Urban sustainability assessment is often based upon the so-called 3 pillars of economic, social and environmental, and (certainly in Australia) seems heavily weighted in terms of environmental criteria such as 'carbon neutral' and 'green'. I was involved in research that sought to move way from these traditional 3 domains and reframe indicators to better address social concerns. This involved integrated sustainability assessment under a new typology encompassing indicators related to equity, accessibility, amenity, as well as environmental performance.

In terms of methodology, it may be argued (to be inclusive) that communities and citizens themselves should make a 'methodological choice' (as Napoleon states) regarding the set of performance/assessment criteria that are important to them. But such 'tailor made' approaches make it difficult to compare and benchmark cities and towns. I am unsure how to solve this quandary. 

Dear David,

Thank you for sharing your comments. In fact, there are several ways to assess urban sustainability. I found up to 41 different methods to generate a sustainability index in my literature review ! Now, the main hypothesis I wanted to discuss is that : No matter which method is used to assess urban sustainability, the most sustainable cities will consistently stand out. In other word, if a city is really "sustainable" (so do speak), it will always stand out using any assessment methods (I could include your new approach in my analysis). If such hypothesis is verified, it would have important implications: i) it would mean that urban sustainability assessment methods have evolved over the time and are now more reliable than ever; ii) reaching a consensus would not be an important issue anymore because most of the existing approach would lead to similar conclusions; iii) the research focus of the last two decades in urban sustainability would shift from a debate on how to assess sustainability to an emerging debate on why are some cities more successful than others?

Best,

Juste

Having said that "some cities are more sustainable than others" implies that one has reliable, agreed upon, set of indicators to quantify cities sustainability. Which is not the case.

The city without waters and lots of greenery automatically belongs to different set of sustainability criteria than one with abundant amounts of waters and greenery. Therefore, sustainability comparisons are questionable.

Methodology that will determine sustainability potentials for any city, has to be based on comprehensive, systematic, integrative approach. Once potentials established they have to be quantified and ranked on a basis of local policy and needs. Than applied.

Subsequent hypothetical question: Do we really need to compare these results with others?

You might find large variety of formalisation (methodologies, methods, techniques) which support sustainable assessment. However, the local community have to be involved in the methodology selection also taking into account regulatory issues on city or national level. See some discussion about this topic in doi:10.1016/j.energy.2014.10.089

Fascinating discussion, and thanks for explaining your hypothesis further, Juste. Yes, some cities may consistently stand out when assessed using different methods (maybe these are the ones using the comprehensive, integrative approach that Ranko mentions).

However, a problem is that some cities promote themselves as 'sustainable' when analysis may reveal this is only based on some narrow criteria (e.g. green practices) while neglecting (say) social and affordability criteria. This may indicate that some urban sustainability measures (e.g. more comprehensive ones) are more reliable than others, and that we need to compare results of different methods (Ranko). But your research results would be interesting, to see whether different methods really do lead to similar conclusions (which I doubt). Taking Atom's point, local community may have very different view on whether their city is sustainable or not than the local municipality or central government.

At a more micro level, the same question arises in assessing sustainability of buildings. Another current discussion is about whether building sustainability rating systems (e.g. for eco or green buildings) sufficiently account for social sustainability. I feel there is still widespread confusion about how to assess sustainability, but your research will throw a very necessary light upon this question.

Since sustainabilty has a broad meaning one should first define whether to talk about sustainabilty in  the frame of economic, social or environmental context. Then wheter to talk about sustainability of multymilion cities or cites  let say from 50.000 to 300.000 inhabitants. And even then there will be no single solution for sustainabilty in cities. Each one can offer the opportunity to define and interpret one,s own priorities.   

A great book on the subject is Towards an Urban Rena issance-Final Report of the Urban Task Force chaired by Lord Rogers of Riverside, 1999.

Hi Juste

Exactly which cities 'consistently stand out and outperform the others no matter how their sustainability is measured'?

i am very intrigued by your literature review on urban sustainability methodology, especially with respect to quantitative methodologies that surpass the ambit of 'liveability' surveys.  Are you able to provide a citation?

It would seem that urban sustainability, to be measured, would have to have a time component or duration for which continued existence can be predicted, and after which non sustainability would contribute to collapse--assuming other factors, such as destruction in war, epidemic, or natural disaster, do not intervene.  

Without such a time frame, can any existing urban settlement be considered unsustainable if it exists and operates?  

Not having a ready answer to this question, but interested in your response with respect to my own work in urban design, i ll look forward to hearing from you.

Just wondering why nobody mentioned http://www.starcommunities.org/ - this is very comprehensive and aims at comparing sustainability between cities. At least it's relevant for someone from Montreal since the city is also trying to use this methodology,

If different methods of assessing yield different results, then, how objectively can we say the assessments are? Since the concept of sustainability may be viewed differently by different stakeholders, it may be important to state from inception, the criteria used for the sustainability measure. In this way, when we say that a city is sustainable, then, we can tell in whose eyes, such a conclusion comes from ....is it from the residents, the local authority or some NGO, and if so, what was their criteria in the measurement, to arrive at their conclusion. 

 Thank you for sharing Martin and Saeed,

You raised a very good point. In an upcoming paper, I will compare different methodologies for assessing urban sustainability (Martin: Perhaps, including STAR approach) on one sample of cities to estimate the extent to which different approaches lead to different outcomes. We argue that as knowledge and urban sustainability assessment approaches evolve and improve over time, recent approaches are likely to lead to results showing less disparity, more common patterns and similar characteristics. We will test our hypothesis and we will take it from there! Thank you again for sharing.

Dear Juste,

The city sustainability assessment result should first try to establish is the observed city component sustainable, why it is not sustainable and/or not sustainable enough. To be able to have that result we should first develop sustainability indicators for each city component, than agree on desired sustainability level of quality for each and finally produce benchmark for each. Martin has presented ranking system that is very comprehensive, apparently excellent attempt to establish referent benchmarks. The question is: has it analyzed, identified potentials and included interactions & synergies that might significantly change the sustainability result. We think this is the approach that has to be investigated.