No abstract

Evidence for nation-states suggests that the long-standing negative relationship between fertility and economic development might turn positive at high levels of development. The robustness of the reversal continues to be debated. We add to this discussion from a novel angle by considering whether such a reversal could also occur at the sub-national level within highly developed countries. Our contributions are both theoretical and empirical. We first discuss important trends which might foster the emergence of a positive fertility–development relationship across regions of highly developed countries. These include shifts in family policies, changes in the spatial organisation of the economic sphere, and selective international and internal migration processes. In order to explore whether we observe tendencies towards a reversal, we investigate data covering 20 European countries subdivided in 256 regions between 1990 and 2012. We document a weakening of the negative relationship between fertility and economic development within many countries, and among some countries the emergence of a positive relationship. These findings do not seem to be driven by postponement effects alone. However, there is substantial variation in the fertility and the economic development levels at which such tendencies towards a reversal are observed. Electronic supplementary material The online version of this article (10.1007/s10680-018-9485-1) contains supplementary material, which is available to authorized users.

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Overheated outdoor environments adversely impact urban sustainability and livability. Urban areas are particularly affected by heat waves and global climate change, which is a serious threat due to increasing heat stress and thermal risk for residents. The tropical city of Darwin, Australia, for example, is especially susceptible to urban overheating that can kill inhabitants. Here, using a modeling platform supported by detailed measurements of meteorological data, we report the first quantified analysis of the urban microclimate and evaluate the impacts of heat mitigation technologies to decrease the ambient temperature in the city of Darwin. We present a holistic study that quantifies the benefits of city-scale heat mitigation to human health, energy consumption, and peak electricity demand. The best-performing mitigation scenario, which combines cool materials, shading, and greenery, reduces the peak ambient temperature by 2.7 °C and consequently decreases the peak electricity demand and the total annual cooling load by 2% and 7.2%, respectively. Further, the proposed heat mitigation approach can save 9.66 excess deaths per year per 100,000 people within the Darwin urban health district. Our results confirm the technological possibilities for urban heat mitigation, which serves as a strategy for mitigating the severity of cumulative threats to urban sustainability. Urban areas face several challenges, including increased energy and resources consumption, health risks and vulnerability to extreme events 1 , that must be counteracted by structures and processes that advance the well-being of people and the planet to ensure the sustainability of urban systems 2. Additional man-made changes to local and regional climate 3 and the localized effects of urbanization induce higher surface and air temperatures in cities compared to those in rural areas 4 , a phenomenon known as the urban heat island (UHI) effect. The magnitude of a UHI varies between 0.4 °C and 11 °C 5 and is affected by synoptic weather conditions, the local morphology and structure of the city, urban materials, anthropogenic heat generation by human activities, and heat sinks 6. This effect is further exacerbated by global climate change leading to more frequent heat waves 7,8 and severe consequences for urban sustainability. UHI is documented in more than 400 major cities around the world 5,9. UHIs increase the cooling energy demand of buildings depending on the magnitude of the urban overheating, microclimate, building characteristics and performance of air conditioning systems. On average, UHIs increase the cooling loads of urban buildings by 13.1% compared to rural buildings reference demand 10. Each degree of temperature rise results in a 0.45-4.6% increase in the peak electricity demand, which leads to an electricity penalty of 21 (± 10.4) W/°C/person 11. On top of the effects of urbanization, climate change and market penetration of air conditioning will put further stress on urban energy systems. It is expected that the average cooling energ...