Are recent Arctic ozone losses caused by increasing greenhouse gases?

It has been suggested that the Arctic ozone losses observed in recent years might be a manifestation of climate change due to increasing greenhouse gases. We here offer evidence to the contrary, by focusing on the volume of polar stratospheric clouds (V-PSC), a convenient proxy for polar ozone loss whose simplicity allows for easily reproducible results. First, we analyze the time series of V-PSC in three reanalysis data sets and find no statistically significant trends in V-PSC-nor changes in their probability density functions-over the period 1979-2011. Second, we analyze V-PSC in a stratosphere-resolving chemistry-climate model forced uniquely with increasing greenhouse gases following the A1B scenario: here too, we find no significant changes in V-PSC over the entire 21st century. Taken together, these results strongly suggest that the sporadic high ozone losses in recent years have not been caused by increasing greenhouse gases.