There was a crash in the production of chlorofluorocarbons (CFC) following the signing of the Montreal Protocol in 1987.
By 1999 atmpospheric levels of manmade ozone destroying chemicals had leveled off and since 2003 there has been a 7 percent drop in the amount of chlorine and bromine in the lower stratosphere (10-25 km). This is apparently where most ozone loss occurs.
Given its original objectives, the Montreal Protocol has been a huge success and reduced concentrations of ozone-depleting gases.
The United Nations Environment Programme (UNEP) has been predicting for some time that the reduction in concentrations of ozone-depleting gases will result in a recovery in the ozone layer and also the Antarctic ozone hole.
So what happened this year?
Over the last few weeks we have heard report after report that the ozone hole over the Antarctic has expanded to a near-record size despite the successful global ban on chlorofluorocarbons.
An incredible 40 million tonnes of ozone had been lost over Antarctica this year, exceeding the record 39 million tonne loss in 2000 with the depth of the ozone hole now rivaling the record low ozone values of 1998.
Discussion, including at this blog, has focused not on chlorofluorcarbons as the cause of the now growing ozone hole, but on atmospheric temperatures and other phenomena.
It is interesting to reflect on what some skeptics were writing 10 years ago.
At that time S. Fred Singer was sounding something like a global warming skeptic with his piece entitled ‘Ozone politics With a Nobel imprimatur’ in the Washington Post.
He wrote: “Further research will likely prove the CFC-ozone issue to have been a minor environmental problem. In the meantime, hasty policies to ban CFC production by the end of 1995, though a financial windfall for chemical companies and appliance manufacturers, will impose substantial economic costs — up to $100 billion — on U.S. consumers and make life worse for the poorest everywhere — especially in developing nations.”
There is even mention of hurricanes and Al Gore in the article.
Anyway, it is interesting to ponder why, given the success of the Montreal Protocol, there has not been a reduction in the hole over the Antarctic?
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Thanks to Bob Foster for sending me the S. Fred Singer paper.
A note to commentators, I am interested in better understanding this issue and I’m interested in your opinion. But comments that don’t add new information and/or that are disrespectful may be edited and /or deleted.
Jennifer Marohasy BSc PhD has worked in industry and government. She is currently researching a novel technique for long-range weather forecasting funded by the B. Macfie Family Foundation.