Energy Systems and Population Health
It is well-documented that energy and energy systems have a central role in social and economic development and human welfare at all scales, from household and community to regional and national (41). Among its various welfare effects, energy is closely linked with people s health. Some of the effects of energy on health and welfare are direct. With abundant energy, more food or more frequent meals can be prepared; food can be refrigerated, increasing the types of food items that are consumed and reducing food contamination; water pumps can provide more water and eliminate the need for water storage leading to contamination or increased exposure to disease vectors such as mosquitoes or snails; water can be disinfected by boiling or using other technologies such as radiation. Other effects of energy on public health are mediated through more proximal determinants of health and disease. Abundant energy can lead to increased irrigation, agricultural productivity, and access to food and nutrition; access to energy can also increase small-scale income generation such as processing of agricultural commodities (e.g., producing refined oil from oil seeds, roasting coffee, drying and preserving fruits and meats) and production of crafts; ability to control lighting and heating allows education or economic activities to be shielded from daily or seasonal environmental constraints such as light, temperature, rainfall, or wind; time and other economic resources spent on collecting and/or transporting fuels can be used for other household needs if access to energy is facilitated; energy availability for transportation increases access to health and education facilities and allow increased economic activity by facilitating the transportation of goods and services to and from markets; energy for telecommunication technology (radio, television, telephone, or internet) provides increased access to information useful for health, education, or economic purposes; provision of energy to rural and urban health facilities allows increased delivery and coverage of 3 various health services and interventions such as tests and treatments, better storage of medicine and vaccines, disinfection of medical equipment by boiling or radiation, and more frequent and efficient health system encounters through mobile clinics or longer working hours; and so on. In fact, while the dominant view of development-energy-health linkages has been that improvements in energy and health are outcomes of the socioeconomic development process (e.g., the "energy ladder" framework discussed below), it has even been argued that access to higher quality energy sources and technologies can initiate a chain of demographic, health, and development outcomes by changing the household structure and socioeconomic relationships. For example, in addition to increased opportunities for food and income production, reduced infant mortality as a result of transition to cleaner fuels or increased coverage of vaccination with availability of refrigerators in rural clinics may initiate a process of "demographic transition" to low-mortality and low-fertility populations (14). Such a transition has historically been followed with further improvements in maternal and child health and increased female participation in the labor markets and other economic activities.