Ozone hole affecting NZ slowly healing

23:09, Sep 09 2012
Adrian McDonald
University of Canterbury Antarctic expert Adrian McDonald, left, carries out a test in Antarctica as part of his research on how winds and circulation in the atmosphere impact ozone depletion.

The ozone hole affecting the Antarctic and New Zealand is slowly healing.

University of Canterbury Antarctic expert Adrian McDonald said the recovery was due to a reduction of ozone-destroying chlorofluorocarbons substances, which had been largely banned worldwide.

McDonald said it was unclear when the ozone would return back to natural levels but it was expected to be after 2050.

Ironically however, ozone depletion may have protected Antarctica from the worst of greenhouse gas-related warming, he said.

"With the ozone recovery the future of Antarctic climate is less certain. Though the complex interactions in the atmosphere associated with climate change makes this region particularly hard to predict," McDonald said.

''The future recovery of the Antarctic ozone hole and increases in greenhouse gases are expected to have opposite effects on the winds and circulation in the southern hemisphere.

"The increasing ozone hole has until now acted to change the circulation of the southern hemisphere so that the strong winds linked to the jet streams have moved towards the pole.''

He said ozone recovery should act to move the winds back towards the equator.

The jet streams positions are one of the main things that help control the width of tropical and polar weather belts, McDonald said.

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