The chlorofluorocarbons (CCl2F2, CCl3F, etc.) are not only GHG contributors but also the suppliers of atomic chlorine to the upper atmosphere, causing the loss of stratospheric ozone. Every September since the mid-1980s a rapid loss of ozone occurs in a few weeks over the south polar area, resulting in the formation of the well-known Antarctic Ozone Hole, which fades away in mid-spring (November). These losses in stratospheric ozone led in 1987 to the international adoption of the Montreal Protocol which banned the further manufacture and release of the chorofluorocarbon gases. This Protocol has now been in effect for 22 years, and has been very successful. Nevertheless, the Antarctic ozone loss will occur throughout the 21st century because of the long survival lifetimes of the CFCs which have already been released.
Feedback processes involving reductions in reflectance (albedo) from ice to water, or from to snow to rock cause enhanced warming in the polar north, and the climate is changing rapidly in the Arctic with substantial biological effects.