ren wrote:
We haven't made a hole in the ozone layer. It's natural.
I dunno, I think the argument is that having certain man made chemicals in the atmosphere amplifies the ozone depletion of polar stratospheric clouds to levels far in advance of what would occur normally in nature - leading to possible broader implications to climate systems.
I'm only going on Wikipedia though, and here is some relevant points;
On 2 October 2011, a study was published in the journal Nature, which said that between December 2010 and March 2011 up to 80% of the ozone in the atmosphere at about 20 kilometres (12 mi) above the surface was destroyed. The level of ozone depletion was severe enough that scientists said it could be compared to the ozone hole that forms over Antarctica every winter. According to the study, "for the first time, sufficient loss occurred to reasonably be described as an Arctic ozone hole." The study analyzed data from the Aura and CALIPSO satellites, and determined that the larger-than-normal ozone loss was due to an unusually long period of cold weather in the Arctic, some 30 days more than typical, which allowed for more ozone-destroying chlorine compounds to be created
and
In the lower atmosphere, there is much more chlorine from CFCs and related haloalkanes than there is in HCl from salt spray, and in the stratosphere halocarbons are dominant. Only methyl chloride which is one of these halocarbons has a mainly natural source, and it is responsible for about 20 percent of the chlorine in the stratosphere; the remaining 80% comes from man made sources.