A framework for assessing desertification environmental impact in LCA

NÚÑEZ, M; CIVIT, B; MUÑOZ, P; ARENA, AP; RIERADEVALL, J; ANTÓN, MA

Chile

Conferencia; III Conferencia Internacional de ACV en Latinoamérica; 2009

CIMM - UNEP SETAC Life Cycle Initiative

Land use human intensive activities cause important and many times irreversible shifts in land, namely biodiversity loss, desiccation, changes in groundwater availability, increased pollution of soils, soil erosion and soil degradation. For that reason, land use is included as an impact category within LCA studies. However, there is no scientific agreement on the life cycle assessment methods for land use related impacts, which determines either the exclusion or the lack of enough assessment of these local environmental impacts. Therefore, adjustments to the LCA methodology that take the aforementioned impacts into account are a subject of study. Soil irreversible degradation in arid, semi-arid and dry sub-humid areas, i.e. desertification, is one of the main problems affecting sustainability of these regions, especially in developing countries (United Nations, 1994). According to UNEP (2006), 41% of the terrestrial ecosystems are drylands, where lives one-third of the world’s population. Between 10% and 20% of these areas are degraded or unproductive. Worldwide, the highest desertification risk is found in Africa, some Arabian countries, Australia, the western edge of South America and several Mediterranean countries. In spite of this environmental, social and economic problem, to date there has been no attempt to include the impact of desertification in LCA studies. Thus, it is of great importance to include desertification impact in LCA of any human intensive activity developed in high desertification risk areas.  This work aims to develop a methodology for including the desertification environmental impact derived from land use in LCA studies. For the LCI phase, four environmental biophysical indicators belonging to the state and pressure framework were selected, namely aridity index, erosion, aquifer exploitation and fire risk. Social and economic indicators were not taken into account due to the disagreement related to them. The values of each one of the four indicators into the LCI step were determined according to a created scale of values.                The characterisation factors (CFs) were established for the four indicators estimated in the LCI for the large natural areas of the world using the Bailey’s ecoregions classification (Bailey, 2002) by means of geographical information systems (GIS). In this way, soil quality has been bore in mind in the land use assessment.    The LCIA scheme proposed requires data on occupied land area and lasting time of the activity under analysis, apart from the LCI and CF values. The developed methodology allows for the calculation of the desertification impact of any type of human activity (agriculture, industry, mining, among others), as well as the identification of the scenarios without desertification impact. The assessment scheme proposed may be complemented with specific indicators for each kind of human activity (salinity for agricultural activities, soil crusting for building activities, etc). GIS technologies have facilitated the achievement of the aims of this study. Therefore, the development of life cycle impact assessment models related to land use can be enhanced by considering the use of GIS. The simultaneous application of both techniques offers great advantages to gather useful information that can be applied to decision-making in land management.