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Sci/Tech
25th Anniversary of the Discovery of Ozone Hole
Author: British Antarctic Survey
Published on May 6, 2010 - 7:22:11 AM

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May 5, 2010 - This week British Antarctic Survey (BAS) commemorates the 25th anniversary of one of its most dramatic scientific discoveries - the ozone hole.

In May 1985 reporting in Nature Joe Farman, Brian Gardiner and Jonathan Shanklin described their observations of large losses of ozone over Antarctica. In this week's Nature Jonathan Shanklin reflects on how the discovery was made and what lessons were learnt.

As part of the anniversary commemorations Jonathan Shanklin appears alongside Nobel Prize winner Paul Crutzen and leading US scientists David Fahey and Susan Solomon at a special international symposium organised by Cambridge University on Friday 7 May. The event will be web cast live at Antarctic Ozone Hole: Then and Now on the website of the European Ozone Research Coordinating Unit: http://www.ozone-sec.ch.cam.ac.uk/

The discovery of the ozone hole alerted the world to the dramatic and major environmental threat. The accumulation of chlorofluorocarbons (CFCs) used in refrigeration and air conditioning systems, and industrial solvents were found to deplete the protective layer of ozone that surrounds the Earth. Action by governments around the world led to the 1987 Montreal Protocol and its amendments, which ensured that production and consumption of CFCs, halons and carbon tetrachloride were phased out by 2000, and methyl chloroform by 2005. All members of the United Nations have now signed the Montreal Protocol. Today, scientists predict that Antarctic ozone levels will return to their 1950s levels by about 2080.

Jonathan Shanklin said, "This discovery was a crucial reminder of the importance in investing in long-term monitoring, but perhaps the most startling lesson from the ozone hole is just how quickly our planet can change."

To mark the occasion BAS has published a new public information leaflet, The Ozone Hole: http://www.antarctica.ac.uk/about_bas/publications/bas_the_ozone_hole.pdf

The Antarctic ozone hole is caused by chlorine and bromine in the atmosphere, which come from chlorofluorocarbons (CFCs) and halons. The hole itself begins to form when sunlight returns at the end of the Antarctic winter, and reaches its largest extent every September, before disappearing again by mid summer. The amount of ozone overhead should follow a regular seasonal pattern. This is what occurred during the first 20 years of BAS measurements, but by the late 1970s clear deviations were observed. In every successive spring the ozone layer was weaker than before, and by 1984 it was clear that the Antarctic stratosphere was progressively changing.

British Antarctic Survey (BAS), a component of the Natural Environment Research Council, delivers world-leading interdisciplinary research in the Polar Regions. Its skilled science and support staff based in Cambridge, Antarctica and the Arctic, work together to deliver research that underpins a productive economy and contributes to a sustainable world. Its numerous national and international collaborations, leadership role in Antarctic affairs and excellent infrastructure help ensure that the UK maintains a world leading position. BAS has over 450 staff and operates five research stations, two Royal Research Ships and five aircraft in and around Antarctica.

Paul Crutzen, Mario Molina and Frank Sherwood Rowland were awarded the Nobel Prize for Chemistry in 1995 for their work on ozone depletion.

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