Even metropolitan areas that are losing population, such as Pittsburgh, are spreading out into surrounding rural areas. When suburban development displaces natural habitats, regardless of whether it is a desert in Nevada, a forest in Maine, or wetlands in Florida, plant and animal species are lost, the ability of the earth to absorb carbon dioxide is diminished, the ability of the land to absorb rainwater is reduced, and watercourses become polluted with runoff from roads and parking lots. When suburban development displaces agricultural land, natural habitats are still destroyed because agricultural production moves elsewhere. The economic health of urban areas is dependent on the presence of good quality transit and a well-designed urban fabric. Every town and city in the US has suffered to some extent from urban decay.
Urban decay takes many forms.
Historic buildings suffer from neglect and eventually crumble, or are demolished to make way for parking lots. Downtowns that were once the focus of towns and cities become deserted, and neighborhoods that once were once pleasant places to live become dilapidated and crime-ridden, housing only those who can't afford to move out. These people, the inner-city poor, and probably the biggest victims of the suburban system. For people living in suburban areas, individual car ownership is compulsory. Without a car, it is impossible to access employment, shopping, recreational activities, even school.