Assessing environmental benefits and economic costs of aviation environmental policy measures

Abstract

Despite the recent global economic downturn, longer term growth is anticipated for aviation with an increasing environmental impact, specifically in the areas of noise, air quality, and climate change. To ensure sustainable growth for aviation, decision-makers and stake-holders need to be armed with information on balancing environmental and economic interests. The main objective of this thesis is to address key shortcomings in current decision-making practices for aviation environmental policies. This work demonstrates how the inclusion of environmental impact assessment and quantification of modeling uncertainties can enable a more comprehensive evaluation of aviation environmental policy measures. A comparison is presented between the conventional cost-effectiveness analysis and an illustrative cost-benefit analysis focused on assessing a subset of the engine NO, emissions certification stringency options under consideration for the upcoming eighth meeting of the International Civil Aviation Organization's Committee on Aviation Environmental Protection. The Aviation environmental Portfolio Management Tool (APMT) is employed to conduct the aforementioned policy assessments. Monte Carlo methods are adopted to explicitly quantify uncertainties in the modeling process. To enable the aviation climate impact assessment required by the policy analysis, a separate component of this work focuses on advancing the climate impact modeling capabilities within APMT. Major contributions towards assessing aviation climate impacts in APMT include: improved characterization of uncertainty for NO1-related effects and for aviation climate damages, introduction of a reduced-order methodology for assessing climate impacts of methane emissions from the processing of alternative jet fuels, and comparison and validation of APMT results with external sources. This work also discusses the importance of uncertainty assessment for understanding the sensitivity of policy analysis outcomes to input and model parameter variability and identifying areas of future work. An uncertainty analysis for the APMT Climate Module is presented. Radiative forcing from short-lived effects, climate sensitivity, damage function, and discount rate are identified to be the model parameters with the greatest contribution to output variability for the Climate Module for any given aviation scenario. Key contributors to uncertainty in the difference between policy and baseline scenarios are determined by the nature of the policy. For the NO, stringency analysis, the NO. radiative forcing and associated efficacies are significant contributors to uncertainty in analysis outcomes. Information based on model uncertainty assessment is also used for distilling and communicating key analysis results to the relevant stake-holders and policy-makers through the development of the lens concept. The lens, defined as a combination of inputs and model parameters representing a particular perspective for conducting policy analysis, is applied in conducting the engine NO, stringency policy assessment.