Ozone gas is a type
of oxygen. It filters the powerful radiation from the sun - the heat you feel and
light which makes the days. Without this shield of ozone, most life couldn't
exist on the surface of the planet. So humans are messing up something which
affects almost all plants and animals.
It was in my home, the Antarctic, where people first realised what was happening to the ozone. An enormous hole appears every spring, bigger each year. No one worried too much because few people (never mind us poor penguins!) live in that part of the world. Then the hole got so big it began to affect southern countries like Australia and New Zealand. People there now have to wear clothes and big hats on sunny days to stop the sun burning their skins and causing skin cancers. And now there's another big hole which opens up above northern Europe and North America every spring too. By 1996, the ozone had dropped to half what it should have been in the spring .
CFCs come in many different sorts. Not only do they destroy the protective ozone, they are also very strong greenhouse gases and so add to global warming. The richer countries have stopped making most of them. But even so, the levels of the two main types of CFC in the air remained the same during the1990s. They last a long time. Worse: others are rising. China has been building new factories to make CFCs and halons and now makes the most. It has a huge export market which includes illegal ('black market') sales to Western countries. All countries are supposed to get rid of these chemicals completely by 2010. But will that be in time?
more detail on ozone damage and the science behind it, click here.
 New Scientist, 15/5/99, 49;  New Scientist, 16/3/96, 7