Scientific Name For Dog

millions

Cities

world

The 63 cities and more than five million people joined together 637 million, which means that about 10% of the world's population lives in one of these megacities, or what is the same , they are concentrated in one in ten people on the planet. It highlights 35 cities of more than eight million people in total more than 500 million home. Of these, there are 25 large cities of ten million inhabitants and over: Real megacities! What has happened? From eco-demographic three major processes: high natural growth of human population on the road to the "demographic transition", which means maintaining high birth rates in an urban context that helps to reduce mortality rates flow of rural migrants and urban small towns, seeking opportunities for social, economic, cultural and political concentrated the main town in the early stages of the development (construction workers, technicians, etc.): and a new classification of rural to urban settlements by simply changing the size or the addition of peripheral populations due to the physical expansion urban area (metropolitan area).

The role of these cities, to say Fuchs, has two faces: one side

megacities are the engines of economic growth and regional and national centers of technological and cultural creativity.

At the same time, are home to the poor and destitute, and place and source of pollution. In general, these cities, at least in developing countries and poor, lack the industrial base should rest on its expansion and growth, there also is planned or not an administrative organization to ensure the appropriate action urban public services, and social, to meet the demands of housing and welfare that sometimes occur in a "terrifying agglomeration of people "(Jones, 1990:18). Indeed

how to feed, provide shelter, or facilitate the mobility of many people, how to collect and process solid waste and provide potable water to the inhabitants in each and every one of these cities? Would be necessary, proposed Fuchs, creative design solutions applicable to this large scale and make them economically, socially and environmentally sustainable. Such a huge task!

In the absence of planning, which is almost always the usual - rapid urbanization implies: a) reduction of environmental quality in urban air pollution, water and soil, noise, changes microclimates and loss of natural areas; b) severe degradation of the environment surrounding urban areas and ecological systems, through pressure exerted on the resources; c) inadequate public services (transport, water, sanitation , soils, social educational facilities, health) and housing, resulting in health risks and loss of quality of life; d) impacts on the most vulnerable in terms of deficiencies in food, access to water, energy and other basic goods and services, and e) a threat to environmental sustainability. Excerpted and adapted from "Geographical Research, Bulletin of the Institute of Geography, UNAM "