VATIS UPDATE Article

In a study, a team of researchers from Japan Agency for Marine-Earth Science and Technology, Japan, have focused on the response of the climate to the temporal evolution of the ozone hole. In this analysis they employed the Earth System Model for Interdisciplinary Research on Climate with interactive chemistry (MIROC-ESM-CHEM) comprehensive of a coupled atmosphere-ocean general circulation model as well as sea ice, marine ecosystem and land ecosystem components.

Because of the prohibitive computational cost of the interactive chemistry, only few previous experiments adopted a similar complex configuration to investigate this topic, while the majority of them included the ozone hole climatology in the atmospheric component. Nevertheless, the standard configuration causes the dynamics of the model evolving without being coupled with the ozone chemistry feedback and this potentially prevents a correct evaluation of the feedbacks.

Two ensembles covering the period 1960-2050 were examined: the first ensemble includes all forcings as prescribed in the standard historical Coupled Model Intercomparison Project Phase 5 simulations while the other ensemble is analogous but with ozone depleting substances (ODS) held fixed at 1960 levels. Here the researchers showed their difference that represents the response of the climate to ozone forcing.

According to previous studies, the results point to a driving influence of the ozone hole on the climate of the Southern Hemisphere with an evident impact on all the components of the climate system in summer during the historical period (i.e. 1960-2005) and an overall effect counteracting the greenhouse gas forcing during the future decades (i.e. 2006-2050) under the RCP 4.5 scenario.