Wiedmann and Minx (2007) describe two methods to calculate the carbon footprint using LCA: process analysis
(PA) and Environmental Input-Output Analysis (EIO). The process analysis is a bottom-up approach to analyze a
product from creation to the end of its life, taking into account direct and some secondary emissions, but having the
disadvantage of double counting. EIO involves a top-down approach and is applied on sectoral level, expanding
boundaries and eliminating the problem of double counting. The authors recommend the application of a hybrid
model, combining advantages of the two methods: using EIO as primary method, and locally applying the PA.
The analyzed emissions within such a model are divided into three levels, depending on the control power of the
organization/community on their sources:
scope 1: direct emissions, for activities directly controlled by the organization/ community;
scope 2: indirect emissions, derived from the use of electricity, heat and cooling;
scope 3: other indirect emissions, from downstream and upstream (along the supply and retail chain)