策划人语:在《能量、环境与经济》中,美国著名生态学家H.T欧登描述了对未来的设想:“未来人类社会和生活的变化,将包括由人口密集的城市化模式向分散的农村模式发展:……。未来是从城市向乡村发展和转化。”乍然而观,欧登的描述有些匪夷所思。但是,将视线从发展中国家转向发达国家,却也所言非虚。1990年,有近半数美国人口居住在百万人口以上的大型都市。同时,人口规模 Planning language: In “Energy, Environment and Economy,” HT Oden, a famous American ecologist, described his vision for the future: “Future changes in human society and life will include a shift from a densely populated urbanization pattern to decentralization The development of the rural model: ...... The future is from the city to the rural development and transformation. ”At first glance, the description of Oden some incredible. However, turning their attention away from developing countries to the developed countries has also said nothing. In 1990, nearly half of the U.S. population lived in mega-cities with more than one million people. At the same time, the population size