The 5th International Conference of the International Forum on Urbanism (IFoU) 2011 National University of Singapore, Department of Architecture Global Visions: Risks and Opportunities for the Urban Planet INTERVENTIONS IN CONTEMPORARY URBAN SITUATIONS Kees Christiaanse The above title contains two words that play a key-role for understanding the operation of urban design and planning as a pro-active force with a concrete impact. “Intervention” indicates that influence on urbanization in general is exerted by targeted actions within a limited field, and “Situation” indicates that any given urban condition is a transient and dynamic balance between the forces of the moment. Today, there exists a general consensus about the fact that the city does not let itself be designed but merely steered in a limited way. The production of built environment takes place according to precise rules, consisting of natural processes and man-made conventions and regulations, of which economic drivers and consequently the stocks and flows of people, goods and information are predominant. However, many examples of big interventions, I call them “grands projèts”, can be found in the history of urbanization, showing that the conscious exertion of influence by man on his built environment can reach considerable degrees of control. We cannot only see this in Hausmann‟s Paris or the European high-speed rail network, but also in the self-conscious development of an island like Singapore (Fig 1). Fig 1 Singapore, Santosa construction Site 1 It is not easy to conceive a theoretical model for contemporary urbanization - a reduced representation of a far more complex constellation of systems - as a framework for understanding. Formerly, such a model used to evolve from the history of models of urbanization and their consequent extrapolations. Today however, forms of urbanization are so complex - and at the same time global and specific - that no past model of reading the city can help us. As a result, we are increasingly dependent on fieldwork observations, as well as statistical and visual data acquisition of urbanization‟s causes and effects, in order to sketch a useful framework of understanding. If we look for example at a satellite photo of the earth by night, the cities of Western Europe light up like a galaxy of stars (Fig 2). In Europe, there are hundreds of mid-sized cities, Fig 2 Europe-map of Europe-nightlights-satellites-woodley wonderworks with populations ranging from 100,000 to 1 million inhabitants. They form a web with an average mesh opening of approximately 100 km. Within this web, 300 million people live in a relatively high-quality living environment. This condition is unique for Europe. In other parts of the world, cities are larger, lie farther apart, or form concentrated agglomerations in an otherwise thinly populated landscape. In Asia are some constellations with somewhat comparable distances, like on the island of Java or in part of Japan, their respective conditions however are radically different. There are some large metropolises in Europe – such as London, Berlin, Paris, and Madrid. However, mid-sized cities are the norm and make it justifiable to refer to a typical „European urban condition‟. These mid-sized cities and their regional networks form the basis for Europe‟s urban culture and economy. They have developed into an extended „carpet metropolis‟ (fig 3) and are functioning as a comprehensive global city that is Fig 3 Carpet Metropolis - nueterlings reasonably understood in economic and logistical terms. The understanding of how to influence the course of their development is however less clear. Polycentric agglomerations such as the Randstad (the urban belt formded by Amsterdam, Rotterdam, The Hague Utrecht in the Netherlands) and the German Ruhr area (Dusseldorf, Duisburg, Essen, Dortmund, Cologne) are often regarded as „global cities‟, comparable with London or Paris. However, an approach in which the generic European city is regarded as forming a cell within an organism on the scale of Europe as a whole, including its rural surface, provides a more clarifying model. From this perspective, European cities constitute an integrated, resilient organism that continues to function when shifts in gravitation take place or certain cells and connections drop out. The organism consists not only of the core cities themselves. Almost every city in Europe forms an agglomeration with physical and social spheres of influence that extend beyond its political and administrative borders. (Fig 4) Fig 4 Hollow Core, Rem Koolhaas The 30 million inhabitants of the region which Rem Koolhaas named „Hollow Core‟ – the (sub)urbanized area between the agglomerations of Randstad, the Flemish Diamond (Antwerp, Brussels, Gent) and the Ruhr area – live and work in an urban landscape set between core cities and are responsible for a considerable proportion of the region‟s economic production and consumption. Within an hour, residents of Hollow Core can reach four international airports, eight intercity railway stations, sixteen universities, thirty-two international sport venues, and sixty-four shopping malls, while at the same time they live in low-density neighbourhoods in a fairly green environment. More or less the same applies to the whole of Western Europe, and it represents an unparalleled quality of life. Nowhere else in the world is everything so accessible, while at the same time so „remote‟. Within this landscape, the mid-sized European cities function as symbols of regional identity, centres of culture, knowledge and education and as transport hubs for goods and people. Their peripheries overlap with those of other cities disregarding municipal, regional and national borders and form sequences that extend across hundreds of kilometers. They are not so much competitors against each other, but rather are mutually indispensable and complementary. Just as the city centre needs the periphery, these cities cannot exist without each other and the network connecting them. In the fields of economics and the social sciences, this is widely accepted as common knowledge – witness the extensive literature on the global economy, import and export flows, production and consumption patterns, and migratory movements.(Fig 5) Fig 5 Systems of Central Places, Walter Christaller, 1993 In the early thirties, the German geographer Walter Christaller was one of the first to construct an urbanization model for this condition. He illustrated his concept of the “System of Central Places” with beautiful diagrams of the interrelations and hierarchies between southern German towns, represented by circles of influence. These circles were later reflected in the famous “Potatoe-Plan” for Greater London from 1943 (Fig 6) by Sir Patrick Abercrombie. Both read the urban landscape as a hierarchical topology of centralities. They showed for the first time that these “centralities” operate complementary in their topological relations and that they are the main drivers of urbanization. The urban intensity and amenities of these central places extend beyond the local scale, becoming significant hubs, influencing spatial, economic, social and cultural development on a regional, national or even global scale. Largely differing in character, size and impact, they tend to form a hierarchical network, a topology of places, constituting the city as a manifold entity, not only in terms of identity and orientation, but also of economy, community and culture. Fig 6 Greater London, Patrick Ambercrombie, 1943 From a historical perspective, these centralities include the „city-centre“, the „market“, the „business district“, the „railway-station“, the „government quarter“, the „shopping- mall“or the „stock-exchange“. Today however, this topology of centralities has been extended with phenomena like the „creative neighbourhood“, the „airport city“, the „loft-quarter“, the „theme-park“, „the museum island“or the „science campus“. Centralities constitute the key-areas to steer intervention. Urban designers may be aware of these indissoluble connections and mutual dependencies. However, they are still quite perplexed regarding the means of controlling spatial development, and there is a sense that there are no adequate tools available with which to exert influence. This feeling of impotence is the result of well-known factors such as the fragmentation of administrative borders, the distinct and contrary competences of various authorities, the fact that urbanization processes tend to follow the dynamics of the economy (which is even less controllable), the inability of politicians to achieve consensus on a larger scale, and the resilience of structures that have resulted from long periods of historical growth. The urban landscape has become apparently chaotic, with radically different developments appearing to coexist in arbitrary ways. Essentially, however, this apparently chaotic urban landscape is extremely regulated. Almost everything that is built has been designed according to precise rules and regulations – political decisions, zoning plans, building codes, property rights, feasibility studies, financing models and programmatic scenarios. This hyper-order is reinforced by the fact that physically speaking, urban planning – apart from a few exceptions – is a fairly two-dimensional affair. Everything is neatly arranged side by side on the surface of the earth: the boundaries of individual plots do not overlap, buildings stand next to and not on top of each other, each plot has access