A Review of Urban Sustainability Assessment Methodologies

Abstract

S ustainability has emerged as a planning concept from its beginnings in economics and ecological thinking and has widely been applied to urban development. Urban sustainability is simply described as a desirable state or set of urban conditions that persists overtime. Just as the task of defining sustainability has progressed in response to early economic thinking, so has the task of its assessment. Many urban sustainability assessment methods can be identified from literature. However an examination of these methods reveals largely three methodological foundations. Focusing on the context of urban development, this paper presents an appraisal of the relative potentials and limitations of methods developed around the three identified methodological foundations. The paper agrees with the much held view that, most currently available urban sustainability assessment methods fail to demonstrate sufficient understanding of the interrelations and interdependencies of social, economic and environmental considerations. It further points to a wide gap between assessment theories and practices. To help narrow this rather wide gap, the paper recommends a pragmatic shift in focus, from theory development to application and auditing. A suggestion is made for the application of key assessment methods in a given urban area and across various issues, spatial and time scales so as to allow for method comparison. It is hoped that the parallel application of existing methods will greatly accelerate the urban sustainability assessment learning process and will help in the improvement of both theory and practice.

Full text

International Conference on Whole Life Urban Sustainability and its Assessment
M. Horner, C. Hardcastle, A. Price, J. Bebbington (Eds)
Glasgow, 2007
A Review of Urban Sustainability Assessment Methodologies
Emmanuel Adinyira a,*, Samuel Oteng-Seifah b, Theophilus Adjei-Kumi c
a,*,b,c Department of Building Technology, Kwame Nkrumah University of Science and Technology,
Kumasi, Ghana.
ABSTRACT
Sustainability has emerged as a planning concept from its beginnings in economics
and ecological thinking and has widely been applied to urban development. Urban
sustainability is simply described as a desirable state or set of urban conditions that
persists overtime. Just as the task of defining sustainability has progressed in
response to early economic thinking, so has the task of its assessment. Many urban
sustainability assessment methods can be identified from literature. However an
examination of these methods reveals largely three methodological foundations.
Focusing on the context of urban development, this paper presents an appraisal of
the relative potentials and limitations of methods developed around the three
identified methodological foundations. The paper agrees with the much held view
that, most currently available urban sustainability assessment methods fail to
demonstrate sufficient understanding of the interrelations and interdependencies of
social, economic and environmental considerations. It further points to a wide gap
between assessment theories and practices. To help narrow this rather wide gap, the
paper recommends a pragmatic shift in focus, from theory development to application
and auditing. A suggestion is made for the application of key assessment methods in
a given urban area and across various issues, spatial and time scales so as to allow
for method comparison. It is hoped that the parallel application of existing methods
will greatly accelerate the urban sustainability assessment learning process and will
help in the improvement of both theory and practice.
Key words: Assessment Methods, Review, Urban Sustainability.

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1 INTRODUCTION
Sustainable development as a concept has been gaining increasing popularity across
various sectors since the Brundtland Commission Report in 1987 (WCED, 1987).
This report captioned, Our Common Future, is taken as a starting point for most
current discussions on the concept of sustainable development. However, it is neither
the starting point nor the possible end of the conceptual development process.
Sustainability has emerged as a planning concept from its beginnings in economics
and ecological thinking and has widely been applied to urban development. Urban
sustainability is seen as a desirable state of urban conditions that persists overtime. It
is often characterised by issues such as inter-generational equity, intra-generational
equity, protection of the natural environment, minimal use of non-renewable
resources, economic vitality and diversity, community self-reliance, individual well-
being, and satisfaction of basic human needs.
As the task of defining sustainability progressed in response to early economic
thinking, so did the task of its assessment. Ever since sustainable development
became the catchword in most international discussions, several approaches to its
assessment have been developed. According to Lawrence (1997), sustainability
assessment is simply applying the broad principles of sustainability to ascertain
whether, and to what extent, various actions might advance the cause of
sustainability. The term “Sustainability Assessment” is used in both literature and
practice in two very different contexts. Firstly, it is used in the context of checking if a
community or organisation is progressing towards sustainability. Here, it serves as an
auditing or performance testing system. In the second context, it serves more as
impact assessment processes in that it attempts to assess the sustainability of
proposed projects, plans, policies or legislation before they are implemented
(Devuyst, 2000).
Over the past half-century, much effort in a variety of disciplines has been made at
developing approaches to sustainability assessment. Efforts have ranged from
assessing change that pushes beyond an emphasis on economic signals to more
complete treatment of human and ecosystem well-being (Hodge, 1997). Much of the
literature and theory surrounding sustainability assessment have argued that current
assessment methods often fail to involve sufficient vision and understanding of the
interrelations and interdependencies of social, economic and environmental
considerations. This paper thus seeks to contribute to the urban sustainability
assessment debate by reviewing the underlining methodologies for the major
assessment methods identified and present their potentials and limitations.

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2 REVIEW FRAMEWORK
In carrying out a comprehensive review of identified methodologies, a review
framework that allows for the involvement of most issues relevant to sustainable
urban development was employed. For each methodology, issues such as the origin
and status of the methodology from well established to experimental were looked
into. As part of the review, various assessment methods developed on the basis of
the identified methodologies were appraised. The data requirements of these
methods and their application to urban developmental activities such as planning,
property development, design, construction and operation were looked into. This
allowed for the strengths, weaknesses, potential applications, data inputs, outputs
and applicability at various spatial scales for the various methods to be identified.
3 ASSESSMENT METHODOLOGIES
Many urban sustainability assessment techniques can be identified from literature. A
recent review of urban sustainability assessment techniques conducted using the
built environment quality evaluation for sustainability through time (BEQUEST)
framework, revealed several methods available for sustainability assessment of
urban activities (Deakin et al, 2002; Ugwu and Haupt, 2005). However a careful
examination of existing assessment methods point to notably three groups of
methods when grouped on the basis of their methodological foundations. These are
namely; ‘environmental in general’ methods, Life cycle assessment methods and
sustainability indicator assessment methods.
3.1 ‘Environment in general’ methods
Sustainability assessment methods based on environmental assessment dates back
to the pre-Brundtland era where sustainability mainly focused on environmental
issues such as resource consumption, pollution and impact on bio-diversity. Across
the range of urban activities, the environmental dimension of sustainable
development has greatest coverage. With this methodology, environmental impacts
tend to be identified mostly using methods such as checklists or matrices and
evaluations carried out using methods such as logical framework, cost-effectiveness
analysis and multi-criteria assessments. Resources consumption, pollution and
environmental valuation, under various building scales, urban forms and policy plans
are given prominence under this methodology. Environmental valuation methods
such as cost-benefit analysis, contingent valuation, hedonic pricing and the travel
cost methods all have environmental assessment as their methodological foundation.
On the basis of this methodology, many sustainability assessment methods that
focus on energy and material flow and address both resources use and waste arising
across a wide range of urban activities have been developed.

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A careful look at ‘environment in general’ methods of sustainability assessment
reveals rather significant limitations with respect to the range of sustainability issues
they are capable of addressing. They are mostly limited to applications at the levels
of policy planning, programme development and urban design (Guy and Marvin,
1997; Brandon et al, 1997). In view of the rather minimal coverage of urban
development activities by ‘environment in general’ methods of urban sustainability
assessment, they have lost their appeal. (Brandon et al, 1997; Bergh et al, 1997;
Nijkamp and Pepping, 1998).
3.2 Life Cycle Assessment methods
The origin of life cycle assessment methods can be traced to after the Agenda 21’s
call for the integration of environment and other aspects of urban development such
as the social, economic and institutional issues (UNCED, 1992). This resulted in a
shift of focus in method development from environment evaluation to life cycle
assessment (LCA). LCA methods attempts to address broader sustainability issues
such as environmental limits, social equity concerns and the need for stakeholder
participation. They are based on a structured methodology that can be utilized to
evaluate impact of urban development across their life cycle.
In comparison to ‘environmental in general’ methods, LCA methods appear to
address a much broader range of urban activities and scales. This can be attributed
to the fact that they focus on both social and economic issues of urban development.
LCA methods attempt to address social and economic issues as well as
environmental issues, but they fail to integrate all this in one assessment. They often
address social or economic issues using approaches from the earlier ‘environment in
general methods (Bizarro and Nijkamp, 1997). LCA methods are seen as methods
based on a well established and standardized methodology (Sahely et al., 2005).In
spite of this, LCA methods still show a limitation with respect to the range of
sustainability issues they are able to address. They are seen not to perform well with
respect to social and institutional issues of urban development. Some major
weaknesses of such methods include complex and time-consuming nature of
analysis, and large data requirements. Furthermore, LCA methods fail to integrate
environmental, economic and social aspects of the task of urban sustainability
assessment. This notwithstanding, LCA methods have contributed significantly to
sustainability assessment by widening coverage of urban activities and spatial
scales.

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3.3 Sustainability Indicator methods
With sustainability assessment, there is the need to integrate issues and seek their
cumulative and synergistic impact on the environment. How environmental, social
and economic information is analysed, integrated and presented to decision-makers
is the most critical concern of sustainability assessment. Methods developed on the
basis of ‘environment in general’ and the LCA methodologies have all in one way or
the other failed to achieve this requirement. ‘Environment in general’ methods,
focused on environmental issues with policy, programme and infrastructure provision
and LCA methods attempted to address social and economic issues in addition to
environmental concerns, but in a piecemeal manner. In view of this, a third
methodology that seeks to achieve integration of all issues of sustainability has
gradually evolved. This methodology employs a wide range of indicators to
characterise the different dimensions or aspects of urban development. Under it, the
assessment of sustainability is actually considered as an assessment of indicators by
which people can track their progress towards sustainability.
Sustainability indicators are seen as an essential component in the overall
assessment of progress towards sustainable development. They are useful for
monitoring and measuring the state of the environment by considering a manageable
number of variables or characteristics (McLaren and Simonovic 1999). Several
studies at the urban, regional, and national levels have compiled extensive lists of
sustainability indicators (Foxon et al. 2002; Hellström et al. 2000; Alberti 1996;
Maclaren 1996). From these, many assessment methods have been developed
which attempt to simplify the holistic assessment of urban sustainability. Such
methods rely on key interactions and feedback mechanisms between infrastructure
and surrounding environmental, economic, and social systems and uses
sustainability criteria and indicators as a way of understanding and quantifying such
interacting effects.
From a methodological standpoint, sustainability indicator methods are recognised as
useful integration tools to evaluate a situation in several dimensions and to test
sustainability. The main problem with such methods however, is relating what the
indicators measure to actual sustainability. Sustainability indicators are not useful
when considered in isolation, but rather their usefulness comes from monitoring
relative changes in the state of the environment. The use of sustainability indicator
methods of assessing urban sustainability has had mixed results in practice and, in
some cases, minimal effects on policy (Levett, 1998).They are unavoidably value-
laden, and sometimes present difficulties in interpreting whether or not any progress
towards sustainability is actually being made.

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4 CONCLUSIONS AND RECOMMENDATIONS
The primary object of any urban sustainability assessment exercise is to provide the
opportunity for more inclusive and informed decision-making regarding issues of
urban development. Thus the ability to address economic, social and environmental
interdependencies within policies, plans, legislations and projects has become the
basic requirement of all urban sustainability assessments methods. A look at the
development of urban sustainability assessment methodologies reveals a steady
progress toward achieving this requirement. Much of this improvement can be put
down to attempts at addressing the limitations of the pre-Brundtland assessment
methodologies. The evolution of methods that attempt to holistically assess the
impact of development across most urban spatial scales can be traced to much
recent methodologies. In spite of this, most currently available methods still fail to
demonstrate sufficient understanding of the interrelations and interdependencies of
social, economic and environmental considerations. Many reports on sustainability
assessment methods points to the absence of truly integrated urban sustainability
assessment methods. It is the view of this paper that further improvement in
assessment methods can only be achieved when existing methodologies a critically
reviewed and further research into methodological improvement carried out.
One major shortfall of current developments in the area of urban sustainability
assessment is the relative lack of implementation of developed methods. As
demonstrated in this review, much progress has been made in the improvement of
urban sustainability assessment theories. However, a wide gap still exists between
assessment theories and assessment practices. Cooper (1997; 1999) alludes to this
fact and states that the practice of assessment lags well behind development of
theories. New assessment methods remain largely experimental with relatively few
applications in practice. An amble demonstration of this is the current situation where
most assessment methods in widespread use fail to make assessments that
adequately address most issues underlying the sustainable urban development
process. To improve on the present situation, there is the need to identify those
aspects of urban activities and issues at various spatial scales which are poorly
covered by available assessment techniques. On the basis of the gaps identified,
cross-fertilisation of methodologies can then be employed to develop methods which
will be capable of addressing most if not all urban activities and spatial scales. The
paper further recommends a pragmatic shift in the focus of urban sustainability
assessment from theory development to more of application and auditing. Methods
must quickly move beyond the experimental phase to practical application. A
suggestion is thus made for major assessment methods developed to be used in
assessing urban sustainability over a given urban area and across the various
issues, spatial and time scales so as to allow for method comparison. This parallel
application of existing methodologies will greatly accelerate the urban sustainability

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assessment learning process and will help in the improvement of both theory and
practice.
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