根据联合国目前的人口估计，未来几十年世界人口预计将超过90亿。<br> <br>几乎所有的增长都将来自新兴经济体，而现代基础设施导致各种各样的健康问题-难以获得水或水质差，空气污染，废物或垃圾收集或处理系统不足。<br> <br>城市为容纳不断增长的人口提供了机会–降低人均能源消耗，集中工作和社会资源，提供支持我们文明的各种服务的效率。城市也存在自身的问题，约占地球所有能源使用和碳排放量的四分之三，给环境造成了沉重负担。<br> <br>然而，世界的三分之二到2050年，人口将集中在人口稠密的城市地区，另
The world's population is growing. And with an increase in population comes a need for civil and environmental engineers to create solutions that accommodate this growth sustainably. Emerging economies will account for much of the future population growth without the adequate resources to handle it. The lack of modern infrastructure will lead to a variety of health concerns poor access to water or poor water quality, air pollution, inadequate systems for the collection or treatment of wastes and trash.<br><br>Much of the world's population is concentrated in dense, urban areas. Cities offer opportunities for accommodating this growing population with lower per-capita energy consumption, concentrated jobs and social resources, and efficiency in delivering all manner of services that support our civilization.