April 12, 2023
Journal Article
An inconsistency in aviation emissions between CMIP5 and CMIP6 and the implication on short-lived species and their radiative forcing
Abstract
We report on an inconsistency in the latitudinal distribution of aviation emissions between the data products of phases 5 and 6 of the Coupled Model Intercomparison Project (CMIP). Emissions in the CMIP6 data occur at higher latitudes than in the CMIP5 data for all scenarios, years, and emitted species. A comparative simulation with the chemistry-climate model EMAC reveals that the difference in nitrogen oxides emission distribution leads to reduced overall ozone changes due to aviation in the CMIP6 scenarios, because in those scenarios the distribution of emissions is partly shifted towards the chemically less active higher latitudes. The radiative forcing associated with aviation ozone is 7.6% higher for the year 2015 when using the CMIP5 latitudinal distribution of emissions compared to when using the CMIP6 distribution. We do not find a statistically significant difference in the radiative forcing associated with aviation aerosol emissions.Published: April 12, 2023