natural elements. This portrays the need for assessment and decision support tools
that can model complex relations and integrate the multiple benefits of NBS to
effectively support their use in addressing urban challenges.
3 Urban Scale LCA for the Evaluation of NBS
3.1 Life Cycle Assessment (LCA) and Urban
Metabolism (UM)
As stated earlier, urban activities are among the major sources of sustainability
issues, in particular global climate change; yet, they are also highly vulnerable to
the effects of such issues. Through utilization of various assessment tools ranging
from indicators to complex models, urban sustainability assessment provides
insight to the current state of the environment, causes of environmental impacts,
hotspots among these causes, which ultimately lead to performance evaluation of
initiatives and policies for sustainable urban development [13]. Consequently, it is
imperative to conduct sustainability assessment for monitoring and measuring the
past or current environmental pressures, states, or impacts of urban areas. Urban
assessments help cities to identify main bottlenecks regarding resilience, vulnerability to climate change, food, water and energy security issues and develop sound
strategies or policies to tackle them.
LCA is a holistic methodology capable of revealing a broad range of environmental impacts in a systematic way and has been widely used for urban sustainability assessment [17]. Through LCA, it is possible to go beyond inventorying
direct consumption and emissions, and consider transboundary or cross media
effects embedded in urban flows and stocks. Of course, this is only possible by
means of reflecting the complexity of urban systems, which are comprised of layers
of sub-systems in LCA system models.
NBS are among the strategies that can benefit from such a holistic assessment
due to their utility under themes including greenhouse gas emissions, biodiversity,
water, urban food, air and health [14]. Moreover, LCA is also suitable to address
the multi layered nature of NBS as it covers various environmental mechanisms
revealing information on different impacts at different scales that apply to mid-point
and end-point results.
To be able to reach the desired level of representation of complex urban systems,
the conceptual models developed during system boundary definition stage of LCA
can benefit from the urban metabolism (UM) approach. This is a good foundation
for identifying the relevant urban flows within the system boundary and their
interactions. The UM approach is based on an analogy for the resource consumption and waste generation of cities, resembling the requirement for nutrient
296
D. Başoğlu et al.
that can model complex relations and integrate the multiple benefits of NBS to
effectively support their use in addressing urban challenges.
3 Urban Scale LCA for the Evaluation of NBS
3.1 Life Cycle Assessment (LCA) and Urban
Metabolism (UM)
As stated earlier, urban activities are among the major sources of sustainability
issues, in particular global climate change; yet, they are also highly vulnerable to
the effects of such issues. Through utilization of various assessment tools ranging
from indicators to complex models, urban sustainability assessment provides
insight to the current state of the environment, causes of environmental impacts,
hotspots among these causes, which ultimately lead to performance evaluation of
initiatives and policies for sustainable urban development [13]. Consequently, it is
imperative to conduct sustainability assessment for monitoring and measuring the
past or current environmental pressures, states, or impacts of urban areas. Urban
assessments help cities to identify main bottlenecks regarding resilience, vulnerability to climate change, food, water and energy security issues and develop sound
strategies or policies to tackle them.
LCA is a holistic methodology capable of revealing a broad range of environmental impacts in a systematic way and has been widely used for urban sustainability assessment [17]. Through LCA, it is possible to go beyond inventorying
direct consumption and emissions, and consider transboundary or cross media
effects embedded in urban flows and stocks. Of course, this is only possible by
means of reflecting the complexity of urban systems, which are comprised of layers
of sub-systems in LCA system models.
NBS are among the strategies that can benefit from such a holistic assessment
due to their utility under themes including greenhouse gas emissions, biodiversity,
water, urban food, air and health [14]. Moreover, LCA is also suitable to address
the multi layered nature of NBS as it covers various environmental mechanisms
revealing information on different impacts at different scales that apply to mid-point
and end-point results.
To be able to reach the desired level of representation of complex urban systems,
the conceptual models developed during system boundary definition stage of LCA
can benefit from the urban metabolism (UM) approach. This is a good foundation
for identifying the relevant urban flows within the system boundary and their
interactions. The UM approach is based on an analogy for the resource consumption and waste generation of cities, resembling the requirement for nutrient
296
D. Başoğlu et al.