Ozone hole repair ‘could take decades’
There are indications that the hole in the ozone layer is being repaired, but the process of recovery will take decades, according to a report published yesterday by the
The report, which aims to renew action on ozone, looks at the progress made in preventing the loss of “good ozone” that protects us from harmful ultra-violet radiation. It also highlights the fact that levels of “bad ozone” near the ground are rising - which it says will cause significant impact on humans - such as respiratory and cardiovascular disease – as early as 2030.
Published by the
Dr Hodgson, a specialist working with independent consultants Sci-Fact, warns that the ozone layer is still under threat from many ozone-depleting substances, especially rising levels of CFC replacement compounds, which could undermine the progress made in controlling damaging emissions through legislation.
He warns against complacency and calls for further international efforts to strengthen and extend the Montreal Protocol which sought to restrict the production and use of ozone-depleting chemicals such as chlorofluorocarbons (CFCs). He also says that scientists have a crucial role to play in driving political change in this area.
Hodgson said: “The Montreal Protocol is doing a pretty good job but I think that an element of complacency has crept in. Although 180 countries have signed up, only a couple of dozen have actually ratified it and the amendments which came along a few years later. The pressure needs to be kept up on the other countries to ratify it and other substances need to be brought under the
Evidence suggests that while the level of ozone-depleting chlorine is at or near its peak, levels of other ozone-depleting substances, such as bromine, is continuing to rise, the report says. There is uncertainty about the effects of some compounds designed to replace CFCs and for some damaging compounds, such as methyl bromide, there is currently no suitable replacement.
At the same time, global warming, which paradoxically is believed to lead to cooling in the stratosphere in the polar regions, is thought by many to be contributing to cloud formation of a kind which stimulates ozone depletion. The subtle interactions between global warming, ozone depletion and exposure to ultra-violet radiation are poorly understood and need further research, Hodgson says. He also warns that human behavioural patterns, such as people spending more time outdoors in the
The report explains that the total zone in the stratosphere is still declining, though at a slower rate than previously. It notes: “Despite the progress in limiting the emissions of ozone-destroying pollutants, the timescales of the atmospheric processes involved in ozone destruction mean that it will be decades before it can be judged whether the measures brought about by the Montreal Protocol have been completely successful and that the ozone layer is restored.”
But his report does emphasise that “the protective ozone layer remains under threat”. It warns: “The ozone ‘holes’ that appear annually at the polar regions are still large and long-lived; the possibility that climate change may bring conditions likely to cause even greater ozone loss is a contemporary danger.”
The entire report can be downloaded at http://policy.iop.org/Policy/Ozone%20Report.pdf