‘This is a wonderful book that should be on the desk of every architect and planner. It shows how

Do quantitative approaches really militate against diverse natural systems?
Arguably yes. Many tools are based on life-cycle analysis (LCA), which aggregates the impacts at 
each step in the production process. Building rating tools based on LCA help us to quantify impacts 
at each separate stage of the life of the project, to reduce materials, energy, and emissions or waste.
This is a very useful way to improve upon an existing process, or help us to make choices between 
existing products. But this reductionist framework tends to segregate factors that are inseparable, such 
as human and environmental health.
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Such a framework also diverts attention from 
total
stocks and 
flows of materials and energy. It instead encourages adherence to given design templates derived from 
typical walls, roofs and/or boxes. Complicated processes for comparing and aggregating components 
of buildings can themselves obscure opportunities for creating more equitable environments and 
whole system synergies [Box 31]. For example, the author has seen many debates about whether 

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Building Rating Tools
bricks or concrete walls, or wool or cellulous insulation, have more adverse impacts. Being focused 
on either/or comparisons, people forget to consider organic materials or other forms of insulation 
combined with living walls or vertical wetlands. Conversely, when people measure the resource 
efficiency of double skins, they forget to measure their contribution to the urban heat island effect.
Although natural systems are variable and hard to predict, measure and compare, they are easy to 
adapt after construction if they fail to perform well. For example, we can easily adjust the thermal 
mass, insulation or shading of low-cost organic materials.
How do we ensure LCA-based tools work to support whole systems design?
To do so, designers need to be aware of the assumptions and values embedded in the design of the 
tools. We have already mentioned how formulas begin with standard buildings conceived as boxes 
and discriminate against natural systems. Another example is that LCA uses ‘normalization’ processes 
to put entirely incommensurate impacts on the same scale, such as biodiversity impacts and global 
warming. This is in order to assign numbers for comparison purposes. Some incommensurable 
issues in life-cycle considerations include:
•
Sources, including how (eg mining or herbicides used) and where (eg valuable habitats)
• 
Species and ecosystems affected (eg stream flow and quality)
• 
Renewable fuels and materials (eg growth rate of timber)
• 
Impacts of production (eg life-system costs and impacts on workers)
• 
Energy used (eg transport of products and workers)
• 
Longevity (eg reusability and composting)
• 
Machinery and fuels involved in production (eg upstream fossil fuels)
• 
Toxins and chemicals (eg global warming and worker health)
• 
Operating energy and efficiency (eg insulation value)
• 
Companion products that may be used (eg toxic components)
• 
Mitigation (eg ecological restoration)
• 
Reuse and disposal (eg landfill and incineration) 
• 
Management systems (in the forest and the factory)
Incommensurables lead to tradeoffs. Tradeoffs are thus ‘designed in’ to most decision and design 
tools. They are an indicator of sub-optimal solutions – not whole systems rationality.