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Monday, 3 November 2003
Page: 21804


Dr WASHER (7:24 PM) —I rise today to speak to the Ozone Protection and Synthetic Greenhouse Gas Legislation Amendment Bill 2003 and related bills. The purpose of the bills is to amend the Ozone Protection Act 1989 to maintain the national regulatory scheme for the management of both ozone-depleting substances, ODSs, and newer synthetic greenhouse gases, SGGs, to be used as their replacements. Australia's ozone protection legislation has made a significant contribution to the global effort to phase out ozone-depleting substances. Through cooperation between government and industry the legislation has reduced Australia's consumption of ozone-depleting substances by over 80 per cent since its enactment in 1989.

To achieve this reduction, Australian industry has adopted a variety of ozone benign substances and technologies, including the use of synthetic greenhouse gases, hydrocarbons and fluorocarbons. These gases do not endanger the ozone layer but are now recognised as potent greenhouse gases. Some of these SGGs have an impact on the climate hundreds to thousands of times greater than emissions of carbon dioxide on a tonne-for-tonne basis. For example, the hydrofluorocarbon 134a is 1,300 times more potent than carbon dioxide on a tonne-for-tonne basis.

The bills also extend the system in the existing legislation for licensing the import, export and manufacture of ozone-depleting substances. This enables Australia to ratify the most recent amendment to the Montreal protocol—the Beijing amendment—and address environmental issues raised by the increasing adoption of SGGs where they are used as alternatives to ODSs. These amendments have been developed following extensive consultation with state and territory governments, industry and other stakeholders over the last four years. There is widespread support for these changes, which will allow a national uniform approach and deliver effective environmental gains, certainty and consistency as a benefit to industry. These amendments affect businesses in the airconditioning, refrigeration, foam, fire protection, fumigation in agriculture, aerosol and precision cleaning industries. Greenhouse gases emitted during the production of aluminium, magnesium and electricity are exempted from the bill and will be addressed through voluntary programs.

The bills have the potential to reduce Australia's overall emissions of greenhouse gases by the equivalent of six million tonnes of carbon dioxide per annum by 2010, or up to one per cent of 1990 levels. The bills cover the phasing out of these ozone-depleting substances: bromochloromethane, hydrochlorofluorocarbons, chlorofluorocarbons, hydrobromofluorocarbons, halons, methyl bromide, carbon tetrachloride and methyl chloroform.

Hydrocarbons, which are used as an alternative to ozone-depleting substances in car airconditioners, are neither ozone depleters nor greenhouse gases and are not regulated by this regulation. However, hydrocarbons are flammable and in some applications raise occupational health and safety issues. The aim of the bill is not to phase out SGGs as there is no reasonable number of alternative substances available to replace them. They were originally adopted as replacements for ozone-depleting substances. The aim of the bill is to minimise the emission of these gases. The earth's ozone layer protects all life from the sun's harmful radiation, but human activities releasing ozone-depleting substances have damaged the shield.

Ozone is an extremely rare gas, representing three out of every 10 million molecules. Most atmospheric ozone is concentrated in a layer in the stratosphere about 15 to 30 kilometres above the earth's surface. Ozone is a molecule containing three oxygen atoms. It is blue in colour and has a strong odour. The oxygen molecule, which we breathe, has two oxygen atoms and is colourless and odourless.

The ozone layer absorbs a portion of the radiation from the sun, preventing it from reaching the planet's surface. Most importantly, it absorbs the portion of ultraviolet light called UVB, a band of ultraviolet radiation with wavelengths from 280 to 320 nanometres, a nanometre being one billionth of a metre. It is produced by the sun. UVB has been linked to many harmful effects, including various types of skin cancer, cataracts and harm to crops, certain materials and some forms of marine life. The ozone layer also absorbs all the lethal ultraviolet C radiation.

At any given time, ozone molecules are constantly formed and destroyed in the stratosphere. The amount, however, remains relatively stable. The ozone depleting substances that have been used over the past 50 years or so were initially thought of as miracle substances. They were stable, non-flammable, low in toxicity and inexpensive to produce. Over time, CFCs found uses in refrigerants, propellants, solvents, foam-blowing agents and other small applications. Others—such as chlorine-containing compounds including methyl chloroform, a solvent, and carbon tetrachloride, an industrial chemical used in fumigation; halons, which were found to be extremely effective fire-extinguishing agents; and methyl bromide, a very effective soil fumigant—have atmospheric lifetimes long enough to allow them to be transported by winds into the stratosphere.

The CFCs are quite stable, although on exposure to strong ultraviolet radiation they break down and release chlorine and bromine, which in turn attack and destroy ozone. One chlorine atom can destroy over 100,000 ozone molecules. The net effect is to destroy ozone faster than it is naturally created. One example of ozone depletion is the annual ozone `hole' over Antarctica that has occurred during the Antarctic spring since the early 1980s. Rather than being a literal hole through the layer, the ozone hole is a large area of the stratosphere with extremely low amounts of ozone. Ozone levels have fallen by over 60 per cent during the worst years. In addition, research has shown that ozone depletion occurs over the latitudes that include North America, Europe, Asia and much of Africa, Australia and South America. Thus ozone depletion is a global issue and not just a problem at the South Pole.

Data collected in the upper stratosphere has shown that there has been a general thinning of the ozone layer over most of the globe. This includes a five per cent to nine per cent depletion over Australia since the 1960s. In addition to this general thinning, more dramatic damage occurs over Antarctica each spring when the ozone hole forms. The 2000 ozone hole was the largest on record, measuring 32.9 million square kilometres—more than three times the size of Australia—and, for the first time, extending over populated areas.

The prospects for the long-term recovery of Antarctic ozone are good. Non-essential consumption of the major ozone-depleting substances in the developed world slowed during the early 1990s and ceased in 1996. Stratospheric chlorine levels should return to pre ozone hole levels by about 2050.

Since most of the ozone-depleting substances are released in the northern hemisphere, a common question is why the ozone hole occurs over Antarctica. The first part of the answer is that, even though most of the chemicals are heavier than air, regardless of where they are released, they mix throughout the troposphere—the layer extending up to about 15 kilometres above the earth's surface—over about a year and then mix into the stratosphere in two to five years. The second part of the answer is that, although the overall process is similar between global ozone depletion and the ozone hole, there are two different types of ozone depletion chemistry. Both types are important, but the ozone hole seems to grab most of the attention.

The first kind is called homogeneous depletion. Resulting from reactions as gases mix together, it is responsible for the reduction in global ozone levels. The five per cent to 10 per cent drop in ozone over the US is an example of homogeneous chemistry. The second kind of ozone depletion chemistry, called heterogeneous, causes the radical destruction of ozone over the Antarctic each spring that we call the ozone hole. It results from chemical reactions on the surfaces of ice particles. The existence of these particles and the seasonal and geographic location of the hole all result from a combination of meteorological and other effects that are specific to Antarctica at that time of year.

Each winter, the air around the South Pole cools and begins circulating to the west. This vortex effectively isolates the air over Antarctica, with three effects. First, outside air, which is relatively ozone rich, cannot mix in and sustain ozone levels. Second, the chemicals that tend to slow down the depletion reactions cannot mix with Antarctic air. Third, the heat from outside air is shut out, prolonging the period of very low stratospheric temperatures. Because the air gets so cold over Antarctica each winter, the vortex remains intact for several months, finally breaking up in December. The vortex is the reason for the timing and location of the ozone hole, because such vortices do not form over more temperate regions, and, as such, homogeneous gas phase chemistry is the dominant global concern, producing long-term ozone depletion trends.

The Antarctic is a very cold place; temperatures in the lower stratosphere drop below minus 80 degrees Celsius. Ordinarily, the stratosphere is so dry that it will not support clouds, but these cold temperatures do produce ice clouds, called polar stratospheric clouds or PSCs. Some of the clouds are water ice, but more prevalent are clouds of nitric acid and water. Like the wind vortex, the formation of PSCs has specific impacts. In the absence of polar stratospheric clouds, most man-made stratospheric chlorine is locked up in relatively inert compounds. However, the surfaces of the ice particles in the clouds allow these compounds to react, converting the chlorine into ozone-destroying forms. These reactions are different from those occurring when gases mix over mid latitudes.

The forms of chlorine released from the clouds' surfaces cannot destroy ozone without the addition of UV light, which is not available during the southern winter. Thus their concentrations rise until the sun appears during the spring. When the sun does rise, the chlorine is rapidly converted to chlorine monoxide, and this is followed by a very rapid set of reactions, destroying up to 70 per cent of the ozone in the lower stratosphere over a period of a few weeks.

The net effect of these factors is the ozone hole, an easily measured, well defined seasonal phenomenon. The depth, area and timing of the hole vary from year to year, but, as the polar vortex breaks up and the stratosphere warms, the heterogeneous chemistry shuts down and ozone levels over the Antarctic return to near normal. The ozone hole generally lasts from September to December, although the exact time period varies from year to year. The ozone hole is the most obvious effect of the release of ozone-depleting substances into the atmosphere and is also the most extreme example of ozone depletion. However, the long-term downward trends in ozone levels over most of the globe also pose a serious threat. Although not as spectacular, homogeneous chemistry is a significant problem.

In conclusion, the 1999 Beijing amendment has already essentially been practised by Australia. The Beijing amendment contains four key elements: the ban on production and trade in bromochloromethane except for essential uses to countries that have ratified the Beijing amendment; the ban on trade in hydrochlorofluorocarbons with countries who have not agreed to phase out these gases; the phase-out schedule for hydrochlorofluorocarbon production in developed countries, with phase-out by 2040; and mandatory annual reporting of methyl bromide imported for quarantine and preshipment purposes. Australia's trade in hydrochlorofluorocarbons with countries who have not agreed to phase them out is negligible. Australia has voluntarily reported its quantity of methyl bromide imported for quarantine and preshipment purposes. Australia does not manufacture bromochloromethane or hydrochlorofluorocarbons, has not recently exported bromochloromethane, and on average imports less than one kilogram of bromochloromethane per year. So, basically, we have enacted this already.