APPLICABILITY OF ENVIRONMENTAL IMPACT ASSESSMENT INDICATORS ON THE USE OF NATURAL RESOURCES IN THE BUILT ENVIRONMENT

The paper addresses the outcomes of the analysis of state-of-the-art indicator-based approaches for the environmental impact assessment to quantify the impact of natural resources consumption. Life cycle based assessment methods are applied on the case of construction materials, construction products and entire buildings. The study has been conducted on behalf of the city of Zurich to support their strategy towards the 2000 Watt society with consideration of the potential trade-off situation between energy efficiency and renewable energies, greenhouse gas reduction potentials and the responsible use of (natural) resources. Some environmental impact assessment methods claim to consider natural resources in their framework combining energetic and natural resources, which are detected or reported partly as separate parameters. A few methods use natural material resources as an input parameter, whereas other approaches consider mass flows in relation to suspected reserves or the willingness of the market to pay a price for a resource or a product. An expert survey among the project advisory group members has shown that the recyclability of a material resource and the avoidance of dissipative losses should be reflected within a reliable resource-specific environmental impact assessment framework. To meet these requirements, the combination of different assessment methods to quantify the use of (natural) resources and their environmental impacts can be carried out without any further methodological development. The disadvantages are that the existing methods today do not meet all the requirements of a sustainable use of natural resources. Furthermore, the comprehensive results cannot be sensibly aggregated into a single number to support decision making processes.