Comparing two life cycle assessment approaches: a process model vs. economic input-output-based assessment

We compare two tools for Life Cycle Assessment (LCA). The software GaBi (Ganzheitliche Bilanzierung Integrated Assessment) from Germany is based on a process model approach, as recommended by the Society of Environmental Toxicology and Chemistry (SETAC). These results are contrasted to those from the method developed by Carnegie Mellon University's Green Design Initiative, Economic Input-Output Life Cycle Analysis (EIO-LCA). The EIO-LCA model uses economic input-output matrices, and industry sector level environmental and nonrenewable resource consumption data to assesses the economy-wide environmental impacts of products and processes. The results from the alternative approaches are compared in terms of toxic chemical releases, conventional pollutant emissions, energy use by fuel type, and use of ores. We find that most of the values from the two tools are within the same order of magnitude, despite the fundamental differences in the models. We contrast the two approaches to identify their relative strengths and weaknesses.