Apply WARM emissions factors against waste generation date to estimate of the lifecycle GHG impacts of generated materials; include these in the inventory.
- Description of tool/’patch’ (action statement): Use waste composition study and waste flow/disposal records to estimate the quantities of individual materials disposed of. Use recovery survey data to estimate the quantities of individual materials recovered. Add disposal and recovery to estimate waste generation (by material). Multiply the generation tonnage of individual materials by materials-specific "life cycle" emissions factors (from WARM or other sources) to account for the GHG impacts of producing and disposing of materials. Include these in the inventory so that future reductions in disposal count as reductions in inventoried emissions.
- Tips/best practices for applying the tool: TBD.
- Issues/obstacles: "Life cycle" emissions are not available in WARM for many key materials, including food and many construction materials. Also, may need more thought as to which life cycle emissions to include. One concern is whether or not to include forest carbon sequestration factors. EPA's WARM model includes estimates of carbon sequestered as a result of changes in land use when wood-based materials are source reduced or recycled. These estimates are based on analyses of marginal changes in land use practices, which is different from the emissions factors associated with energy savings (which are based on average conditions).
- Resources/citations (justification for use of this particular tool/patch): Oregon used this approach in 2004 not in an official inventory but rather to build an estimate of the baseline "life cycle" emissions of materials generated. The baseline was needed to compare against "life cycle" emissions of waste generation under a variety of policy and program options evaluated for inclusion in the State's GHG Reduction Strategy. For example, to estimate the GHG reductions resulting from increasing salvage of reusable building materials, we ran the model twice: once estimating life cycle emissions for one profile of waste generation (with more building materials purchased and disposed) and once estimating life cycle emissions for a smaller profile of waste generation (with fewer building materials purchased and disposed). The difference between the two model runs was then taken to be the GHG reductions associated with increasing reuse of building materials. See pages 99 - 105 of the Oregon Strategy for Greenhouse Gas Reductions for details regarding this modeling activity. Technically, this was not an inventory approach, although it might be applied to an inventory.