News in Science

The hole in the ozone layer: 25 years on

This year marks 25 years since the publication of a paper confirming the existence of an ozone 'hole' above Antarctica, which soon led to an international treaty banning the use of certain chemicals.

Jonathan Shanklin head of meteorology and ozone monitoring at the British Antarctic Survey was one of the authors of the paper published in the science journal Nature.

"It was about just over 30 years ago that I joined the Antarctic Survey," says Shanklin.

"Early on one of the jobs I was given was helping to process the ozone data that was coming in from our Antarctic stations."

The ozone layer, which resides in the lower layers of the stratosphere (13 to 20 kilometres above the Earth's surface), prevents dangerous amounts of ultraviolet light reaching the Earth's surface.

Shanklin says, "There had been lots of concern that Concord and spray cans might destroy the ozone layer so I thought I would try and reassure people that nothing was happening."

But when he compared that year's data with data from 20 years ago he found there had been a clear change in the Antarctic spring.

'Exciting' find

"What we had to do was go back through the missing 10 years of data and then I was able to demonstrate that it was systematic," says Shanklin.

"The Americans went back to their satellite data and said 'whoops, yes you're right'.

"There was indeed a large hole above the Antarctic forming each spring, and that was really the discovery. So [it was] an exciting period."

Although the discovery may have seemed exciting at first, there was soon the realisation that the hole may have a direct impact on humans.

"Having a hole really sounds bad. You've got to do something about it - you've got to fill in a hole," says Shanklin.

"Also the link between increased UV and skin cancer meant that there was great public concern about the issue. Equally the manufacturers had a relatively simple solution towards finding replacements.

In 1987, the Montreal Protocol was signed, which led to the phasing out of chemicals responsible for creating the ozone hole, such as chlorofluorocarbons and hydrochlorofluorocarbons.

"Everything fell into place really quite easily to get a coordinated response."

Greenhouse gases

Despite the apparent deadlock in seeking an agreement to reduce the rate of greenhouse gas emissions, Shanklin believes one will eventuate.

"It's quite clear that once the political will is there a solution can be found. I think the key thing is getting that political will in place," he says. "Sadly I fear that what it will take is a disaster that swings public opinion towards making changes."

"I hope it doesn't occur. I hope that the politicians will sign up to a binding and lasting international treaty because that would be the best solution for the present and for the future generations."