Review of methods for assessing the climate impacts of aviation technologies and the resulting best practices

Kurzfassung

The climate impact of aviation resulting from both CO2 emissions and non-CO2 effects is gaining attention from avia-tion stakeholders seeking to identify potential mitigation options. There is a need to consolidate the use of assessmentmethods and climate metrics, which are required to convert aviation non-CO2 effects into CO2-equivalent emissions. Weprovide an overview of the operational, technological and scenario-based climate impact assessment methods that havebeen applied in literature as well as considerations and requirements for the choice of climate metric. We propose a four-layer technology climate impact assessment methodology, which includes: (1) the technology parameters, such as entryinto service and temporal and spatial network use; (2) the calculation of three-dimensional aircraft trajectories and emis-sion inventories; (3) the calculation of radiative forcing and induced temperature change time series; and (4) the overallclimate impact, measured using a climate metric. We recommend two climate metrics that best fulfill the requirements,the Average Temperature Response (ATR100) and the Efficacy-weighted Global Warming Potential (EGWP100), bothover 100 years. Additionally, we discuss further steps, such as the understanding of the most sensitive parameters in thisapproach, how uncertainties can be included to provide robust estimates, aspects of verification and update possibilitiesfor new findings in research.