On this website, we often see lists of the top sustainable cities on the planet, (e.g. this one) that have been compiled by diverse organisations. But, what does sustainability mean in this context?

My book The One Planet Life contains a chapter arguing for a change in our attitude to planning, land and development to enable truly sustainable development, but prerequisite to this is a way of measuring when we have got there.

The trouble is that currently there is a paucity of validated research enabling us to determine what, in practice, actually is sustainable. Indeed, we even lack a common definition of the word, apart from the vague UN one about meeting present needs without compromising those of our descendants.

We urgently need more research on this topic. So much money is being invested on so-called 'sustainable' infrastructure and developments without any measurement of its true ecological impact.

The following is a non-exclusive discussion of various options and approaches already existing, as a way of scoping the field.

Ecological footprint analysis

At first glance ecological footprint analysis seems to offer much of what we need, but there are several definitions of this.

It originated from the Global Footprint Network, which crunches the numbers for WWF's occasional Living Planet Reports. Although a non-profit, GFN is a consultancy which sells its footprinting services. It uses publicly available data but the way it then calculates the impact of a country or city in terms of global hectares per person is obscure, because if it wasn't they wouldn't be able to sell their services. (A global hectare per person is the composite global average of an area, productivity (yield) and equivalence factor that is used as an aggregation of total impacts, which therefore means that it is open for misinterpretation and confusion by uninformed users.)

The Stockholm Environment Institute (SEI) was behind work done for the Welsh Government's calculation of Wales' ecological footprint, used as a basis for its One Wales: One Planet policy document. But the data has not been updated since 2008. To calculate EFs, SEI uses a set of spreadsheets called the Resources and Energy Analysis Programme.

The SEI came up with Reap-Petite that applies this on a smaller scale with the output being in carbon emissions, but again the methodology is not obvious.

The Welsh Government itself commissioned a small team to use SEI's data to build a separate spreadsheet that would help to determine ecological footprint at the smallest possible level, that of a household.

This micro scale involves very different calculations and assumptions to the macro level deployed by GFN. At the national level, reporting is often done on a production basis, whereas on an individual or household level it is done on a consumption basis.

The Welsh government has a stated policy aim (in One Wales: One Planet (the research behind it is here)) of aiming to only use the resources commensurate with there being one planet within one generation, but is currently working out how to get there. 

One Planet Development

The above spreadsheet is used as a planning tool in Wales to determine whether planning applications to build a home and a smallholding on agricultural land should be permitted. This is called a One Planet Development, advocated by the One Planet Council of which I am a patron. Applicants must satisfy the requirement that within five years the ecological footprint would be reduced to 1.88 global hectares per person.

In this case, household expenditure is used as a proxy for ecological footprint. But, again, the data and the methodology behind the spreadsheet are old and obscure.

The One Planet Development policy allows for the possibility of edge-of-settlement One Planet Developments but these are not defined. The One Planet Council has begun work on a definition which would also enable towns, villages and even cities to work towards declaring an aim to become a One Planet Town or City. 

One Planet Cities

One Planet Cities are also championed by the consultancy Bioregional, which has worked with Brighton, the world's first declared one planet city, and is working with this year's European Green Capital, Bristol, to persuade it to make a similar declaration.

But Bioregional's methodology is also obscure and out of date. It does not publish its criteria and make them available for critique. Therefore it is not possible to verify the scale of the ecological footprint of a city or development and the extent to which it is being reduced.

A New Scientist piece written by Fred Pearce in 2013 criticized EF, remarking that it didn't take into account certain variables, which, if they were taken into account would make our ecological footprints even larger.

There have been a number of confidential reports circulated by WWF and Friends of the Earth debating the value of ecological footprinting.  While everyone agrees that ecological footprinting is a great concept for public relations, as it is an easy thing for the public to understand, the methodology is problematic and the data is difficult to keep up-to-date.

But if we do not use this methodology, what might we use?

The need for verifiability

Whatever it is, it must be verifiable and transparent. In a fast urbanising world with a growing population that is already living beyond the means of the planet this is an urgent task: to create, using open data, easily updatable info and present it in a way that people can actually use at all levels from government downwards to determine what is sustainable, i.e. what the planet can fairly provide.

In energy management, it is well known that "what gets measured gets saved". Energy management is a field that is well advanced in establishing baselines, monitoring and performance, with all sorts of software and technology geared to measurement and improving efficiency. There are international standards, the principal one being ISO 50001.

Our final set of metrics must be just as robust.

Carbon footprinting

Carbon footprinting might be one solution, or part of it. This has the advantage of being kept up-to-date on an annual basis, because national and international legislation supports it, but it does not capture other kind of impacts such as biodiversity loss or gain, pollution, etc.

Life Cycle Analysis

The real target of sustainable activity should be overall lifetime impact. This means that life-cycle analysis is another potential serious contender that could be deployed but again the data and the methodology is not quite up to what we actually need.

A Life Cycle Assessment (LCA) quantifies and assesses the emissions, resources consumed, and pressures on health and the environment attributed to different products over their entire life cycle. It quantifies all physical exchanges with the environment, whether these are inputs (resources, materials, land use and energy), or outputs (emissions to air, water and soil).

The advantage of using it is that life cycle assessment is already standardised through a range of ISO documents, including ISO 14040:2006 and ISO 14044:2006, which cover principles, framework requirements and guidelines and, published six years later, ISO/TR 14047:2012 and 14049:2012, which help with applying the earlier standards the impact assessment and inventory analysis.

The LCA process may be divided into four key steps:

  • identify goal and scope by defining boundaries and the functional unit
  • model the processes and resources involved in the system, collate the life cycle inventories of these processes and resources and generate any new inventory required
  • adjust life-cycle impacts in terms of mid points and endpoints
  • evaluate and interpret results and generate the report for decision-making.

Life cycle assessment is complicated enough for a single product. A building is an assembly of many different products, and a town or city may contain millions. Clearly this approach by itself from the bottom up will be impractical.

There is, however, an attempt ongoing to apply life-cycle analysis to land use.  The Joint Research Centre (JRC)'s Institute for Environment and Sustainability (IES) leads the European Platform on Life-Cycle Assessment.

WWF have sponsored this work in an effort to assess the impact of human activities on biodiversity, something which is also not captured by ecological footprint analysis and is therefore, in One Planet Development planning applications, treated separately. Applicants must demonstrate that they are improving the biodiversity of the land they occupy.

UNESCO Biospheres

UNESCO Biospheres are another attempt to find a sustainable way for human activities to live alongside nature, but they are a special case.  These undergo periodic reviews, but these are labour intensive, yet they do represent work in progress in terms of developing tools, testbeds for sustainable development on a wider scale.

Conclusion

The information pyramid for SEEAResearch for WWF conducted in 2010 found that many experts believe that it would be advantageous "to align the Ecological Footprint with the UN System of Environmental and Economic Accounting", and that it should be "part of a basket of indicators". Although one aggregated indicator is seen as essential for communication, it does not "provide enough detail to undertake a meaningful assessment of regenerative capacity compared with demand" (Wiedmann and Barrett, 2010).

The SEEA utilizes the principles of economic accounting, building on the existing System of National Accounts (SNA) to help reveal the relationship between the environment and well-being not revealed by GDP and national income.  See graphic, right.

It does not propose any single indicator or basket of indicators but is an approach to integrating statistics to allow for multiple purposes and multiple scales of analysis. However, there are several key aggregates and indicators that are directly derived from the accounting tables and are of interest to policy analysis

In a simlar way, as part of its work towards its Well-Being of Future Generatiosn Bill, The Welsh Government has placed ecological footprinting as one of five overarching indicators for Sustainable Development, under which more specific indicators can sit:
1.         Economic output – Gross Value Added
2.         Social Justice - percentage of the population in relative low-income households
3.         Biodiversity conservation – status of priority species and habitats
4.         Ecological footprint – national EF against the UK and global average
5.         Wellbeing - a standard set of 36 health questions which ask respondents about their own perception of their physical and mental health.

This seems to be a sensible approach. But WWF has argued that "Accounting for our actions in terms of carbon and footprint reduction, however statistically difficult, should be a pre-requisite of a nation aspiring to One Planet living", and therefore should be given more weight in this mix at an increasing level of detail.

Genuine Progress Indicator

An approach similar to this is undertaken by the Genuine Progress Indicator (GPI). Applicable to existing settlements, it uses 26 indicators: seven economic, nine environmental and ten social, combined into a single framework. From the costs of crime, pollution, commuting and inequality to the value of education, volunteer work, leisure time and infrastructure, the GPI helps us understand the true impacts of policies. But again, it is far from complete, particularly on the biodiversity side (no credits for improving it). In a sense it does complement the SEEA approach.

Realistically, since every area of land is different, every development would need to conduct a survey to establish a baseline from which biodiversity changes caused by the development could be measured. This is already part of the criteria for many planning applications.

BS 8904:2011 

The standard BS 8904:2011 might also be of interest in this context. It provides guidance for community sustainable development, a framework of recommendations and guidance to assist communities to improve their sustainability. But as far as I can make out it does not actually collect data on performance. Rather it is a community engagement tool.

Next steps

A recent piece of research which I received privately concluded:

"The EF has cemented its place as a pioneering and important step towards providing a framework and metric for measuring environmental limits.  We can expect to see it continue to be used. However, it will be increasingly important to understand what it can and can’t do, and how to make the most of it alongside the significant and growing generation of new tools now emerging." 

It is clear then that much more research needs to be done to develop a proper basket of indicators that is sufficiently mature, objective, transparent, open and verifiable to match the importance and effectiveness of carbon and energy accounting methodology.

I would love to hear of any work being done towards this end.

A follow-up to this post containing this feedback is here.

David Thorpe is the author of: