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Ozone hole over Antarctica smallest in last decade

Last Updated: Saturday, February 9, 2013 - 10:48

Washington: Satellite images show that the recent ozone hole discovered over Antarctica was the smallest seen in the past decade.

Long-term observations also reveal that Earth`s ozone has been strengthening following international agreements to protect this vital layer of the atmosphere.

According to the ozone sensor on Europe`s MetOp weather satellite, the hole over Antarctica in 2012 was the smallest in the last 10 years.

The instrument continues the long-term monitoring of atmospheric ozone started by its predecessors on the ERS-2 and Envisat satellites.

Since the beginning of the 1980s, an ozone hole has developed over Antarctica during the southern spring - September to November - resulting in a decrease in ozone concentration of up to 70 percent.

Ozone depletion is more extreme in Antarctica than at the North Pole because high wind speeds cause a fast-rotating vortex of cold air, leading to extremely low temperatures.

Under these conditions, human-made chlorofluorocarbons - CFCs - have a stronger effect on the ozone, depleting it and creating the infamous hole.

Over the Arctic, the effect is far less pronounced because the northern hemisphere`s irregular landmasses and mountains normally prevent the build-up of strong circumpolar winds.

Reduced ozone over the southern hemisphere means that people living there are more exposed to cancer-causing ultraviolet radiation.

International agreements on protecting the ozone layer - particularly the Montreal Protocol - have stopped the increase of CFC concentrations, and a drastic fall has been observed since the mid-1990s.

However, the long lifetimes of CFCs in the atmosphere mean it may take until the middle of this century for the stratosphere`s chlorine content to go back to values like those of the 1960s.


First Published: Saturday, February 9, 2013 - 10:48

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