ACT State of the Environment 2007
Indicator: Ozone depletion
The ozone hole over the Antarctic continues to form each year, and reached a record size in 2006. According to current modelling, ozone levels will recover from the effects of man-made ozone depleting substances in the mid-latitudes by the middle of this century, with polar regions likely to recover one to two decades later.
In 2005 the Australian Government developed new regulations to control the manufacture and movement of ozone depleting substances.
What the results tell us about the ACT
The Antarctic ozone hole continues to form each year. The 2006 ozone hole – measured in September – was the largest on record since the NASA TOMS satellite measurements began in 1979 (WMO 2006). According to a 2006 United Nations Environmental Programme report the decline of ozone levels outside the polar regions has not continued from the levels of the 1980s and 1990s although global ozone is still less than in the 1970s. Ozone levels in the polar regions are, however, still showing much variability. According to current modelling, ozone will recover from the effects of man-made ozone depleting substances in the mid-latitudes by the middle of this century, with recovery likely in the polar latitudes one or two decades later (UNEP 2006).
The extent of ozone depletion in the ACT is not directly measured. Measurement of UV-B at ground level gives some indication of ozone levels although there are no data specifically for the ACT. UV-B is measured in Melbourne and Sydney, and also as part of a research project at Berridale in the New South Wales Snowy Mountains. Berridale data show the usual expected seasonal variation in UV irradiation.
The higher elevation and drier climate of the ACT, compared with Melbourne and Sydney, means the ACT is receiving higher levels of UV-B than either of those cities. Monitoring of UV-B radiation was discontinued in Canberra many years ago.
The Territory's most commonly used ozone-depleting substances have historically been chlorofluorocarbons (CFCs) and hydrochlorofluorocarbon (HCFC) used in refrigerators and air conditioners. As the manufacture and import of CFCs is now banned they are becoming increasingly scarce. Other substances are now used in its place. These substitute substances are continuously monitored to ensure they too are not harming the ozone layer. The CFCs that are removed from old refrigerators and air conditioners are purified and reused within the ACT for essential purposes that are appropriately licensed by the Australian Government.
In 2005 the Australian Government introduced regulations to the Ozone Protection and Synthetic Greenhouse Gas Management Act 1989. These regulations replaced state and territory legislation and control the manufacture, import and export of all ozone depleting substances and their synthetic greenhouse gas replacements. The Act also controls imports of refrigeration and air conditioning equipment containing an HFC or HCFC refrigerant (Department of Environment, Water, Heritage and the Arts).
Data sources and references
Dr Ken Green, of the New South Wales Department of Environment and Climate Change collected data from Berridale, New South Wales
Department of Environment, Water, Heritage and the Arts website at <http://www.environment.gov.au/atmosphere/ozone/legislation/index.html> last viewed 1 April 2008
United Nations Environment Programme (UNEP), Ozone Secretariat, Assessment Panels reports 2006 at <http://ozone.unep.org/Assessment_Panels/> last viewed 1 April 2008
United States of America Environmental Protection Agency (link from Commonwealth of Australia Department of Environment, Water, Heritage and the Arts website) at <http://www.epa.gov/ozone/snap/refrigerants/lists/indproc.html> last viewed 1 April 2008
World Meteorological Organization (WMO) 2006, Antarctic Ozone Bulletin No 7/2006 at <www.wmo.ch/pages/prog/arep/documents/ant-bulletin-7-2006_000.pdf>