es3050949_si_003.xls (54.5 kB)
Two-Step Sensitivity Testing of Parametrized and Regionalized Life Cycle Assessments: Methodology and Case Study
dataset
posted on 2013-06-04, 00:00 authored by Christopher L. Mutel, Laura de Baan, Stefanie HellwegComprehensive sensitivity analysis
is a significant tool to interpret
and improve life cycle assessment (LCA) models, but is rarely performed.
Sensitivity analysis will increase in importance as inventory databases
become regionalized, increasing the number of system parameters, and
parametrized, adding complexity through variables and nonlinear formulas.
We propose and implement a new two-step approach to sensitivity analysis.
First, we identify parameters with high global sensitivities for further
examination and analysis with a screening step, the method of elementary
effects. Second, the more computationally intensive contribution to
variance test is used to quantify the relative importance of these
parameters. The two-step sensitivity test is illustrated on a regionalized,
nonlinear case study of the biodiversity impacts from land use of
cocoa production, including a worldwide cocoa products trade model.
Our simplified trade model can be used for transformable commodities
where one is assessing market shares that vary over time. In the case
study, the highly uncertain characterization factors for the Ivory
Coast and Ghana contributed more than 50% of variance for almost all
countries and years examined. The two-step sensitivity test allows
for the interpretation, understanding, and improvement of large, complex,
and nonlinear LCA systems.