As individuals and societies become richer, they come into closer contact with one another – virtually, through communication technologies, and physically, through population growth, urbanization, and travel. Meanwhile, rising consumption of products like food, energy, and medicine enhances the externalities, or spillover effects, of individual choices, with the connectivity of global systems increasing these effects’ range and impact.
随着个人和社会的富裕，他们彼此之间的联系也日益紧密——既包括通过通信技术实现的虚拟联系，也包括通过人口增长、城市化和旅行实现的实体联系。与此同时，粮食、能源和药品等产品消费量的增加增强了个体选择的外部性或溢出效应，而全球系统的连通性又增加了这些效应的范围和影响。