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(a) Magnitude and duration of power outages in the US from 2000 to 2015. Incidents lasting less than 10 h or affecting less than 100 000 customers are excluded. A notable example is the June 2012 Midwest storm event (derecho) that coincided with a heatwave. Reportedly, 20 people died due to exposure to heat inside buildings that lost AC due to the power outage. However, evidence from previous events suggests that this number is a significant underestimation of actual death toll due to AC loss (Fowler et al 2013). (b) Annual trend of total exposure to power outages (customers affected × power outage duration). Raw data from the US Department of Energy.
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Heat is the number one weather-related killer in the United States and indoor exposure is responsible for a significant portion of the resulting fatalities. Evolving construction practices combined with urban development in harsh climates has led building occupants in many cities to rely on air conditioning (AC) to a degree that their health and we...
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The spatio-temporal variability of temperatures in cities impacts human well-being, particularly in a large metropolis. Low-cost sensors now allow the observation of urban temperatures at a much finer resolution, and, in recent years, there has been a proliferation of fixed and mobile monitoring networks. However, how to design such networks to max...
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... Furthermore, recent studies, including those by Sailor et al. [42] and Tamerius et al. [44] have extensively documented the influence of outdoor variability on indoor thermal conditions. However, the literature still lacks enough research concentrating on other environmental factors, such as relative humidity, metabolic rate, air speed, and clothing insulation, which could contribute to indoor thermal stress and affect occupants. ...
In the face of escalating global climate change and the increasing frequency of extreme heat events, the mitigation of building overheating has become an urgent priority. This comprehensive review converges insights from building science and public health domains to offer a thorough understanding of the multifaceted impacts of indoor overheating on occupants. The paper addresses a significant research gap by offering a holistic exploration of indoor overheating of residential buildings and its consequences, with a specific focus on the United States, an economically diverse nation that has been underrepresented in the literature. The review illuminates the effects of overheating on thermal comfort, health, and socio-economic aspects within the built environment. It emphasizes associated repercussions, including heightened cooling energy consumption, increased peak electricity demand, and elevated vulnerability, leading to exacerbated heat-related mortality and morbidity rates, especially among disadvantaged groups. The study concludes that vulnerabilities to these impacts are intricately tied to regional climatic conditions, highlighting the inadequacy of a one-size-fits-all approach. Tailored interventions for each climate zone are deemed necessary, considering the consistent occurrence of indoor temperatures surpassing outdoor levels, known as superheating, which poses distinct challenges. The research underscores the urgency of addressing indoor overheating as a critical facet of public health, acknowledging direct socioeconomic repercussions. It advocates for further research to inform comprehensive policies that safeguard public health across diverse indoor environments.
... In the United States, cities are typically 1-4°C hotter compared to surrounding rural areas (US EPA, 2022). As a result, human health (Ebi et al., 2018;Habeeb et al., 2015) and urban infrastructure (Clark et al., 2018;Sailor et al., 2019) are negatively impacted. Growing evidence suggests that heat exposure also disproportionally affects low-income communities and people of color (Klinenberg, 2003;Wilson, 2020). ...
... While heat exposure deaths in the USA are relatively rare (Lowe, 2016), they're the leading weather-related cause of death (Lee, 2014;Sheridan & Allen, 2018) and are associated with many negative health outcomes (Harlan et al., 2007). The repercussions extend beyond direct fatalities to increased hospitalization (Basu, 2009), respiratory illness (D'Ippoliti et al., 2010), heat-related mortality risks (Hajat et al., 2014), heightened energy costs (Sailor et al., 2019;Thomson et al., 2019), and diminished productivity (Lundgren et al., 2013) -all exacerbating societal inequalities, physical discomfort (Guardaro et al., 2020) and mental stress (Hansen et al., 2008). ...
... Due to this combination of climate change and urban-induced warming, what we currently deem as "extreme" heat could become the norm by mid-century (4). Further, climate change-related threats such as wildfires increase the risk of infrastructure failures, which, coinciding with hot weather, can result in drastic outcomes (eg, a city-wide blackout during hot weather) (5). In light of these alarming trends, this editorial summarizes the challenges facing the older adult population and proposes areas of research aimed at helping them adapt to the new climate reality. ...
... In addition, the substantial increases in the intensity and frequency of summer peak electricity demand in U.S. urban areas (e.g., Supplementary Fig. 10) could necessitate not only a higher grid capacity but also greater resilience against blackouts during extreme heat waves. Recent studies have highlighted the rapidly elevated risks of heat-related mortality and morbidity during compound heat wave and grid failure events in several U.S. urban areas 30,31 . Given the anticipated rise in urban cooling demand across all warming scenarios ( Supplementary Fig. 1), enhancing power grid resilience will become increasingly crucial to mitigate potential health risks and cope with heat extremes. ...
Climate, technologies, and socio-economic changes will influence future building energy use in cities. However, current low-resolution regional and state-level analyses are insufficient to reliably assist city-level decision-making. Here we estimate mid-century hourly building energy consumption in 277 U.S. urban areas using a bottom-up approach. The projected future climate change results in heterogeneous changes in energy use intensity (EUI) among urban areas, particularly under higher warming scenarios, with on average 10.1–37.7% increases in the frequency of peak building electricity EUI but over 110% increases in some cities. For each 1 °C of warming, the mean city-scale space-conditioning EUI experiences an average increase/decrease of ~14%/ ~ 10% for space cooling/heating. Heterogeneous city-scale building source energy use changes are primarily driven by population and power sector changes, on average ranging from –9% to 40% with consistent south–north gradients under different scenarios. Across the scenarios considered here, the changes in city-scale building source energy use, when averaged over all urban areas, are as follows: –2.5% to –2.0% due to climate change, 7.3% to 52.2% due to population growth, and –17.1% to –8.9% due to power sector decarbonization. Our findings underscore the necessity of considering intercity heterogeneity when developing sustainable and resilient urban energy systems.
... Third, although we use ambient (outdoor) 2-m air temperature to estimate geographic population heat hazard as it relates to temperatures above these thresholds, people often stay indoors on hot days and may not sit in the shade outside using a fan. Future work could model indoor temperatures based on building characteristics and outdoor ambient climate conditions (e.g., Sailor et al., 2019). Fourth, we have focused on temperature thresholds recommended in the Lancet . ...
As the globe warms, people will increasingly need affordable, safe methods to stay cool and minimize the worst health impacts of heat exposure. One of the cheapest cooling methods is electric fans. Recent research has recommended ambient air temperature thresholds for safe fan use in adults. Here we use hourly weather reanalysis data (1950–2021) to examine the temporal and spatial evolution of ambient climate conditions in the continental United States (CONUS) considered safe for fan use, focusing on high social vulnerability index (SVI) regions. We find that although most hours in the day are safe for fan use, there are regions that experience hundreds to thousands of hours per year that are too hot for safe fan use. Over the last several decades, the number of hours considered unsafe for fan use has increased across most of the CONUS (on average by ∼70%), with hotspots across the US West and South, suggesting that many individuals will increasingly need alternative cooling strategies. People living in high‐SVI locations are 1.5–2 times more likely to experience hotter climate conditions than the overall US population. High‐SVI locations also experience higher rates of warming that are approaching and exceeding important safety thresholds that relate to climate adaptation. These results highlight the need to direct additional resources to these communities for heat adaptive strategies.
... To accomplish effective cross-ventilation, they recommended two primary measures: first, the addition of decorative metalwork on classroom windows to provide security for overnight ventilation when outside air is coolest, and second, the addition of transom windows to classroom doors and walls to provide airflow paths across the corridor. Participants did not favor the addition of air-conditioning, however, because of its cost, ongoing maintenance needs, and vulnerability to power outages (Sailor et al. 2019). They noted, however, that shading and natural ventilation would greatly reduce cooling loads even if air-conditioning were added in the future. ...
... Further, the reliability of a city's infrastructure and utilities during extreme weather may also play a role. For example, if part of a metropolitan area experiences electrical grid failures during a heat wave, this could increase the vulnerability of that specific population (Sailor et al., 2019;Stone et al., 2021). Taken together, the above factors may explain why people living in areas with UHIs likely experience greater heat-related CVD impacts. ...
Many United States (US) cities are experiencing urban heat islands (UHIs) and climate change-driven temperature increases. Extreme heat increases cardiovascular disease (CVD) risk, yet little is known about how this association varies with UHI intensity (UHII) within and between cities. We aimed to identify the urban populations most at-risk of and burdened by heat-related CVD morbidity in UHI-affected areas compared to unaffected areas. ZIP code-level daily counts of CVD hospitalizations among Medicare enrollees, aged 65-114, were obtained for 120 US metropolitan statistical areas (MSAs) between 2000 and 2017. Mean ambient temperature exposure was estimated by interpolating daily weather station observations. ZIP codes were classified as low and high UHII using the first and fourth quartiles of an existing surface UHII metric, weighted to each have 25% of all CVD hospitalizations. MSA-specific associations between ambient temperature and CVD hospitalization were estimated using quasi-Poisson regression with distributed lag non-linear models and pooled via multivariate meta-analyses. Across the US, extreme heat (MSA-specific 99th percentile, on average 28.6 °C) increased the risk of CVD hospitalization by 1.5% (95% CI: 0.4%, 2.6%), with considerable variation among MSAs. Extreme heat-related CVD hospitalization risk in high UHII areas (2.4% [95% CI: 0.4%, 4.3%]) exceeded that in low UHII areas (1.0% [95% CI: -0.8%, 2.8%]), with upwards of a 10% difference in some MSAs. During the 18-year study period, there were an estimated 37,028 (95% CI: 35,741, 37,988) heat-attributable CVD admissions. High UHII areas accounted for 35% of the total heat-related CVD burden, while low UHII areas accounted for 4%. High UHII disproportionately impacted already heat-vulnerable populations; females, individuals aged 75-114, and those with chronic conditions living in high UHII areas experienced the largest heat-related CVD impacts. Overall, extreme heat increased cardiovascular morbidity risk and burden in older urban populations, with UHIs exacerbating these impacts among those with existing vulnerabilities.
... Para a identificação da insalubridade térmica de um ambiente, seja ele interno ou externo, índices de conforto térmico historicamente têm sido empregados (FANGER, 1973;FANGER et al., 1974;HUMPHREYS, 1976;DE DEAR, 2004;van HOOF, 2008;DJONGYANG et al., 2010;ENESCU, 2017;DZYUBAN et al., 2022). Entretanto, acredita-se ainda que a combinação entre o uso de índices de conforto e uma análise histórica e geográfica da exposição diferencial dos grupos sociais pode contribuir de modo mais eficiente para um entendimento mais detalhado e assertivo acerca do calor urbano como determinante ambiental (INDRAGANTI; RAO, 2010;SAILOR et al., 2019). ...
A partir de fins do século XIX, o Rio de Janeiro assistiu a burguesia emergente se locomover em direção à Zona Sul da cidade como consequência das crescentes práticas de incorporação de terrenos para comercialização. Ao mesmo tempo, o eixo de forte crescimento populacional da também nascente classe trabalhadora se direcionava para as zonas Norte e Oeste da cidade. No decorrer dos séculos XX e XXI, essa dinâmica seguiu, então orientada pelos processos de industrialização e explosão das atividades comerciais associadas às políticas públicas de “revitalização” da área central do Rio de Janeiro. Esse conjunto de processos acabou por fortalecer a ocupação de áreas suburbanas que, em grande medida, até os dias atuais encontram-se desigualmente servidas de acesso aos sistemas básicos infraestrutura. Neste contexto, esta dissertação tem como objetivo analisar as áreas de potencial desconforto térmico pelo calor em ambientes externos no subúrbio da cidade do Rio de Janeiro, mais especificamente no subúrbio de Irajá. A partir da abordagem teórica da Geografia do Clima, utilizou-se a proposta metodológica dos UC - Maps (Urban Climate Maps) para identificar tais áreas. Técnicas de geoprocessamento e sensoriamento remoto foram combinadas à aspectos de uso e de cobertura da terra na geração de um mapa-síntese que associou a capacidade térmica da área com o seu potencial dinâmico. Posteriormente, foram identificados e analisados o campo térmico e higrométrico do subúrbio de Irajá de acordo com os dados registrados por meio de sensores Hobo previamente calibrados. A análise foi realizada para toda a série histórica (2021/2022), bem como foram realizadas análises sazonais, mensais e horárias - esta última com vistas a caracterizar as condições de temperatura e umidade relativa do ar em horários críticos de circulação de pedestres. Por fim, essas informações foram relacionadas às classes existentes ao índice de conforto térmico - Índice de Temperatura Efetiva (TEf), com vistas a identificar as áreas potenciais de desconforto ao calor. Foi observado que nas análises sazonais e anuais, não houveram mudanças quanto aos pontos mais aquecidos (Ponto P2) e mais amenos (P1 e P3). Contudo, na análise horária, a influência da radicação solar associada ao uso e cobertura da terra e as dinâmicas socioespaciais fomentaram uma flutuabilidade dos pontos mais aquecidos e mais amenos durante o dia.
... Exposure to an extreme thermal environment can lead to the failure of this thermoregulatory mechanism. In a hot environment, for instance, the human body may produce or absorb more heat than it dissipates, thus increasing its core temperature to values that can potentially cause discomfort, heat-related illnesses, and ultimately death (Kovats & Hajat, 2008;Sailor et al., 2019). Furthermore, mild weather, which describes a condition that is neither too cold nor too hot (i.e., comfortable), is also of great societal significance; for example, human outdoor activities such as tourism, sports, building construction, and transport can benefit from mild weather (Lin et al., 2019;van der Wiel et al., 2017). ...
Changes in the thermal comfort condition of the living environment of human beings are one of the main concerns related to global warming. While previous studies largely focused on mean temperature and warm/cold extremes, changes in thermal comfort conditions (both comfort and discomfort conditions) have not been adequately revealed. Based on climate projections from the Coupled Model Intercomparison Project phase 6 (CMIP6), future thermal comfort conditions over global land using net effective temperature index that considers the aggregate effects of temperature, relative humidity, and wind on human thermal perception were investigated. The focus was on the projected changes in thermal comfort conditions in different regions based on GDP per capita, an indicator of adaptive capacity. An inequitable impact of escalating global warming on thermal comfort conditions emerges: in high-income regions (mostly distributed in cool mid-high latitudes), a diminishing number of cold-uncomfortable days and an increasing number of comfort days collectively would contribute to an improvement in thermal comfort conditions; however, in low-income regions (mostly distributed in warmer low latitudes), thermal comfort conditions are expected to worsen as a result of a dramatic increase in the number of warm-uncomfortable days that greatly exceeds the decrease in the number of cold-uncomfortable days and a decrease in the number of comfortable days. Moreover, analysis accounting for population exposure suggests that the overall impact of future changes in thermal comfort conditions on the global population is negative. Therefore, prioritized support for climate mitigation and adaptation to developing nations is justified and urgently needed.
... However, normal HVAC system operation is dependent on a stable power supply. As demonstrated in prior events and in the literature, power grid operation can be vulnerable to unexpected failures during extreme heat and freezing events [2][3][4]. The adoption and usage of HVAC systems are also impacted by other cultural and socio-economic factors. ...
