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Climate change looms as the biggest threat of the 21st century, and its effect on urban mortality is exacerbated by urban heat islands. This study analyzes the impact of high temperatures, heatwaves, and the urban heat island on the cardiovascular and respiratory mortality of people over 65 years of age for the years 2002 to 2012. The area of application is Athens, Greece, an urban agglomeration experiencing an urban heat island of high intensity. The correlation of the daily cardiovascular and respiratory mortality count of people over 65 years of age with various temperature measures confirmed a U-shaped exposure response curve, with fewer deaths in the range of moderate temperatures. At high and very high temperatures, this mortality increased by 20% to 35% correspondingly, at a 99.9% significance level. Mortality was further investigated with ordinary least squares, Poisson, and negative binomial times series models, which, although suffering from poor fit, showed a one-day lag for the maximum temperature effect on mortality. Finally, cluster analysis for observations confined to May to September, confirmed by multiple discriminant analysis, showed the existence of six clusters, with the highest excess mortality count of 23% for the cluster that included the hottest days and 20.6% for the heatwave cluster. To this end, it is recommended that policies target high ambient temperatures and heatwaves as a priority.

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This chapter examines the role of renewable energy in shaping energy security against the backdrop of global geopolitical, socioeconomic, and technological uncertainties. The evolving definition of energy security during the twentieth and early twenty-first centuries is discussed initially. The dimensions, components, and metrics of energy security are reviewed, including the 4A definition of energy security that comprises physical availability; economic affordability; accessibility from a sociopolitical standpoint; and environmental acceptability. A novel energy security index is proposed, with the following components: physical availability; technology development; economic affordability; social accessibility; governance; unconventional threats; and natural environment. Of these, physical availability followed by technology development, economic affordability, and governance was rated as the most important, and the environment was rated as the least important by a small panel of experts. The roles of wind and solar energy are highlighted, with an emphasis on the social acceptance of renewable energy in an energy security context. Other energy security indexes are discussed, focusing on sustainability and renewable energy. Denmark, Germany, China, Russia, and the United States are examined as case studies that help understand the transition to renewable energy in the context of coopetition among states. As these countries face different political concerns, geopolitical realities, and energy security issues, they consider different policy approaches to address them.

Urbanization and climate change are two major issues that humanity faces in the 21st century. Megacities are large urban agglomerations with more than 10 million inhabitants that emerged in the 20th century. The world’s top 100 economies include many North and South American megacities, such as New York, Los Angeles, Mexico City, Sao Paulo and Buenos Aires; European cities such as London and Paris; and Asian cities such as Tokyo, Osaka, Seoul, Beijing and Mumbai. This paper addresses a dearth of megacity energy metabolism models in the literature. Cross-sectional data for 36 global megacities were collected from many literature and Internet sources. Variables included megacity name, country and region; population; area; population density; (per capita) GDP; income inequality measures; (per capita) energy consumption; household electricity prices; (per capita) carbon and ecological footprint; degree days; average urban heat island intensity; and temperature and precipitation. A descriptive comparison of the characteristics of megacities was followed by ordinary least squares with heteroskedasticity-robust standard errors that were used to estimate four alternative multiple regression models. The per-capita carbon footprint of megacities was positively associated with the megacity GDP per capita, and the megacity ecological footprint; and negatively associated with country income inequality, a low-income country dummy, the country household electricity price, and the megacity annual precipitation. Targeted policies are needed, but more policy autonomy should be left to megacities. Collecting longitudinal data for megacities is very challenging but should be a next step to overcome misspecification and bias issues that plague cross-sectional approaches.