Temporal Considerations of Carbon Sequestration in LCA

Abstract

Accounting for carbon sequestration in LCA illustrates the limitations of a single global warming characterization factor. Typical cradle-to-grave LCA models all emissions from end-of-life processes and then characterizes these flows by IPCC GWP (100-yr) factors. A novel method estimates climate change impact by characterizing annual emissions with the IPCC GHG forcing functions (w/m2/yr), integrated over the same 100-year time horizon, and then relating the warming to the equivalent time-zero equivalent (TIZE) CO2 emissions. Net life cycle carbon sequestration for lumber using TIZE and GWP 100 were -464, -557, -669 and -416, -462, and - 552 kg CO2eq/m3 wood for a 25, 50, and 75 year service life, respectively. The spread between the two results is directly related to service life, with longer service lives exhibiting greater variation. The comparison exemplifies the need to harmonize carbon sequestration accounting methodology – particularly the temporal aspects.

Citation

Salazar, James; Bergman, Richard. 2013. Temporal Considerations of Carbon Sequestration in LCA. Salazar J, Bergman R. 2013. Temporal considerations of carbon sequestration in LCA. In: Proceedings from the LCA XIII International Conference, October 1-3, 2013, Orlando, FL 2013; pp.136-142.