Ozone hole in recovery
Q. How large is the hole in the ozone layer above Antarctica now compared to its worst point, and what is driving the change?
Olaf Morgenstern, the principal scientist at the National Institute of Water and Atmospheric Research (Niwa), said despite ozone-depleting substances reaching a maximum point in the stratosphere in 2000, research showed the Antarctic ozone hole was now on the road to recovery.
‘‘The ozone layer is responding to considerable reductions in the emissions of chlorine and bromine compounds that are the result of the Montreal Protocol of 1987,’’ he said.
‘‘Due to year-to-year variations in its size and depth, this recovery had not been seen with certainty before.
‘‘The ozone hole, which opens up every Antarctic spring since at least the 1980s, usually reaches
A.
''The ozone layer is responding to considerable reductions in the emissions of chlorine and bromine ..."
about 20 million square kilometres. For comparison, the Antarctic continent is 14 million sq km in size and New Zealand 0.27 million sq km.’’
Morgenstern said the hole was expected to close, assuming continued compliance with the Montreal Protocol, in about 2060.
‘‘New Zealand has never been under the ozone hole. Here, the ozone layer is perhaps a little thicker than it used to be, but not by much. It’s naturally relatively thin compared to the Northern Hemisphere, and in summer, particularly fair-skinned people need to take care in the sun.’’