TABLE OF CONTENTS - The Professional Green Building Council

Theme B: Creating a livable, healthy and environmentally viable citiesPressures exerted on the environment by human settlements can be evaluated bythe sustainable index of the “ecological footprint” [2], which translates the amountof resources swallowed up by cities and the amount of wastes they produce intoareas of productive land. This measurable index thus represents the total amount ofdifferent areas scattered all over the world on which each city depends and whichlargely exceed its physical boundaries.Nowadays, as a result of present harmful patterns of production and consumption,the ecological footprints of existing cities already cover almost the total area of theearth, and are tending to increase day by day, while arable soils, forests and naturalareas continuously decrease. In addition to this land use issue, the ecologicalimpacts of current cities exceed by 30% the carrying capacity of the earth asregards renewal of resources and assimilation of wastes.An important point concerning cities is the fact that the ecological footprint(corresponding to the ecological territory necessary to sustain the city) exceeds bya factor between 100 and 1000 their physical territories. That means that throughthe local control of the physical structure of the city, urban planners control onlyless than 1% of the ecological territory of the city, which is scattered around thewhole planet and is mostly unregulated.This fact can be seen in the percentages of direct and indirect energies of someAsian cities (Fig.1) and is particularly critical in the case of Hong Kong as will beexplained below.414