Hole in ozone layer on long road to recovery
The Earth’s protective ozone layer is well on track to recovery in the next few decades, according to a new assessment by 300 scientists, the first comprehensive update for four years. The recovery follows the ban on many ozone-depleting substances by the Montreal Protocol, agreed in 1987. They included HCFCs used for air-conditioning and refrigeration applications; the first C indicates chlorine, which destroys ozone. Refrigerants used today, with the exception of HCFC 22, do not contain chlorine. HCFC 22 has only a small ODP (ozone-depletion potential).
The ozone layer protects the Earth against ultra-violet radiation from the Sun. UNEP (United Nations Environment Programme) reckons that the protocol will have prevented two million cases of skin cancer a year by 2030, averted damage to human eyes and immune systems and protected wildlife and agriculture.
An assessment for decision makers, a summary document of the ‘Scientific assessment of ozone depletion 2014’ is being published by UNEP and the World Meteorological Organisation (WMO).
Achim Steiner, UN under-secretary general and UNEP executive director, said, ‘There are positive indications that the ozone layer is on track to recovery towards the middle of the century. The Montreal Protocol — one of the world’s most successful environmental treaties — has protected the stratospheric ozone layer and avoided enhanced UK radiation reaching the Earth’s surface.’
The UK’s Royal Meteorological Society explains that the Antarctic ozone hole still occurs each spring and is expected to continue for some time.
However, this recent assessment indicates it is in recovery and should reach the 1980 benchmark — the time before significant ozone depletion — before the middle of the century in mid-latitudes and the Arctic, but somewhat later in the Antarctic.
Michel Jarraud, secretary-general of the WMO, said, ‘International action on the ozone layer is a major environmental success story. This should encourage us to display the same level of urgency and unity to tackle the even greater challenge of climate change. This latest assessment provides solid science to policy makers about the intricate relationship between ozone and climate and the need for mutually supportive measures to protect life on Earth for future generations.’
