Stephen Leahy*
TORONTO, Sep 20 (Tierramérica) – Another giant ozone hole has opened up over the Antarctic, while evidence mounts that 20 years of international efforts have finally helped the atmosphere to start to heal itself.
The “hole” over the South Pole — actually an annual thinning of the ozone layer, which protects Earth from the sun’s ultraviolet radiation — measured about 24 million square kilometres, nearly the size of North America, according to the Sep. 8 estimate by the renowned British Antarctic Survey, a scientific organisation that has been studying the region for the past six decades.
The ozone hole will continue to grow and likely be one of the larger and “deeper” ones, perhaps 28 million square kilometres, predicts Andrew Klekociuk of the Australian government’s Antarctic Division. The largest ever recorded was 30.3 million sq km in 2000, according to NASA, the U.S. space agency.
Stephen Leahy, International Environmental Journalist 
How long have we been able to detect the hole in the ozone layer? Perhaps the sizes we are seeing are not unusual in earth’s history.
Ozone depletion first detected in late 1970s, started to see hole form in 1980s, became a huge hole in the 1990s, and continues to this day. Without taking action ozone layer would be thinner over much of the Earth exposing us to v high levels of UV radiation.
Science has known about the ozone layer for 100 years.