Ecological footprint analysis applied to mobile phones

Ecological footprints (EF) have been used for more than 15 yr as an aggregate measure of sustainability of geographical regions, but also for certain products and activities. EF analysis measures the bioproductive areas required to produce resources such as crops and timber, the directly occupied areas for infrastructure, and areas for absorbing waste flows (mostly limited to carbon dioxide) in a given year for a defined population. The need to extend ecological footprint analysis to electronic products arose because so far, mobile phones have mainly been evaluated using life-cycle assessments with a focus on toxicity, end-of-life management, and energy use, thus ignoring the wider sustainability implications. This article presents the footprint results from three mobile phone case studies. To establish the land areas consumed by the mined materials used in electronic products, a database was developed based on literature data and on approximations from the density and overburden of materials. The relationship between abundance and overburden values was used in a regression analysis to estimate energy requirements in materials extraction where other data were not available. Using a life-cycle assessment approach, environmental burdens for producing and using a mobile phone were calculated and transformed into the instantaneous rate of resource consumption. Key results were that different electronic products have different ecological footprints and that the methodology proved sensitive enough to reveal differences in small electronic products and for monitoring technologies that use bioproductive space efficiently.