84
H. Nuissl and S. Siedentop
prosperous and dynamic societal development without any kind of “land consumption”—particularly in economically growing nations (e.g. Deng et al. 2010). The
dispute on whether urban land use change is a curse or a blessing is not only one
about the prioritisation of goals, but also includes a fervent academic debate about
the validity of countless empirical findings on its adverse impacts. Critics mark these
findings as well as the methodologies with which they were obtained, as largely ideological, i.e. based on the normative assumption that urban land use change should be
contained. This kind of criticism, put forth in defence of laissez-faire urbanisation,
however, usually appears at least as “ideological” as the criticised studies.
The scholarly debate about the impacts of urbanisation and urban land use change
has become almost incomprehensible. However, it is possible to distinguish a few
major threads of debate each of which emphasises a particular issue of concern. First
of all, there are major concerns regarding the environmental outcomes of urban land
use change. These impacts are largely related to changing land cover, i.e. the sealing of
land, which almost inevitably occurs when land is being developed (Johnson 2001;
Pauleit et al. 2005). In other words: urban land use change leads to an increased
share of artificial, impervious surfaces, including built-up land, i.e. rooftops, roads,
parking lots, pavements, etc. (Arnold and Gibbons 1996; Haase and Nuissl 2007).
Imperviousness physically limits the infiltration of rainfall into the ground. Rainfall
and snowmelt that is unable to infiltrate instead must become surface runoff (Alberti
1999). Thus, soil sealing in highly urbanised areas is widely viewed as an important causal factor for flood risks (Frenkel 2004). Due to the fact that urban runoff
water carries with it chemical pollutants (e.g. from automobile traffic or industrial
land uses), imperviousness also contributes to the biochemical degradation of water
resources. Based on many empirical studies, Moglen and Kim (2007) estimated that,
once the rate of paved surfaces exceeds a threshold of 10–15%, various indicators of
biological stream quality begin to markedly decrease. Moreover, the spatial concentration of artificial land cover with specific thermal characteristics also creates local
temperature anomalies. This leads to a higher average temperature in the dense urban
fabric compared to the urban periphery (“urban heat island”) (Voogt 2002; Watkins
et al. 2007).
In addition to the magnitude of urban land use change, its spatial pattern has
also to be taken into account. Dispersed and fragmented land use patterns are a
crucial contributor to landscape fragmentation, which is characterised by a process
of perforation, dissection and isolation of habitat areas and natural or semi-natural
ecosystems (Jaeger 2000). Thus, many scholars have regarded urban land use change
as a major cause of the alarming loss of species all over the world (Theobald et al.
1997; Cieslewicz 2002).
The overall impact of urban land use change not only depends on the environmental “quality” of resulting land use patterns. Indeed, the characteristics of the land
(e.g. soil quality, habitat quality, vegetation, etc.) that became urbanised within a
specific period of time also have to be examined from an economic perspective. One
particular concern is the loss of prime agricultural land, which has major importance for the long-term competitiveness and sustainability of agriculture generally
(Hasse and Lathrop 2003). The European Environment Agency (EEA 2005: 176)
H. Nuissl and S. Siedentop
prosperous and dynamic societal development without any kind of “land consumption”—particularly in economically growing nations (e.g. Deng et al. 2010). The
dispute on whether urban land use change is a curse or a blessing is not only one
about the prioritisation of goals, but also includes a fervent academic debate about
the validity of countless empirical findings on its adverse impacts. Critics mark these
findings as well as the methodologies with which they were obtained, as largely ideological, i.e. based on the normative assumption that urban land use change should be
contained. This kind of criticism, put forth in defence of laissez-faire urbanisation,
however, usually appears at least as “ideological” as the criticised studies.
The scholarly debate about the impacts of urbanisation and urban land use change
has become almost incomprehensible. However, it is possible to distinguish a few
major threads of debate each of which emphasises a particular issue of concern. First
of all, there are major concerns regarding the environmental outcomes of urban land
use change. These impacts are largely related to changing land cover, i.e. the sealing of
land, which almost inevitably occurs when land is being developed (Johnson 2001;
Pauleit et al. 2005). In other words: urban land use change leads to an increased
share of artificial, impervious surfaces, including built-up land, i.e. rooftops, roads,
parking lots, pavements, etc. (Arnold and Gibbons 1996; Haase and Nuissl 2007).
Imperviousness physically limits the infiltration of rainfall into the ground. Rainfall
and snowmelt that is unable to infiltrate instead must become surface runoff (Alberti
1999). Thus, soil sealing in highly urbanised areas is widely viewed as an important causal factor for flood risks (Frenkel 2004). Due to the fact that urban runoff
water carries with it chemical pollutants (e.g. from automobile traffic or industrial
land uses), imperviousness also contributes to the biochemical degradation of water
resources. Based on many empirical studies, Moglen and Kim (2007) estimated that,
once the rate of paved surfaces exceeds a threshold of 10–15%, various indicators of
biological stream quality begin to markedly decrease. Moreover, the spatial concentration of artificial land cover with specific thermal characteristics also creates local
temperature anomalies. This leads to a higher average temperature in the dense urban
fabric compared to the urban periphery (“urban heat island”) (Voogt 2002; Watkins
et al. 2007).
In addition to the magnitude of urban land use change, its spatial pattern has
also to be taken into account. Dispersed and fragmented land use patterns are a
crucial contributor to landscape fragmentation, which is characterised by a process
of perforation, dissection and isolation of habitat areas and natural or semi-natural
ecosystems (Jaeger 2000). Thus, many scholars have regarded urban land use change
as a major cause of the alarming loss of species all over the world (Theobald et al.
1997; Cieslewicz 2002).
The overall impact of urban land use change not only depends on the environmental “quality” of resulting land use patterns. Indeed, the characteristics of the land
(e.g. soil quality, habitat quality, vegetation, etc.) that became urbanised within a
specific period of time also have to be examined from an economic perspective. One
particular concern is the loss of prime agricultural land, which has major importance for the long-term competitiveness and sustainability of agriculture generally
(Hasse and Lathrop 2003). The European Environment Agency (EEA 2005: 176)