Ozone future looks bright but huge hole hovers over pole
The seasonal hole in the protective ozone layer hovering above the South Pole is one of the biggest recorded in recent years but trends show an improvement can be expected in the long term.The holes above the poles fluctuate in size depending on the season.
The Antarctic's is still expanded and is expected to reach its maximum extent later this month.
The European Space Agency's Envisat satellite monitors global ozone layers and analysts have announced that its data from mid-August shows the southern hole is huge, covering an area roughly the size of Europe, or ten million square kilometres.
This is the third largest recorded area for this time of year in the past ten years, topped only by the figures from 1996 and 2000.
But despite the current doom-laden forecast, predictions for the long term future look good.
CFCs and other a wealth of other ozone depleting chemicals were banned under the Montreal Protocol, a global environmental treaty adopted in 1987.
But while levels of emissions have reduced dramatically there are still exemptions to the treaty, with industrial concerns top environmental ones.
One such exemption is for the use of harmful methyl bromide by the multi-billion dollar US soft fruits industry.
While such loopholes anger environmentalists there is strong evidence that the ozone layer will return to pre-industrial levels over the next 50 years.
Chlorine and bromine-based chemicals pumped into the atmosphere decades ago still linger on and their effects will persist for many years to come.
But American scientists analysing both satellite data and that from ground-based stations from 1978 to 2002 have published a study in the Journal of Geophysical Research saying we have now reached the turning point and levels are now beginning to creep back up.
If current trends continue, the researchers say, atmospheric ozone should have recovered to pre-CFC levels by 2050.
By Sam Bond