23 de agosto de 2012

Urban sprawl in Europe – identifying the challenge


(reviewed paper)


In Europe, research on urban sprawl is largely limited to case studies of selected metropolitan areas in a national context. In addition, the literature to date does not present comprehensive empirical evidence as to what exactly constitutes urban sprawl. Accordingly, the European Environment Agency describes urban sprawl as the “The ignored challenge” in the subtitle to its 2006 report on urban sprawl (European Environment Agency, 2006). This article aims to deliver a contribution for identifying the “challenge”: it provides a consistent overview for the area-wide distribution and characterisation of urban sprawl in Europe, based on CORINE land cover data and a set of GIS-based indicators. The indicators are built upon a framework that allows for the differentiation of distinct types of urban sprawl, including measures that compare land cover change over time. The results are presented as continuous maps of Europe for different indicators of urban sprawl, and interpreted in the context of their characteristics and distribution.



4.1 Data
4.2 Indicators
4.3 Methodology


Figure 7 summarises the two impact dimensions we have discussed in this paper. Each of the indicators contributed with its most urban sprawl- or growth-like features towards the classification in this map. According to this, surface sprawl / growth is particularly evident in Spain, Greece, and The Netherlands. Pattern sprawl is significant in the Benelux countries, in some areas of England, Germany, France, Poland, Austria, and Hungary. Overall, we identify these areas to be risk areas for urban sprawl for future research to focus upon.


Our maps presented in chapter 5 display areas with an “above average risk” of adverse land use related impacts. Areas with a high share of urban land experience significant hydrologic and mesoclimatic changes (excessive urban runoff, heat island effects) due to the spatial concentration of impervious surfaces. These areas are also characterized by a scarcity of valuable open space – both in absolute terms and per capita – and a quantitative loss of prime agricultural land and wildlife habitats. Regions or subregions with an irregular, dispersed and discontinuous urban form may be affected by a reduced efficiency of public transport systems and urban infrastructures (roads, water supply, sewer systems) and a higher per capita energy consumption (as an effect of larger travel distances). Furhtermore, areas with significant “pattern sprawl” as indicated in figure 7 witness higher risks of threats to endangered species due to landscape fragmentation and the high level of habitat disturbance.

At the same time, our analysis depicts “success stories” of implementing sustainable land use policies across the European Union. Examples refer to the relatively compact urban form and growth in parts of The Netherlands and the United Kingdom notwithstanding a high level of population density and urbanisation in both countries. Figure 3 gives evidence of a significant South-North divide in the use of ecologically sensitive areas for urban purposes. More effective or established landscape planning schemes and higher standards of environmental impact assessement in Northern Europe may explain this observation.
Furthermore, the relatively low degree of urbanisation in large parts of Scandinavia, Spain, Greece, Scotland, Ireland and southern Italy must be seen as an important ecological resource to be carefully managed in the future.

The measurement concept presented in this paper creates a methodological framework for evaluating the success of future land use policies and landscape protections programs. We deliberately avoided developing a composite sprawl index that aggregates the impact dimensions discussed above. The problem we see is that different sprawl indicators tend to outweigh each other in the process of aggregation. Therefore we recommend the use of dimension related sprawl types attributed with a specific profile of environmental and economic problems (see figure 7). Taking this into account, type-specific anti-sprawl strategies and instruments could be implemented.


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