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the largest potential indicator of environmental impact. The fossil fuel depletion score is one order of magnitude (~10 ) greater than the next signi fi cant indicators, human health effects of climate change, agricultural land occupation, and human health effects of particulate matter formation, which in turn are an order of magnitude greater than the remaining indicator scores. Although use of normalization factors adds additional uncertainty to results (Van Hoof et al., 2013; Benini and Sala, 2015; Weidema, 2015), the profound differences increase the likelihood that these are the impact categories with relatively higher contributions to average per person global impacts. It should also be noted that the differ- ences between indicators are more substantial than the differences between Albany and Box Elder in the context of a global average consumer. Fig. 4 is a comparison of results for the most signi fi cant impact categories for the production of Bounty at Albany and Box Elder based on the endpoint normalization, along with water consump- tion. The impact scores are internally normalized to re fl ect 100%of the highest score. Water consumption is an additional indicator not available for normalizing to annual world emissions, but is relevant for products that are made with pulp, as their processing requires
In the climate change category for both TRACI and RECIPE methods, CO 2 uptake was assigned a CO 2 -eq. value and 1 and biogenic CO 2 emissions were assigned a CO 2 -eq of 1 so that both biogenic uptake and emissions were characterized to be consistent with the adjustments to the life cycle inventory. This results in the calculation of net global warming potential which can be repre- sented in the following equation: GWP net ¼ GWP gross þ GWP uptake (2) where GWP gross is the global warming potential of all greenhouse gas emissions regardless of fossil or biogenic origin, and GWP uptake is the global warming potential of plant uptake, which is always a negative value.
3. Results
Fig. 3 shows results of the LCA for 1 roll of paper towels made at Albany and Box Elder as a fraction of average global person con- sumption estimates using the ReCiPe endpoint normalization values. Fossil fuel depletion across the full paper towel life cycle is
Fig. 3. Normalized results of producing 1 roll of Bounty ® paper towels at Albany and Box Elder.
Fig. 4. Comparison of results for selected indicators calculated for the production of Bounty ® at Albany and Box Elder. The impact scores are internally normalized to re fl ect 100%of the highest score.
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