The Antarctic Ozone Hole reached its largest extent for this year on September 11, according to data from both NASA and NOAA (the US National Oceanic and Atmospheric Agency) at 9,300,00 square miles only slightly larger than last year’s peak. The largest hole size was recorded in 2000 on September 9 and is part of a general decrease in the hole since then.
The size of the hole was slightly bigger than the land surface of North America.
Ozone is a variety of oxygen that cannot be used for respiration by any known living creature, and is in fact lethal in a high enough doze. However it is good at blocking out the heat of the Sun. Without the ozone layer the Earth would be too hot to live on. It also shields against ultraviolet light, which in a too high dosage kills plants.
The Montreal Protocol was signed by the world’s nations in 1987 in response to the discovery of the hole and of the cause of the hole mainly chlorine-containing chlorofluorocarbons (CFCs) and bromine-containing halons, all produced during industrial activity. Both CFCs and halons were very useful substances, in insulating fridges and putting out fires, and alternative have been used as much as possible since. This is one clear way in showing that current global warming has been manmade.
So, surely a shrinking Antarctic Ozone Hole is good thing. Well, perhaps. It rather depends on the cause. If this is due to the Montreal Protocol reducing CFC and halon use, then yes, it is.
But, then again it could be due to the effects of global warming from other sources or even local warming of Antarctica.