Current Lifecycle Analysis Methods are Inadequate for Evaluating Climate Mitigation Options.

Lifecycle analysis (LCA) metrics of greenhouse gas emissions savings are increasingly being used to inform the selection of technologies to be supported by climate policies.  Our concern is that current widely-accepted LCA methods are designed to provide technology specific estimate of lifecycle emissions on a per-unit basis, not to measure the impact of a policy induced change in a technology on emissions in all affected sectors.  We propose a novel policy-based method for calculating lifecycle emissions savings, and demonstrate its superiority relative to current LCA methods in the context of US biofuel policies.  Current LCA methods routinely generate inaccurate estimates of the predicted impact of corn ethanol policies on emissions.  In three of the four policy cases we consider, current LCA methods drastically overestimate emissions savings, estimating emissions savings of nearly the same magnitude as the emissions increases induced by the policy.  In the remaining policy case, current LCA methods underestimate emissions savings relative to the policy-based method.