opportunities and examples

Abstract: Over the last decades, experts have been studying with growing concern statistics and demographic trends that show in many cities the urban population appears to be climbing up to astonishing numbers all over the world. Mega-Cities like Tokyo, Mexico City and Seoul are developing and nobody appears to be able to control their growth, nor to handle their impact on basic resources like water and land. The housing demand of an aging society further stimulates excessive urban sprawl. On the other hand, according to recent studies many cities expose a tendency of shrinking, from California to Japan, from Finland to the Cape of Good Hope. Shrinking cities are reported from all over the world and again it appears difficult to deal with this recent phenomenon and its impacts on our society. In times of global markets and local bottlenecks, cities change constantly and rapidly, much faster than they used to do even in the boom-days of industrialisation. Changing cities have a strong impact on both, economy and ecology. The metamorphosis of urban spaces usually degrades the environment and exhausts the resources. However, changing cities also offer chances, not only to architects and investors but also to new forms of land and resource management. In this paper the issue of growing cities and shrinking cities will be discussed. Special attention will be given to the geotechnical challenges of contracting cities. Examples from regions characterized by post-industrialization and post-socialism are presented and strategies to stimulate a sustainable urban renaissance that respects geo-resource