Footprinting
UK Households- How big is your ecological garden?
Craig Simmons and Nicky Chambers, Best Foot Forward
Limited.
The Future Centre, Oxford OX4 1RQ.
Tel: 01865 250818
Fax: 01865 794586
Web: www.bestfootforward.com Email: mail@bestfootforward.com
When historian Fernand Braudel wrote Le Méditerranée in 1949, a chronicle of the Mediterranean in the late 16th century, he was unwittingly making history himself as one of Europe’s earliest ecological footprinters.
However, his use of land areas to monitor the trade, consumption and production patterns of agricultural products was not borne out of environmental concern. Rather, he shrewdly realised that the hectare was a far more reliable comparative indicator of economic activity across the diverse Mediterranean basin than the ducat, whose exchange rate and net worth varied wildly.
Some modern ecological economists are attracted to the hectare for very much the same reason; it provides a stable ‘currency’ suitable for tracking environmental impacts. It also sheds considerable light on the measurement of sustainability. Most accepted definitions of sustainability include the concept of living off nature’s ‘interest’ rather than its ‘capital’. Land productivity is an excellent indicator of the locally, regionally or globally available natural ‘interest’.
The use of land area as an aggregate indicator also has a certain resonance amongst environmentalists, both professional and amateur, which makes its use doubly attractive. This can be expressed in many ways. William Rees, responsible for bringing ecological footprinting into the modern world, has referred to the footprint of an urban region as a ‘solar collector… the photosynthetic surface required to recharge the city’s ecological batteries’ (Rees 1997). Bill McKibben has described personal footprints rather more prosaically as ‘the balloons above our heads, our hungry shadow selves’ (McKibben 1998). This richness of imagery associated with the use of ecological footprinting is an asset that should not be underestimated. One of the main hurdles to implementing effective environmental change programmes is communicating the concepts of sustainability and ecological damage. After all, who is able to visualise a tonne of carbon dioxide and understand its significance?
Wackernagel and Rees (1995) graphically demonstrated how ecological footprinting could be employed to express a wide range of environmental impacts. Moving beyond the farmed products handled by Braudel, they showed how the method could be used to measure the use of forest products, energy consumption and the built environment. Largely parallel developments by the authors, based on initial data collected by CAG Consultants, have further added measurement of waste impacts and water consumption.
The results of our work are a series of interacting mathematical algorithms capable of converting resource use to a land-area equivalent. Depending on the granularity of the calculations, different sets of algorithms can be used to measure the ecological footprint of anything from an individual object or activity to the whole planet.
The ease and flexibility with which ecological footprinting can be applied to express impacts at a local, regional or global level is clearly a strength. Footprinting has been used to explore the sustainability of individual planning applications (Langford 1998), the impact of individual establishments (Lewis 1998; Paulson 1998), international trade (IIED 1995), as well as the ecological ‘hinterland’ of cities and larger regions (for example see Wackernagel 1998, Girardet 1997). For example, the authors recently converted National footprint data supplied by Wackernagel to estimate the ecological footprint of a selection of UK Cities (see Figure 1).
EcoCal - An ecological footprinting tool for households
In 1995 the authors felt that ecological footprinting, although clearly still an emerging methodology, had matured sufficiently to form the basis of a household environmental impact ‘calculator’. With a working title of the Green Household Index, the idea finally saw light as a fully functioning product in 1997. Called ‘EcoCal’, the development was largely funded by Going for Green[1] and, latterly, the Environment Agency.
EcoCal is first and foremost an easy-to-use computer-based questionnaire which combines a footprint-based measurement scheme with a package of facts, hints, tips and contact details aimed at bringing about more environmentally-responsible behaviours (see Figure 2). It is designed to be used unassisted by the general public. For those without access to a computer, EcoCal is also produced in a paper-based format.
What EcoCal does is measure a household’s ‘ecological garden’ - the amount of land required to support the lifestyles of the occupiers.
For practical reasons, the questionnaire comprised just 45 questions. These were organised into six categories of household impact; transport, energy, water, waste, house & garden and purchasing. Table 1 provides an overview of the information gathered within each topic.
Such a short questionnaire cannot hope to measure all impacts. Questions were therefore determined on the basis of availability of data, significance of the impact, and the ability of households to ‘make a difference’ by acting to reduce their score.
Data
Collection
During the Summer of 1997 Going for Green put EcoCal through rigorous market testing programme which provided the authors with the opportunity to collect data on the ecological footprints of UK households; to our knowledge the first such exercise. The authors were eager to determine both how impacts were distributed across different activities and to explore those aspects of household lifestyles which had the most significant effect.
Data from 42 households (90 adults and about 40 children) was felt reliable enough to be included in our final analysis. This was collected from 6 geographical regions within the United Kingdom, chosen to represent a range of socio-economic factors. Household size varied from 1 to 5 adults (aged over 16).
Households were largely self-selecting although a financial incentive was provided to entice the widest cross-section of the public.
Results
The average household ecological footprint was found to be almost exactly 5 hectares (or 50,000 square metres) or 1.7 hectares per occupant (including children). Assuming a typical semi-detached house in the UK occupies a 100m2plot of land, its ecological garden would then occupy the land taken up by 500 of its neighbours.
The range of footprint values was surprisingly large; from less than half a hectare per household to several hundred. The high values were typically the result of large families with energy inefficient homes taking one, or more, long-haul holidays abroad coupled with one-off ‘high impact’ purchases (such as hardwood furniture). Arguably such acquisitions should be amortised over a longer period of time.
Chart 1 shows the comparative footprints of the different categories measured by EcoCal. Transport ranks as the highest impact (1.52 hectares) closely followed by direct energy use (0.99 hectares). General purchases and the impacts relating to the house and garden both rated at about 0.5 hectares with waste and water scoring the lowest.
The latter two categories are perhaps artificially low. Recent improvements to the methodology now treat waste and water more completely with the result that the footprint values are slightly higher.
The ecological footprint figure of 5 hectares per household (or 1.7 hectares per person) derived from the EcoCal algorithms, a bottom-up analysis, is entirely consistent with the only other known UK per capita estimates of 5.2 hectares (Wackernagel et al 1997) and 3.7 hectares (the authors’ own work in progress). Both of these are based on top-down analyses although they use different data sources, slightly different methodologies, and the latter currently excludes certain categories of imported products.
It should be noted that both of the top-down estimates apportion to individuals a substantial range of industrial and public sector consumption outside the scope of the EcoCal questions. This is a plausible reason for the discrepancy between the EcoCal and the National estimates. It should also be remembered that some of the data collated at a National level is itself approximated as no reliable, official figures yet exist.
It therefore seems likely that EcoCal is capturing many of the large and significant environmental consequences of household actions. The most obvious shortfall is in the area of purchasing where the practical limits on questionnaire size dictated that the topic was restricted to just 9 questions. Inevitably, this lead to simplifications and omissions. For example, the consumption of takeaway and restaurant food was treated rather generously whilst the use of household products was excluded altogether.
Wackernagel and Rees have estimated a sustainable and equitable level of consumption, ones ‘earth share’ or ‘personal planetoid’, to be about 2 hectare (Wackernagel & Rees 1995; Rees 1997; Wackernagel et al 1997;). What would constitute a sustainable level of household consumption, in terms of the impacts measured by EcoCal, is difficult to define without further research. Assuming EcoCal does capture roughly one third of an individuals National per capita footprint then this would suggest that an average sustainable ecological garden is approximately 40% the size of that found in our study (around 2 hectares or two-thirds of a hectare per occupant).
The good news is that a few households are already meeting this target suggesting that there is ample scope for improvement in the environmental performance of the higher impact households.
Guided by our findings, any public campaign to minimise individual environmental impact would probably wish to focus its resources firstly on household transport choices, then energy use. Even with the limited information on shopping habits, it seems that education about specific purchasing decisions would also yield benefits. Of course, consumption data may vary from region to region, necessitating different priorities.
Ecological footprinting has proven itself to the authors to be a useful indicator for exploring relative and aggregated environmental impacts. Allying the methodology to a computer-based delivery system has also allowed a level of interactivity not previously possible. The combination opens up exciting possibilities for future developments.
Work on refining the algorithms for household measurement is on-going as is the expansion of EcoCal to cater for different user needs. Several corporations are already using a network version of EcoCal as part of their employee involvement programmes. Requests have also been received for footprinting tools that look at particular aspects of lifestyle, transport or energy use for example, in more detail.
The authors, with the support of Going for Green, are currently looking for partners to convert EcoCal for use outside of the UK.
Footprinting tools for other audiences have also been considered and a prototype regional calculator, called StepWise, for planners, non-governmental organisations and policy-makers, has already been produced (see Figure 3).
Other application ideas are still in their infancy; such as a tool for product designers to allow them to assess the environmental rating of various design alternatives.
Footprinting has come a long way since
Braudel and still has some way further to go. Yet his words seem strangely
prophetic even now: ‘Land continued to be
the most coveted possession…the investor could always see with his own eyes how
his money was bearing fruit on vine or in the farmhouse. Such security was
worth a great deal.’
Braudel, F. (1992) The Mediterranean and the Mediterranean World in the Age of Philip II (abridged English edition) HarperCollins, London. Originally published 1949 in French as Le Méditerranée et le Monde Méditerranéen à l’Époque de Philippe II.
Langford, A. (1998) Director, Permaculture Academy of Britain, Personal Communication.
Paulson, K. Unpublished report for local Environment Forum which calculates ecological footprint of Oxford Brookes University, Oxford, UK.
Lewis, K Ecological Footprint Analysis – An ‘average’ method for an ‘average’ world. Unpublished PhD Thesis, which calculates ecological footprint of various regions and establishments with East Anglia.
McKibben, W. (1998) A Special Moment in History, in: The Atlantic Monthly, 281 (5), pp. 55-78.
IIED (1995) Citizen Action to Lighten Britain’s Ecological Footprint, report prepared by the International Institute for Environment and Development for the UK Department of the Environment (London, International Institute for Environment and Development).
Wackernagel, M. and Rees, W. E. (1995) Our Ecological Footprint: reducing human impact on the Earth (Gabriola Island, BC, New Society Publishers).
Rees, W. E. (1997) Is Sustainable City an Oxymoron?, Local Environment 2(3), pp. 303-310.
Wackernagel, M. (1998) The Ecological Footprint of Santiago de Chile, Local Environment 3(1).
Girardet, H. (1997) Cities as Superorganisms http://oneworld.org/guides/thecity/index.html.
Mathis Wackernagel, Larry Onisto, Alejandro Callejas Linares, Ina Susana López Falfán, Jesus Méndez García, Ana Isabel Suárez Guerrero, Ma. Guadalupe Suárez Guerrero (1997) Ecological Footprints of Nations; How Much Nature Do They Use? -- How Much Nature Do They Have?, (December 1997 update) Earth Council http://www.ecouncil.ac.cr/rio/focus/report/english/footprint/
[1] Going for Green is Britain’s biggest environmental awareness campaign. It is funded by both the Department of the Environment and the public sector. It promotes the Green Code, five point guide to small, individual actions which every household can take to help reduce damage to our environment.