Scientists claim ozone layer is healing More than half the change attributed to ban on CFCs
![[Image: ozone_peak_october_2015.jpg]](http://s2.twnmm.com/images/en_ca/12/Ozone-Hole-Oct2-2015-59099.jpg%5Bimg%5D2000%5Bimg%5Dhttp://thewatchers.adorraeli.com/data/uploads/ozone_peak_october_2015.jpg)
2016
JULY 1, 2016
by: Pilita Clark, Environment Correspondent
Scientists say they have found the first firm signs that the thinning ozone layer over the Antarctic is starting to heal. The ozone hole was more than 4m square kilometres smaller in September last year than what it was in the year 2000, researchers say, an area nearly half the size of the US.
“We can now be confident that the things we’ve done have put the planet on a path to heal,” said Professor Susan Solomon of the Massachusetts Institute of Technology, lead author of a paper on the findings.
In the 1980s British scientists detected a striking thinning in the fragile ozone layer that filters out ultraviolet solar rays that can hasten skin cancers, cataracts and damage plants.
Some experts had predicted this might happen because of the growing use of synthetic chemicals known as chlorofluorocarbons (CFCs), then found in a huge range of products, from hairspray to deodorants and refrigerators.
These chemicals were progressively phased out after countries agreed to limit ozone-depleting substances in the 1987 Montreal Protocol, a measure often described as the world’s most successful environmental treaty.
The study, published in the Science journal, suggests more than half the shrinkage in the ozone hole is due to the reduction in atmospheric chlorine coming from CFCs. This is an indication of what global efforts can achieve, Professor Solomon said in an MIT report on the findings.
“Aren’t we amazing humans, that we did something that created a situation that we decided collectively, as a world, ‘Let’s get rid of these molecules’? We got rid of them, and now we’re seeing the planet respond,” she said.
Prof Solomon’s paper also suggests that although the ozone hole seems to be on a healing path, its recovery may be slowed because of the effects of volcanic eruptions.
The ozone hole in the Antarctic forms and expands during the southern hemisphere spring, between August and September, because of the high levels of chemically active forms of chlorine and bromine in the stratosphere.
It reached a record size in October last year even though atmospheric chlorine continued to decline. The researchers say this seemed to be mainly owing to the eruption of the Calbuco volcano in Chile.
Volcanic sulphate forms tiny particles that are the seeds for polar stratospheric clouds, leading to greater ozone loss. Some scientists say they are still not sure if the shrinking of the ozone hole revealed in the new paper is entirely owing to less chlorine in the stratosphere.
But others think that as chlorine levels continue to decline, the ozone hole may shrink and even close permanently.
“It will close by mid-century if we stay on the course we’re on,” said Dr Ryan Neely of the University of Leeds in the UK, a co- author of the new paper. He said his team’s research was groundbreaking.
“This is the first time we’ve been able to show the ban on chlorofluorocarbons that occurred with the Montreal Protocol has resulted in an actual increase in ozone,” he told the FT.
The ban has had unforeseen side- effects, however. As ozone-depleting substances were phased out, new chemicals known as hydrofluorocarbons, or HFCs, were developed for use in air conditioners, refrigerators, fire retardants and other products.
Although they do not harm the ozone layer, HFCs are potent greenhouse gases that linger in the atmosphere for many years if released and their use has grown in many countries.
They are the only group of greenhouse gases to have risen since 1990 in the EU, where overall emissions have fallen, according to a report published last week by the European Environment Agency.
2016
JULY 1, 2016
by: Pilita Clark, Environment Correspondent
Scientists say they have found the first firm signs that the thinning ozone layer over the Antarctic is starting to heal. The ozone hole was more than 4m square kilometres smaller in September last year than what it was in the year 2000, researchers say, an area nearly half the size of the US.
“We can now be confident that the things we’ve done have put the planet on a path to heal,” said Professor Susan Solomon of the Massachusetts Institute of Technology, lead author of a paper on the findings.
In the 1980s British scientists detected a striking thinning in the fragile ozone layer that filters out ultraviolet solar rays that can hasten skin cancers, cataracts and damage plants.
Some experts had predicted this might happen because of the growing use of synthetic chemicals known as chlorofluorocarbons (CFCs), then found in a huge range of products, from hairspray to deodorants and refrigerators.
These chemicals were progressively phased out after countries agreed to limit ozone-depleting substances in the 1987 Montreal Protocol, a measure often described as the world’s most successful environmental treaty.
The study, published in the Science journal, suggests more than half the shrinkage in the ozone hole is due to the reduction in atmospheric chlorine coming from CFCs. This is an indication of what global efforts can achieve, Professor Solomon said in an MIT report on the findings.
“Aren’t we amazing humans, that we did something that created a situation that we decided collectively, as a world, ‘Let’s get rid of these molecules’? We got rid of them, and now we’re seeing the planet respond,” she said.
Prof Solomon’s paper also suggests that although the ozone hole seems to be on a healing path, its recovery may be slowed because of the effects of volcanic eruptions.
The ozone hole in the Antarctic forms and expands during the southern hemisphere spring, between August and September, because of the high levels of chemically active forms of chlorine and bromine in the stratosphere.
It reached a record size in October last year even though atmospheric chlorine continued to decline. The researchers say this seemed to be mainly owing to the eruption of the Calbuco volcano in Chile.
Volcanic sulphate forms tiny particles that are the seeds for polar stratospheric clouds, leading to greater ozone loss. Some scientists say they are still not sure if the shrinking of the ozone hole revealed in the new paper is entirely owing to less chlorine in the stratosphere.
But others think that as chlorine levels continue to decline, the ozone hole may shrink and even close permanently.
“It will close by mid-century if we stay on the course we’re on,” said Dr Ryan Neely of the University of Leeds in the UK, a co- author of the new paper. He said his team’s research was groundbreaking.
“This is the first time we’ve been able to show the ban on chlorofluorocarbons that occurred with the Montreal Protocol has resulted in an actual increase in ozone,” he told the FT.
The ban has had unforeseen side- effects, however. As ozone-depleting substances were phased out, new chemicals known as hydrofluorocarbons, or HFCs, were developed for use in air conditioners, refrigerators, fire retardants and other products.
Although they do not harm the ozone layer, HFCs are potent greenhouse gases that linger in the atmosphere for many years if released and their use has grown in many countries.
They are the only group of greenhouse gases to have risen since 1990 in the EU, where overall emissions have fallen, according to a report published last week by the European Environment Agency.
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