In 2023, the Earth experienced unprecedented high temperatures and endured the hottest summer documented since 1880. The extreme temperatures coincided with the publication of Jeff Goodell's The Heat Will Kill You First: Life and Death on a Scorched Planet. The book is essential and accessible reading on the dangers presented by heat for human populations, a guide to the actions needed to reduce these risks, and an inspiration for further research into the implications of global warming.

Goodell is a renowned climate journalist who has written extensively on the topic of climate change, including earlier books on the coal mining industry, climate mitigation, geoengineering, and rising sea levels. In The Heat Will Kill You First, Goodell turns his attention to heat waves, aiming to “convince you to think about heat in a different way” (p. 19). Goodell begins by describing how heat is “invisible” compared with other environmental disasters such as floods, hurricanes, and earthquakes. Those events are sudden and traumatizing and leave a durable mark on the territory and community. While other natural disasters are given names—to support documentation, social memory, and record-keeping—heat waves are unnamed and are sometimes even seen positively, as holiday weather. Despite its relative invisibility compared with other disasters, heat is responsible for the highest yearly death toll attributable to an environmental disaster in some countries. The human thermoregulatory system can fail when exposed to high temperatures for a prolonged time, leading to hyperthermia, heatstroke, and death. Through multiple real-life examples, Goodell shows how heat is a pervasive force that infiltrates homes, exploits vulnerabilities, and proves especially detrimental for those unable to shield themselves.

Goodell pays particular attention to how the impact of heat waves exacerbates social inequalities. For instance, the coexistence of medical conditions such as cardiorespiratory disease or diabetes reduces peoples’ ability to thermoregulate during heat waves. The prevalence of such conditions is a major factor explaining the higher death toll caused by extreme heat in older adults. Goodell shows that age is not the only factor determining increased health risks during a heat wave. For people at younger ages, heat waves remain a major health threat, in particular for those who downplay its risks and do not take precautions, and for those who cannot afford air conditioning or insulation. Socioeconomic status and employment conditions affect the risks posed to individuals by a heat wave. For example, Goodell describes the high exposure of agricultural workers to heat waves and the necessity of adaptation measures to avoid fatalities. Such measures vary in their accessibility or availability creating inequalities in this sector.

Goodell dedicates ample space to the subject of adaptation to heat and the limits of such measures. One informative chapter revolves around the invention and widespread adoption of air conditioning, especially in the United States. Air conditioning provides relief from scorching temperatures to individuals who can afford it, which potentially amplifies inequalities in health and mortality in warmer regions. Furthermore, air conditioning is not a complete solution. During prolonged heat spells and widespread use of air conditioning, electric grid lines are put under high stress and in case of failure could paralyze entire cities.

Other adaptive measures Goodell discusses in the book relate to the challenges faced by cities in an ever more urbanized and hotter world. The formation of urban heat islands puts cities at risk, exacerbating urban–rural inequalities in health. Urban heat islands result from reduced heat release in cities due to factors like limited vegetation, nonreflective surfaces, urban canyon effects, and human activities, making them warmer than rural areas that host more green spaces and water bodies. Some of the solutions discussed in the book relate to urban greening and white rooftop painting but Goodell describes how these innovations face several hurdles. Urban greening could be effective in providing shade and reducing heat islands but challenging in dry and hot regions with limited access to water. Roof painting may not be suitable in historical centers where architectural features of buildings cannot be changed easily.

Migration patterns, too, are heavily influenced by temperature anomalies. Goodell describes a paradoxical phenomenon relating to the increased internal migration in the United States of individuals into areas classified as having a higher climatic risk. In particular, several areas in the South that are badly affected by heat waves and sea level rise experience larger population growth as people retire to warmer climes. The combination of rising population and escalating climatic risks may pose significant challenges for these areas in the future. Conversely, for the economically disadvantaged who increasingly suffer the consequences of climate change, migration is often the ultimate solution to escape inhospitable climatic conditions that render certain economic activities such as agriculture unfeasible. At the same time, migratory paths are becoming increasingly perilous and impractical due to worsening weather conditions.

Goodell's book covers three principal themes relating to heat and humanity that have been of particular concern for population scholars: the increasing prevalence of heat waves and their broad impacts on population outcomes; the importance and complexity of adaptation measures; and the amplification of existing sociodemographic inequalities due to climate-induced challenges. In recent years, academic research on the implications of heat waves has intensified. A recent study marked the catastrophic European heat wave of 2003, responsible for approximately 70,000 deaths, as a significant inflection point leading to an increase in studies on temperature-related mortality and morbidity (Campbell et al., 2018). In 2022, heat waves determined about 60,000 deaths in Europe indicating that the impact of heat waves remains deadly, raising concerns about the ability of individuals to adapt to rising temperatures (Ballester et al., 2023). The increasing prevalence of heat waves makes studies on the population implications of climate change particularly pressing.

Goodell provides novel perspectives to population scholars, delving into relatively unexplored topics in existing demographic research. He highlights how climate change can create environments that favor the spread of disease vectors, such as mosquitoes and ticks. This may result in a wider distribution of diseases like dengue, Lyme disease, and malaria, determining new challenges to public health and human mortality. Additionally, an important area of research highlighted in the book is climate change attribution which seeks to understand whether specific environmental disasters arise from natural climatic variations or are determined by human activities and greenhouse gas emissions. More research is needed on this topic, to complement existing studies calculating the mortality cost of carbon (number of deaths caused by CO₂ emissions) (Bressler, 2021) and estimating the burden of heat-related mortality determined by human-led climate change (Vicedo-Cabrera et al., 2021). Further studies on the demographic and health cost of anthropogenic climate change are essential as well as on the potential of mitigation to limit such impacts.

While Goodell's book discusses the effects of heat on migration, mortality, and morbidity, it does not delve so deeply into its impact on fertility, perinatal, and maternal health. Compared with mortality, research on the impact of heat on such outcomes has been more limited. Despite some recent interest in the impact of heat on fertility and birth outcomes, there remain many unresolved questions on this topic (Barreca et al., 2018; Chersich et al., 2020; Hajdu & Hajdu, 2022). The mechanisms linking temperature with fertility are still debated and are critical to comprehending how heat shapes reproductive health and behavior in a world with low fertility rates and an aging population. The book could also have delved deeper into the compounding impact on public health and demographic dynamics when multiple environmental disasters simultaneously impact a population. Such compound effects are especially pronounced in regions where heat waves occur simultaneously with wildfires or flooding events, potentially amplifying the impact on public health outcomes.

This public science book reads effortlessly and is written in a journalistic style, combining scientific evidence with the lived experiences of individuals suffering the negative consequences of heat. Each chapter reads as a standalone story that covers in depth how heat affects a particular aspect of life, ranging from agricultural work and the spread of vector-borne diseases to survival in boiling cities and the invention of air conditioning, making the text an easy reference volume. Consequently, it offers an insightful read both for the general public and the expert reader, underlining the pressing challenges determined by heat for human life on Earth. As reflected in the book's provoking title, the pervasive effects of heat will inevitably touch us all, compelling us to grapple with its implications.

2023 年，地球经历了前所未有的高温，并经历了自 1880 年以来有记录以来最热的夏季。极端气温恰逢杰夫·古德尔的《热气将首先杀死你：烧焦的星球上的生与死》出版。这本书是关于高温给人类带来的危险的重要读物，是减少这些风险所需行动的指南，并为进一步研究全球变暖的影响提供了灵感。

古德尔是一位著名的气候记者，他撰写了大量有关气候变化主题的文章，包括早期有关煤炭开采业、气候缓解、地球工程和海平面上升的书籍。在《热浪会先杀死你》一书中，古德尔将注意力转向热浪，旨在“说服你以不同的方式思考热”（第 19 页）。古德尔首先描述了与洪水、飓风和地震等其他环境灾难相比，热量是如何“看不见的”。这些事件是突然的、令人痛苦的，并在该地区和社区留下了持久的印记。虽然其他自然灾害都有名称，以支持记录、社会记忆和记录保存，但热浪却没有命名，有时甚至被积极地视为假日天气。尽管与其他灾害相比，高温相对不易察觉，但在一些国家，高温却是每年因环境灾难造成的死亡人数最高的原因。当长时间暴露在高温下时，人体的体温调节系统可能会出现故障，导致体温过高、中暑和死亡。通过多个现实生活中的例子，古德尔展示了热量是如何渗透到家庭、利用脆弱性的普遍力量，并且对那些无法保护自己的人尤其有害。

古德尔特别关注热浪的影响如何加剧社会不平等。例如，心肺疾病或糖尿病等疾病的共存会降低人们在热浪期间的体温调节能力。这种情况的普遍存在是导致老年人因酷热而死亡人数增加的一个主要因素。古德尔表明，年龄并不是决定热浪期间健康风险增加的唯一因素。对于年轻人来说，热浪仍然是一个主要的健康威胁，特别是对于那些淡化其风险且不采取预防措施的人，以及那些买不起空调或隔热材料的人来说。社会经济地位和就业条件会影响热浪对个人造成的风险。例如，古德尔描述了农业工人高度暴露于热浪以及采取适应措施以避免死亡的必要性。这些措施的可及性或可用性各不相同，造成了该部门的不平等。

古德尔用了充足的篇幅讨论了适应高温的主题以及此类措施的局限性。其中一章内容丰富，围绕空调的发明和广泛采用，尤其是在美国。空调可以为有能力的人缓解炎热的天气，这可能会加剧温暖地区健康和死亡率的不平等。此外，空调并不是一个完整的解决方案。在长时间的炎热天气和空调的广泛使用期间，电网线路承受着很高的压力，如果出现故障，可能会导致整个城市瘫痪。

古德尔在书中讨论的其他适应性措施涉及城市在日益城市化和炎热的世界中所面临的挑战。城市热岛的形成使城市面临风险，加剧城乡健康不平等。城市热岛是由于植被有限、表面不反射、城市峡谷效应和人类活动等因素导致城市热量释放减少造成的，使城市比拥有更多绿地和水体的农村地区更温暖。书中讨论的一些解决方案涉及城市绿化和白色屋顶绘画，但古德尔描述了这些创新如何面临一些障碍。城市绿化可以有效地提供遮荫和减少热岛效应，但在水资源有限的干燥和炎热地区却具有挑战性。屋顶粉刷可能不适合历史中心，因为建筑物的建筑特征不易改变。

迁移模式也受到温度异常的严重影响。古德尔描述了一种自相矛盾的现象，该现象与美国境内越来越多的人迁移到气候风险较高的地区有关。特别是南方一些受热浪和海平面上升严重影响的地区，随着人们退休到气候温暖的地区，人口增长幅度更大。人口增长和气候风险升级相结合可能会给这些地区未来带来重大挑战。相反，对于日益遭受气候变化后果的经济弱势群体来说，移民往往是逃避恶劣气候条件的最终解决方案，因为恶劣的气候条件使农业等某些经济活动变得不可行。与此同时，由于天气条件恶化，迁徙路径变得越来越危险和不切实际。

古德尔的书涵盖了人口学者特别关注的与高温和人类相关的三个主要主题：热浪的日益流行及其对人口结果的广泛影响；适应措施的重要性和复杂性；以及由于气候引发的挑战而加剧现有的社会人口不平等。近年来，关于热浪影响的学术研究不断加强。最近的一项研究将 2003 年造成约 70,000 人死亡的灾难性欧洲热浪视为一个重要的拐点，导致与温度相关的死亡率和发病率的研究增加（Campbell 等，2018 ）。2022 年，热浪导致欧洲约 60,000 人死亡，这表明热浪的影响仍然是致命的，引发人们对个人适应气温上升的能力的担忧（Ballester 等，2023）。热浪的日益普遍使得气候变化对人口影响的研究变得尤为紧迫。

古德尔为人口学者提供了新颖的视角，深入研究了现有人口研究中相对未探索的主题。他强调了气候变化如何创造有利于蚊子和蜱虫等疾病媒介传播的环境。这可能导致登革热、莱姆病和疟疾等疾病的更广泛传播，给公共卫生和人类死亡率带来新的挑战。此外，书中强调的一个重要研究领域是气候变化归因，旨在了解特定的环境灾害是由自然气候变化引起还是由人类活动和温室气体排放决定。_{需要对此主题进行更多研究，以补充计算碳死亡率成本（CO 2}排放造成的死亡人数）的现有研究（Bressler， 2021）并估计由人类主导的气候变化决定的与高温相关的死亡率负担（ Vicedo-Cabrera 等人，2021）。对人为气候变化造成的人口和健康成本以及缓解措施限制此类影响的潜力进行进一步研究至关重要。

虽然古德尔的书讨论了高温对移民、死亡率和发病率的影响，但它并没有深入探讨其对生育力、围产期和孕产妇健康的影响。与死亡率相比，关于高温对此类结果影响的研究更为有限。尽管最近人们对高温对生育和出生结果的影响产生了一些兴趣，但该主题仍然存在许多未解决的问题（Barreca et al., 2018 ; Chersich et al., 2020 ; Hajdu & Hajdu, 2022）。将温度与生育力联系起来的机制仍然存在争议，并且对于理解在低生育率和人口老龄化的世界中热量如何影响生殖健康和行为至关重要。该书还可以更深入地探讨当多种环境灾难同时影响人口时对公共卫生和人口动态的复合影响。这种复合效应在热浪与野火或洪水事件同时发生的地区尤其明显，可能会放大对公共卫生结果的影响。

这本公共科学书籍读起来毫不费力，以新闻风格编写，将科学证据与遭受高温负面后果的个人的生活经历结合起来。每一章都作为一个独立的故事来阅读，深入介绍了热量如何影响生活的特定方面，从农业工作和病媒传播疾病的传播到沸腾的城市中的生存和空调的发明，使文本成为一个简单的参考体积。因此，它为普通公众和专家读者提供了一篇富有洞察力的读物，强调了地球上人类生命面临的紧迫挑战。正如这本书的标题所反映的那样，炎热的普遍影响将不可避免地触及我们所有人，迫使我们努力应对其影响。