Future Arctic temperature and ozone: The role of stratospheric composition changes

Abstract

Abstract Using multidecadal simulations with the European Centre/Hamburg–Modular Earth Submodel System Atmospheric Chemistry (EMAC) model, the role of changing concentrations of ozone‐depleting substances (ODSs) and greenhouse gases (GHGs) on Arctic springtime ozone was examined. The focus is on potential changes in the meteorological conditions relevant for Arctic ozone depletion. It is found that with rising GHG levels the lower Arctic stratosphere will cool significantly in early winter, while no significant temperature signal is identified later in winter or spring. A seasonal shift of the lowest polar minimum temperatures from late to early winter in the second part of the 21st century occurs. However, Arctic lower stratosphere temperatures do not seem to decline to new record minima. The future Arctic lower stratosphere vortex will have a longer lifetime, as a result of an earlier formation in autumn. No extended vortex persistence is found in spring due to enhanced dynamical warming by tropospheric wave forcing. Because of the dominant early winter cooling, largest accumulated polar stratospheric cloud (PSC) areas ( A PSC ) are projected for the middle of the 21st century. A further increase of A PSC toward the end of the 21st century is prevented by increased dynamical polar warming. EMAC suggests that in the near future, there is a chance of low Arctic springtime ozone in individual years; however, there is no indication of a formation of regular Arctic ozone holes. Toward the end of the 21st century, when ODSs will be close to the 1960 levels, further rising GHG levels will cause increased Arctic springtime ozone.