Indicators of sustainable development allow cities to measure their progress against the sustainability targets they have set. These indicators should reflect the interconnectedness of issues across the three pillars of sustainable development, namely social, economic and ecological. Effective sustainability indicators move beyond measuring the triple bottom line towards an integrated measurement of the three pillars. To be useful sustainability indicators need to be relevant, easy to understand, statistically measurable, logically defensible, reliable and relevant.
The following selected examples of sustainability indicators illustrate the kind of information that will lead to an understanding of how a city is doing in terms of sustainable development:
Ecological footprint (this is based on a range of data on consumption and resource use within a geographic area - see text box). The obvious target is to achieve a footprint that indicates that the people in a city are living within the ecological limits of the globe.
Change in the number of homes built in an area that are thermally efficient with water saving devices (measures the quality of homes being built and thus leads to energy and water efficiency)
Change in greenhouse gas emissions as a ratio of GVA per capita (a reduction can indicate cleaner manufacturing processes or a reduction in use of fossil fuel motorized vehicles or electricity generated by coal)
Change in electricity use as a ratio of the number of users (while we need to bring more users into the system to promote equity, we need to promote energy efficiency or the use of renewable energy)
Change in waste recycling as a percentage of collected municipal waste
Change in the number of people using public transport, or the mode of public transport (this is a very good measure of the effectiveness and affordability of the public transport system provided by cities)
There are many other indicators and each city should develop its own measures of progress based on its vision and objectives.
Ecological foot printing
The ecological foot print is a resource management tool that measures how much land, water and atmosphere a human population requires to produce the resources it consumes and to absorb its waste with the existing technologies it has. A fair share of the earth resources was estimated by WWF to be 1.8 hectares per person of arable land in the world. The average South African footprint shows that every person is using 4.02 hectares per person which is more than double the earth's carrying capacity. In other words, if everyone on earth lived like the average South African we would need two earths to support those people.
Today humanity's total ecological footprint is 23% larger than what the planet can provide. When we measure the ecological footprint of a city we can estimate its overshoot and so devise strategies to reduce the footprint. In a country like South Africa it is important to do ecological footprints of different areas in order to determine the equitable distribution and use of resources and thus devise equitable strategies.
For instance a recent Cape Town study showed that the footprint of some of the wealthiest suburbs is 14 times what the earth can provide whereas the poorer suburbs had footprints that indicated that they were living within their fair share of the earth's resources.
Vacancies
South African Cities Network has the following post available: Manager - Programmes.
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