With no universal criteria for classifying a heat-related death, the scope and magnitude of heat-related illnesses and deaths is underestimated. By using threshold temperatures based on one and two standard deviations from normal, a unique but universal classification for excessive/extreme heat was calculated. These threshold values were calculated for St. Louis, Missouri; New Orleans, Louisiana; Little Rock, Arkansas; Philadelphia, Pennsylvania; and Milwaukee, Wisconsin for June, July, and August from 1990 ? 1999. Statistical analysis was performed for each city on days with excessive/extreme maximum and/or minimum temperature values, death count, and death count one, two, and three days later in order to discover a possible strong and significant relationship between excessive/extreme heat and death.

Background: Climate change has increased the frequency, intensity, duration, and spatial extent of some extreme weather events, for instance heat waves. Societies today are experiencing an ongoing change in the population structure yielding an increasing proportion elderly due to increased longevity, resulting in higher prevalence of chronic and degenerative diseases. Literature suggests that the elderly and certain susceptible subgroups with chronic disease are among the most vulnerable to heat waves and elevated temperatures. Aim: The main aims of this thesis were to expand the scientific knowledge on the short-term effects of extreme heat on mortality for the general population and certain susceptible groups in society, to investigate the development of this relationship over time and to attribute mortality to observed climate change. Methods: Daily numbers of deaths and daily meteorological observations during three different periods were collected for present day Stockholm County, Sweden. The analyses of the relationship between mortality and temperature extremes were analysed using a time series approach. The regression models assumed the daily counts of mortality to follow an overdispersed Poisson distribution and adjustments were made for time-trends as well as confounding factors. Results: The literature review of recent studies identified a strong relationship between heat and heat waves and increasing death rates among the elderly, particularly for respiratory and cardiovascular mortality. A statistically significant increase in total daily mortality during heat extremes in all decades investigated, as well as over the entire period, during the period 1901-2009 with a declining trend over time for the relative risk associated with heat extremes, was reported in paper II. For the period 1901-2009 cold extremes significantly increased mortality, with a more disperse pattern over individual decades and no declining trend over time. Paper III attributed increased mortality due to climate change between 1900-1929 and 1980-2009. This increase was mainly due to a large number of excess heat extremes in the latter time period. Furthermore certain subgroups of the population above 50, were in paper IV found to have significantly increased mortality during heat waves as compared to non-heat wave days. Conclusions: Although the relative risk of dying during extreme temperature events appears to have fallen in Stockholm, Sweden, such events still pose a threat to public health. The elderly population and certain susceptible subgroups of the population experience higher relative risks of dying on heat waves days as compared to normal summer days. Some of the groups most susceptible during heat waves were identified. In order to minimize future impacts of heat waves on public health, identifying susceptible subgroups in an ageing society as well as develop strategies to reduce the impact of future temperature extremes on public health will be important.

Four different heat wave definitions (as outlined by Hajat et al, 2006; D’lppoliti et al, 2010; Anderson and Bell, 2011; Nairn and Fawcett, 2013) were used to characterize heat wave mortality across the United States. The goal was to identify if certain definitions perform better or worse than others. Overall every definition performed poorly, resulting in high False-Alarm Ratios and low Heidke Skill Scores. However, the Nairn and Fawcett (2013) and Anderson and Bell (2011) definitions performed consistently better than the other definitions. Despite several limitations, the results of this study indicate that the heat wave definitions need refinement. Additionally, the Nairn and Fawcett (2013) definition could be one of the best definitions for assessing heat waves and heat-related mortality.

Global climate change is anticipated to raise overall temperatures and has the potential to increase future mortality attributable to heat. Urban areas are particularly vulnerable to heat because of high concentrations of susceptible people. As the world's largest developing country, China has experienced noticeable changes in climate, partially evidenced by frequent occurrence of extreme heat in urban areas, which could expose millions of residents to summer heat stress that may result in increased health risk, including mortality. While there is a growing literature on future impacts of extreme temperatures on public health, projecting changes in future health outcomes associated with climate warming remains challenging and underexplored, particularly in developing countries. This is an exploratory study aimed at projecting future heat-related mortality risk in major urban areas in China. We focus on the 51 largest Chinese cities that include about one third of the total population in China, and project the potential changes in heat-related mortality based on 19 different global-scale climate models and three Representative Concentration Pathways (RCPs). City-specific risk estimates for high temperature and all-cause mortality were used to estimate annual heat-related mortality over two future twenty-year time periods. We estimated that for the 20-year period in Mid-21st century (2041-2060) relative to 1970-2000, incidence of excess heat-related mortality in the 51 cities to be approximately 37,800 (95% CI: 31,300-43,500), 31,700 (95% CI: 26,200-36,600) and 25,800 (95% CI: 21,300-29,800) deaths per year under RCP8.5, RCP4.5 and RCP2.6, respectively. Slowing climate change through the most stringent emission control scenario RCP2.6, relative to RCP8.5, was estimated to avoid 12,900 (95% CI: 10,800-14,800) deaths per year in the 51 cities in the 2050s, and 35,100 (95% CI: 29,200-40,100) deaths per year in the 2070s. The highest mortality risk is primarily in cities located in the North, East and Central regions of China. Population adaptation to heat is likely to reduce excess heat mortality, but the extent of adaptation is still unclear. Future heat mortality risk attributable to exposure to elevated warm season temperature is likely to be considerable in China's urban centers, with substantial geographic variations. Climate mitigation and heat risk management are needed to reduce such risk and produce substantial public health benefits.

Global climate change is anticipated to raise overall temperatures and is likely to increase future mortality attributable to heat. Urban areas are particularly vulnerable to heat because of high concentrations of susceptible people. As the world’s largest developing country and the largest carbon emitter, China has experienced noticeable changes in climate, partially evidenced by frequent occurrence of extreme heat in urban areas, which could expose millions of residents to summer heat stress that may result in increased health risk, including mortality. While there is a growing literature on future impacts of extreme temperatures on public health, projecting changes in future health outcomes associated with climate warming remains challenging, with the related health impacts in developing countries largely unexplored. This is an exploratory study aimed at projecting future heat-related mortality risk in major metropolitan areas in China. We focus on 50 large Chinese cities that cover about 1/3 of the total population in China, and propose to assess the potential changes in heat-related mortality under 19 different global-scale climate models and three Representative Concentration Pathways (RCPs) used in the latest Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5). We project future changes in heat-related mortality in the 2050s and 2070s relative to the base period of 1950-2000. The projections are based on an integrated assessment framework that combines high-resolution climate model outputs, city-specific temperature-mortality relationships, population projections and baseline mortality rates. Future temperature changes in the study areas are estimated based on downscaled climate model outputs at a spatial resolution of about 1 square kilometer. City-specific historical temperature-mortality associations are obtained from the epidemiological literature. Population projections are based on the China census 2010 survey and projected population growth rates from the 2015 Revision of World Population Prospects by the United Nations. Baseline mortality rates are obtained from China’s national and local health statistics publications. Our findings suggest that future heat mortality risk attributable to elevated warm season temperature is likely to be significant in China’s urban areas, with substantial geographic variations, highlighting the significance of climate mitigation and local-level heat risk management.

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Studies of the adverse impacts of high temperature on human health have primarily focused on urban areas, due in part to urban centers generally having higher population density and often being warmer than surrounding rural areas (the “urban heat island” effect). As a result, urban areas are often considered to be more vulnerable to summer heat. However, heat vulnerability may not only be determined by heat exposure, but also by other population characteristics such as age, education, income, baseline health status, and social isolation. These factors are likely to increase vulnerability among rural populations compared to urban populations. In this exploratory study, we compare the vulnerability to heat-related mortality between rural and urban communities through a systematic review and meta-analysis of existing epidemiological studies, based on the idea that urbanicity can be considered as a “combined” indicator of climate variables and socioeconomic variables. We searched studies that examined the association between high ambient temperature and mortality in both rural and urban settings published between 2000 and 2017. A random-effects meta-analysis of Ratios of Relative Risks (RRR) of heat-related mortality in rural compared to urban areas (RRrural/RRurban) was performed. The pooled RRR was 1.033 (95% CI = 0.969, 1.103), which indicates that the rural relative risk is about 3.3% larger than the urban relative risk. Heterogeneity measures show considerable heterogeneity across studies. Our findings suggest that vulnerability to heat-related mortality in rural areas is likely to be similar to or even greater than urban areas. More studies, particularly studies in developing nations, are needed to understand rural vulnerability to heat hazards as a basis for providing better guidance for heat action plans.

The urban landscape-heat-health relationship was explored using a model of human thermal comfort (as energy budget) modified to incorporate varying urban landscape. Census Tract-level energy budget was modelled in Toronto during four extreme heat events. Energy budgets (~+80 W m-2) and heat-related ambulance calls (~+10%) increased during heat events and were positively correlated, albeit with some event-to-event fluctuation in relationship strength. Heat-related calls were negatively correlated to canopy cover. “Cooling” design strategies applied to two high-energy budget Census Tracts nearly neutralized (~–25 W m-2) thermal comfort and increased canopy cover (500–600%), resulting in an estimated 40–50% reduction in heat-related ambulance calls. These findings advance current understanding of the urban landscape-heat-health relationship and suggest straightforward design strategies to positively influence urban heat-health. This new high-throughput, Census Tract-level thermal comfort modelling methodology incorporates the complexities of the urban landscape has relevance to landscape architecture, urban design, and public health.

abstract: This research is about urban homeless people's vulnerability to extreme temperatures and the related socio-spatial dynamics. Specifically, this research investigates heat related coping strategies homeless people use and how the urban environment setting impacts those coping strategies. Semi-structured interviews were conducted with homeless people in Phoenix, Arizona during the summer of 2010. The findings demonstrate that homeless people have a variety of coping strategies and the urban environment setting unjustly impacts those strategies. The results suggest a need for further studies that focus spatial environmental effects on homeless people and other vulnerable populations. / Dissertation/Thesis / M.S. Justice Studies 2011

abstract: I present the results of studies from two historically separate fields of research: heat related illness and human thermal comfort adaptation. My research objectives were: (a) to analyze the relationships between climate and heat related morbidity in Phoenix, Arizona and Chicago, Illinois; (b) explore possible linkages of human thermal comfort adaptation to heat-related illness; and (c) show possible benefits of collaboration between the two fields of research. Previous climate and mortality studies discovered regional patterns in summertime mortality in North America: lower in hot, southern cities compared to more temperate cities. I examined heat related emergency (911) dispatches from these two geographically and climatically different cities. I analyzed with local weather conditions with 911 dispatches identified by responders as "heat" related from 2001 to 2006 in Phoenix and 2003 through 2006 in Chicago. Both cities experienced a rapid rise in heat-related dispatches with increasing temperature and heat index, but at higher thresholds in Phoenix. Overall, Phoenix had almost two and half times more heat-related dispatches than Chicago. However, Phoenix did not experience the large spikes of heat-related dispatches that occurred in Chicago. These findings suggest a resilience to heat-related illness that may be linked to acclimatization in Phoenix. I also present results from a survey based outdoor human thermal comfort field study in Phoenix to assess levels of local acclimatization. Previous research in outdoor human thermal comfort in hot humid and temperate climates used similar survey-based methodologies and found higher levels of thermal comfort (adaptation to heat) that in warmer climates than in cooler climates. The study presented in this dissertation found outdoor thermal comfort thresholds and heat tolerance levels in Phoenix were higher than previous studies from temperate climates more similar to Chicago. These differences were then compared to the differences in weather conditions associated with heat-related dispatches. The higher comfort thresholds in Phoenix were similar in scale to the climate differences associated with the upsurge in heat-related dispatches in Phoenix and Chicago. This suggests a link between heat related illness and acclimatization, and illustrates potential for collaboration in research between the two fields. / Dissertation/Thesis / Ph.D. Geological Sciences 2012