(790f) Accounting for Ecosystem Services in Life Cycle Assessment by Eco-LCA: Advances in Methodology and Software

Ecologically-Based Life Cycle Assessment (Eco-LCA) is a framework to account for the role of ecosystem goods and services in supporting economic activities (Zhang et al., 2010). Ecosystem services are contributions from nature without which sustainability of any activity on earth would not be possible. They include provisioning services like food, biomass and water; regulating services like regulation of floods, climate and pests; supporting services like biogeochemical cycles and photosynthesis; and cultural services like tourism, aesthetics and spiritual development. Despite their importance, most sustainability methods have not accounted for their role.

In our previous research, we have developed ways of accounting for many ecosystem services, and have developed an environmentally extended input-output (EEIO) model of the United States economy to permit a quick Eco-LCA of economic sectors (Zhang et al., 2010). Hybrid Eco-LCA models have also been developed by combining detailed process level data with the IO model. Thermodynamic methods based on exergy and emergy analysis are used to aggregate various ecosystem services (Baral et al., 2012).

This presentation will describe some significant recent developments in the Eco-LCA data, method and software. A large number of provisioning services are now quantified in Eco-LCA as intermediate flows from relevant sectors by using the algebra of EEIO models. This relies on physical data about products such as grains, legumes, fish, biomass and medicinal plants. The Phosphorous cycle is also included in Eco-LCA by incorporating its flows into relevant sectors. This adds to the C and N cycles that are already included in Eco-LCA. Many ecosystem services, especially regulating services, are difficult to quantify. This challenge is overcome in this work by means of a novel approach of qualitative EEIO modeling and LCA. This approach relies on gathering information about the extent to which each sector of the economy depends on the selected ecosystem service. This dependence is represented in qualitative terms as “high,” “medium,” and “low,” and this information is propagated through the IO model to get qualitative information about the extent to which the selected economic product depends on the ecosystem service.

These new developments have been implemented in the Eco-LCA software available at http://resilience.osu.edu/ecolca/. The software permits three types of analyses: thermodynamic, ecosystem services, and footprints. Thermodynamic analysis includes cumulative exergy consumption analysis with and without ecosystems. This analysis with ecosystems becomes analogous to emergy analysis. The tool enables calculation of metrics such as renewability index and thermodynamic return on investment. Analysis of ecosystem services provides information about these services by following classification systems like the one described in the first paragraph. These data are represented in multiple units, but may be aggregated by a hierarchical scheme that relies on thermodynamic methods. Footprint methods include univariate indicators like carbon, nitrogen, land use and water footprints. Use of this software for performing tiered hybrid LCA by combining process level data with the economy scale EEIO model will also be described and demonstrated, if time permits.

References

Baral, A., B. R. Bakshi, R. Smith, Assessing Resource Intensity and Renewability of Cellulosic Ethanol Technologies using Eco-LCA, Environmental Science and Technology, 46, 4, 2436–2444, 2012

Zhang, Y., A. Baral, B. R. Bakshi, Accounting for Ecosystem Services in Life Cycle Assessment, Part II: Toward an Ecologically-Based LCA, Environmental Science and Technology, 44, 7, 2624-2631, 2010