxidation in the incubator experiment. Dehydration significantly contributed to the increase of these markers, as is evident from the decrease in body mass after the experiment. The brain only showed significantly higher lipid peroxidation following the simulated heat wave with no significant changes following the incubator experiment. The significant increase in lipid peroxidation was not correlated to body mass after the experiment. The magnitude and duration of heat stress, in conjunction with dehydration, played a critical role in the oxidative stress experienced by each tissue, with the results demonstrating the importance of measuring multiple tissues to determine the physiological state of an animal. Current heat waves in this species have the potential of causing oxidative stress in the brain with future heat waves to possibly stress the kidney and liver depending on the hydration state of animals.

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Trends in heat stress over Europe over the 20th century

10.5194/egusphere-egu21-2582 ◽

2021 ◽

Author(s):

Joakim Kjellsson ◽

Nils Niebaum ◽

Robin Pilch Kedzierski

Keyword(s):

Heat Stress ◽

20Th Century ◽

Heat Wave ◽

Air Temperature ◽

Heat Waves ◽

Dew Point ◽

Stress Index ◽

Internal Climate Variability ◽

Air Temperatures ◽

Using Data

We investigate how European heat waves and their associated heat stress on humans have changed over the 20th century. We find that the heat stress has increased, even in regions where heat waves have not become warmer. As heat stress increases over wide areas of Europe there is also an increase in the total population affected by the heat stress.&#160;Heat waves pose a serious health risk to humans by reducing our ability to shed heat. We have studied the occurrence and intensity of heat waves as well as a heat stress index based on simplified wet-bulb globe temperature using data from ERA-20C reanalysis 1900-2010. Over the 110 years of data we find an overall warming of the air temperatures and dew point. The 98th percentile of both air temperature has increased by more than 1.5&#176;C over large areas of Europe.&#160;We find an overall increase in heat wave days per year as well as an increase of air temperature during heat waves over most of Europe. As such, many densely populated areas exhibit increased heat stress during heat waves. For example, the mean heat stress during heat wave days over Paris has increased by one level, from &#8220;alert&#8221; in 1900-1930 to &#8220;caution&#8221; in 1980-2010. The fraction of the population exposed to heat waves has increased by 10%/century in central Europe and 25%/century over the Mediterranean.&#160;We find more heat waves during 1920 - 1950, which may be related to the positive phase of the Atlantic Multidecadal Variation (AMV). This suggests that the heat stress during European heat waves may also be influenced by internal climate variability, and large-ensemble model simulations may be used to disentangle the effects of natural variability and anthropogenic forcing.

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Analysis of Urban Heat Island and Heat Waves Using Sentinel-3 Images: a Study of Andalusian Cities in Spain

Earth Systems and Environment ◽

10.1007/s41748-021-00268-9 ◽

2021 ◽

Author(s):

David Hidalgo García

Keyword(s):

Solar Radiation ◽

Urban Heat Island ◽

Heat Wave ◽

Land Surface ◽

Heat Waves ◽

Economic Cost ◽

Heat Island ◽

Multivariate Relationships ◽

Urban Heat ◽

Wave Conditions

Abstract At present, understanding the synergies between the Surface Urban Heat Island (SUHI) phenomenon and extreme climatic events entailing high mortality, i.e., heat waves, is a great challenge that must be faced to improve the quality of life in urban zones. The implementation of new mitigation and resilience measures in cities would serve to lessen the effects of heat waves and the economic cost they entail. In this research, the Land Surface Temperature (LST) and the SUHI were determined through Sentinel-3A and 3B images of the eight capitals of Andalusia (southern Spain) during the months of July and August of years 2019 and 2020. The objective was to determine possible synergies or interaction between the LST and SUHI, as well as between SUHI and heat waves, in a region classified as highly vulnerable to the effects of climate change. For each Andalusian city, the atmospheric variables of ambient temperature, solar radiation, wind speed and direction were obtained from stations of the Spanish State Meteorological Agency (AEMET); the data were quantified and classified both in periods of normal environmental conditions and during heat waves. By means of Data Panel statistical analysis, the multivariate relationships were derived, determining which ones statistically influence the SUHI during heat wave periods. The results indicate that the LST and the mean SUHI obtained are statistically interacted and intensify under heat wave conditions. The greatest increases in daytime temperatures were seen for Sentinel-3A in cities by the coast (LST = 3.90 °C, SUHI = 1.44 °C) and for Sentinel-3B in cities located inland (LST = 2.85 °C, SUHI = 0.52 °C). The existence of statistically significant positive relationships above 99% (p < 0.000) between the SUHI and solar radiation, and between the SUHI and the direction of the wind, intensified in periods of heat wave, could be verified. An increase in the urban area affected by the SUHI under heat wave conditions is reported. Graphical Abstract

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Understanding and Analysing the Urban Heat Island (UHI) Effect in Micro-Scale

International Journal of Social Ecology and Sustainable Development ◽

10.4018/ijsesd.2019040102 ◽

2019 ◽

Vol 10 (2) ◽

pp. 14-28 ◽

Cited By ~ 2

Author(s):

Ali Soltani ◽

Ehsan Sharifi

Keyword(s):

Heat Stress ◽

Surface Temperature ◽

Urban Heat Island ◽

Metropolitan Area ◽

Urban Environments ◽

Heat Island ◽

Late Afternoon ◽

Micro Scale ◽

Daily Cycles ◽

Urban Heat

The shortage of vegetation cover alongside urban structures and land hardscape in cities causes an artificial temperature increase in urban environments known as the urban heat island (UHI) effect. The artificial heat stress in cities has a particular threat for usability and health-safety of outdoor living in public space. Australia may face a likely 3.8°C increase in surface temperature by 2090. Such an increase in temperature will have a severe impact on regional and local climate systems, natural ecosystems, and human life in cities. This paper aims to determine the patterns of the UHI effect in micro-scale of Adelaide metropolitan area, South Australia. The urban near-surface temperature profile of Adelaide was measured along a linear east-west cross-section of the metropolitan area via mobile traverse method between 26 July 2013 and 15 August 2013. Results indicate that the while the maximum UHI effect occurs at midnight in the central business district (CBD) area in Adelaide, the afternoon urban warmth has more temperature variations (point-to-point variation), especially during the late afternoon when local air temperature is normally in its peak. Thus, critical measurement of heat-health consequences of the UHI effect need to be focused on the afternoon heat stress conditions in UHIs rather than the commonly known night time phenomenon. This mobile traverse urban heat study of Adelaide supports the hypothesis that the UHI effect varies in the built environment during daily cycles and within short distances. Classical UHI measurements are commonly performed during the night – when the urban-rural temperature differences are at their maximum. Thus, they fall short in addressing the issue of excess heat stress on human participants. However, having thermally comfortable urban microclimates is a fundamental characteristic of healthy and vibrant public spaces. Therefore, urban planning professionals and decision makers are required to consider diurnal heat stress alongside nocturnal urban heat islands in planning healthy cities. The results of this article show that the diurnal heat stress varies in the built environment during daily cycles and within short distances. This study confirms that the maximum urban heat stress occurs during late afternoon when both overall temperature and daily urban warmth are at their peak. Literature indicates that diurnal heat stress peaks in hard-landscapes urban settings while it may decrease in urban parklands and near water bodies. Therefore, urban greenery and surface water can assist achieving more liveable and healthy urban environments (generalisation requires further research). A better understanding of daily urban warmth variations in cities assists urban policy making and public life management in the context of climate change.

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Differential Regulation by Heat Stress of Novel Cytochrome P450 Genes from the Dinoflagellate Symbionts of Reef-Building Corals

Applied and Environmental Microbiology ◽

10.1128/aem.02984-09 ◽

2010 ◽

Vol 76 (9) ◽

pp. 2823-2829 ◽

Cited By ~ 30

Author(s):

Nedeljka N. Rosic ◽

Mathieu Pernice ◽

Simon Dunn ◽

Sophie Dove ◽

Ove Hoegh-Guldberg

Keyword(s):

Cytochrome P450 ◽

Heat Stress ◽

Thermal Stress ◽

Elevated Temperatures ◽

Fold Increase ◽

Transcript Abundance ◽

Stress Conditions ◽

Cytochrome P450 Monooxygenases ◽

Gene Transcript ◽

Mrna Pool

ABSTRACT Exposure to heat stress has been recognized as one of the major factors leading to the breakdown of the coral-alga symbiosis and coral bleaching. Here, we describe the presence of three new cytochrome P450 (CYP) genes from the reef-building coral endosymbiont Symbiodinium (type C3) and changes in their expression during exposure to severe and moderate heat stress conditions. Sequence analysis of the CYP C-terminal region and two conserved domains, the “PERF” and “heme-binding” domains, confirmed the separate identities of the CYP genes analyzed. In order to explore the effects of different heat stress scenarios, samples of the scleractinian coral Acropora millepora were exposed to elevated temperatures incrementally over an 18-h period (rapid thermal stress) and over a 120-h period (gradual thermal stress). After 18 h of gradual heating and incubation at 26°C, the Symbiodinium CYP mRNA pool was approximately 30% larger, while a further 6°C increase to a temperature above the average sea temperature (29°C after 72 h) resulted in a 2- to 4-fold increase in CYP expression. Both rapid heat stress and gradual heat stress at 32°C resulted in 50% to 90% decreases in CYP gene transcript abundance. Consequently, the initial upregulation of expression of CYP genes at moderately elevated temperatures (26°C and 29°C) was followed by a decrease in expression under the greater thermal stress conditions at 32°C. These findings indicate that in the coral-alga symbiosis under heat stress conditions there is production of chemical stressors and/or transcriptional factors that regulate the expression of genes, such as the genes encoding cytochrome P450 monooxygenases, that are involved in the first line of an organism's chemical defense.

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The Effect of Foliar Putrescine Application, Ammonium Exposure, and Heat Stress on Antioxidant Compounds in Cauliflower Waste

Antioxidants ◽

10.3390/antiox10050707 ◽

2021 ◽

Vol 10 (5) ◽

pp. 707

Author(s):

Jacinta Collado-González ◽

Maria Carmen Piñero ◽

Ginés Otálora ◽

Josefa López-Marín ◽

Francisco M. del Amor

Keyword(s):

Heat Stress ◽

Thermal Stress ◽

Heat Waves ◽

Foliar Application ◽

Pharmaceutical Preparations ◽

Point Of View ◽

Total Phenolic ◽

Antioxidant Compounds ◽

Short Term ◽

Heat Effects

This work has been focused on the study of how we can affect the short heat stress on the bioactive compounds content. Some recent investigations have observed that management of nitrogen fertilization can alleviate short-term heat effects on plants. Additionally, the short-term heat stress can be also ameliorated by using putrescine, a polyamine, due to its crucial role in the adaptation of plants to heat stress Therefore, different NO3−/NH4+ ratios and a foliar putrescine treatment have been used in order to increase tolerance to thermal stress in order to take advantage of the more frequent and intense heat waves and make this crop more sustainable. So, other objective of this work is to make the cauliflower waste more attractive for nutraceutical and pharmaceutical preparations. Thus, the effect of a thermal stress combined with a 50:50 NO3−/NH4+ ratio in the nutrient solution, and the foliar application of 2.5 mM putrescine increased in the content of various sugars (inositol, glucose, and fructose), total phenolic compounds and polyamines, as well as in the antioxidant activity. The greatest accumulation of these compounds was observed in young leaves. Our results show from a physiological and agronomic point of view, that the foliar application of putrescine and the 50:50 NO3−/NH4+ treatment managed to alleviate the negative effects of the abiotic stress suffered at high temperature, yielding plants with higher antioxidant compounds content.

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Artificial heat waves induce species-specific plastic responses on reproduction of two spider mite predators

Journal of Pest Science ◽

10.1007/s10340-021-01459-z ◽

2021 ◽

Author(s):

A. Walzer ◽

T. Steiner ◽

B. Spangl ◽

E. Koschier

Keyword(s):

Heat Stress ◽

Heat Wave ◽

Spider Mite ◽

Heat Waves ◽

Phytoseiulus Persimilis ◽

Biocontrol Agents ◽

Egg Number ◽

Wave Conditions ◽

Species Specific ◽

Artificial Heat

AbstractClimate change models predict that the frequency, intensity and duration of heat waves will increase in the next decades. Heat waves can have profound impact on the reproduction of biocontrol agents ranging from postponing oviposition to manipulating offspring quantity via egg number and quality via egg size. Such species-specific responses of biocontrol agents to heat stress may also affect their success in controlling the target pest. Here, we evaluated the predation and reproductive performance of the two spider mite predators Phytoseiulus persimilis and Neoseiulus womersleyi exposed to simulated mild, moderate and extreme heat wave conditions over three days. Irrespective of heat wave conditions, all N. womersleyi females survived, whereas 12% of the P. persimilis females died. Both species responded to heat stress via plastic modifications resulting in increased predation rates and smaller egg sizes. Significantly more P. persimilis females postponed oviposition during the experimental phase than N. womersleyi. The deposited egg number of Phytoseiulus persimilis was not affected by heat wave conditions. On the contrary, the reproductive output of N. womersleyi was a function of temperature, i.e., the higher the temperature, the higher the number of deposited eggs. These findings indicate that P. persimilis is more heat sensitive in relation to reproduction than N. womersleyi. However, further investigations of heat wave effects on other fitness-related traits and their consequences at population level are needed to find out whether N. womersleyi is an alternative or supplement to P. persimilis as spider mite control agent under heat waves.

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