Appreciate your concession there. To be clear, I'm not saying that ozone holes could never be natural according to current knowledge -- indeed, a big enough volcanic eruption would be expected to create one. I'd imagine a big oceanic asteriod impact would inject a lot of chlorine to the upper atmosphere as well.
For CFCs to not be the culprit, you'd need to show not only that naturally ocurring holes have ocurred in the past, but that they ocurr due to natural cycles not connected to triggers like big eruptions or impacts, since we can be pretty confident no such trigger has happened in the last 50 -100 years. Just because volcanoes can cause holes doesn't mean that fluorcarbons don't also cause holes. If someone found that ozone depletion happens on a routine cycle for reasons of atmospheric dynamics, that'd cause some doubt.
Space/Science » in reply to Got any evidence? Any at all?
Natural ozone holes