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Australia's net greenhouse gas emissions(a)
According to the estimates produced by the accounting rules of the Kyoto Protocol, Australia’s total greenhouse gas emissions in 2001 were about 4% higher than they were in 1991.
Per capita, we have one of the world’s highest levels of greenhouse gas emissions, although our per capita emissions are decreasing, as are our emissions per $ of GDP. Our heavy reliance on fossil fuel burning for energy rather than other forms of power (such as nuclear or hydro-electricity), the structure of our economy and our changes in Australian land use are three influences behind our high rate of emissions.
Progress and the headline indicator
The health of our environment depends largely on the actions of Australians. But some environmental concerns transcend national boundaries: our environment can be influenced by the actions of other countries, and we, in turn, can influence other countries' environments. Our contribution to these international concerns is an important aspect of progress. Global warming is widely perceived as the most significant international environmental concern and Australia's greenhouse gas emissions are the focus of the headline indicator. We also look at Australia's ozone depleting emissions.
The main gases in the atmosphere, nitrogen and oxygen, are almost completely transparent to the sun's rays. But water vapour, carbon dioxide and other gases form a blanket around the Earth, trapping heat - a process called the greenhouse effect. Human activity is increasing atmospheric concentrations of existing greenhouse gases (such as carbon dioxide and methane) and adding new gases such as chlorofluorocarbons (CFCs). Many experts believe that these gases are linked to global warming and climate change by way of an enhanced greenhouse effect.2
Data beginning in 1910 show that annual mean temperatures in Australia have increased (although this has not been uniform);3 while the World Meteorological Organization reports that global temperatures in 1998, 2002 and 2003 were the three warmest since records began in 1861.4 In Australia, 1998 is the hottest year since records began (in 1910), and 2003 was the sixth hottest.
The Intergovernmental Panel on Climate Change (IPCC) has developed a range of scenarios that provide projects of future climate change, some of which suggest significant global warming. The construction of IPCC scenarios is ongoing, and some have expressed concerns about their economic and statistical underpinning.5
The headline indicator presents Australia's total net greenhouse emissions. It estimates our total emissions, less any credits from greenhouse sinks, between 1991 and 2001. Estimates of Australia's emissions vary according to the accounting conventions used. Unless otherwise indicated, the emission estimates produced using the Kyoto accounting rules are used here. These estimates are higher than those calculated for the United Nations Framework Convention on Climate Change (UNFCCC), although changes over time are broadly similar (the difference relates to the treatment of forest sinks).6
Australia's total net greenhouse emissions in 2001 were almost 543 megatonnes (Mt) CO2-e1, an increase of 4.4% since 1991. Emissions rose gradually over the period, with the sharpest rise between 1997 and 1998 when emissions from land use change rose by more than 10% rather than fall as they had done during most of the decade.
CO2-e emissions, net, per capita and per $ GDP
However, Australia's population has grown by rather more than that over the past 10 years, and Australia's per capita emissions declined by about 8% over the period. The economy is also becoming less emissions-intensive, with emissions per $ of GDP declining by more than a quarter.
In order to compare countries of different population size, one can consider per capita emissions of greenhouse gases; almost 28 tonnes of CO2-e were produced for every Australian in 2001. These figures are high by international standards. Our per capita emissions of CO2 (the main greenhouse gas) from fossil fuel burning, for instance, are among the highest in the world. In 2001 about 19 tonnes of CO2 were emitted for every Australian: only America, among the OECD members, had higher per capita emissions of CO2.
Australia's large per capita emissions in part reflect our heavy use of coal in electricity generation: according to OECD estimates for 2001, about 55% of Australia's carbon dioxide (the main greenhouse gas) emissions arose in the production of public electricity and heat, a higher proportion than any other OECD member. Some 35% of the OECD's entire CO2 emissions were generated for this purpose.13 Unlike most OECD members, Australia does not use nuclear power to generate electricity.
Factors influencing change
The size of the economy, its structure and the energy intensity of industries are important determinants of emissions. And it is informative to consider changes in the contribution of different sectors over time.
The 4% rise in emissions over the period 1991 to 2001 has primarily been driven by a larger rise (28%) in emissions from the energy-sector. This rise has been partially offset by a significant decline (73%) in net emissions attributable to land use and land use change (this in turn comes from a reduction in emissions from land clearing).
In 2001 the energy sector (mainly power stations and transport) accounted for 68% of net emissions, up from 55% in 1991, with emissions from energy industries (primarily from coal-fired electricity generating stations) increasing by over 36% since 1991. ABS figures from the mid-1990s show that more than half of this sector's greenhouse gases were emitted as a consequence of the production and/or consumption of goods and services used by households (particularly domestic electricity and motor vehicle fuel), and about a quarter of emissions were generated in the production of goods and services for export.14
Agriculture was the second largest emitter, and accounted for one-fifth of total net emissions in 2001 (mainly methane from livestock). Emissions from this sector rose by 11% over the period.
Land use and land use change activities emitted about 37 Mt CO2-e, and forest sinks consumed about 11 Mt CO2 during 2001 to produce a net emission of almost 26 Mt CO2-e. (Strictly speaking however, the credits from plantations established in Australia since 1990 are not officially accounted for until 2008-2012).6
Other things being equal, economic growth arising from industries that are emissions-intensive (such as iron, steel and aluminum smelting) will increase greenhouse gas output more than growth in sectors such as service industries which are less energy- and emissions-intensive.
Australia’s Greenhouse emissions(a), by category
Carbon Dioxide Measurements(a)
The price of energy also has an influence in managing demand. Electricity prices fell in Australia during recent years, while the relatively low cost of vehicle fuel here helps to explain why our cars are larger, less fuel efficient and driven more than in many other countries.15
Reducing greenhouse gas emissions has become the subject of major international negotiations. In 1992, Australia ratified the UNFCCC, which sought to stabilise greenhouse gas concentrations in the atmosphere. The convention was updated by the Kyoto Protocol of 1997, which Australia signed but has not yet ratified. Under the protocol, developed countries agreed to accept greenhouse gas emission targets. Australia's target is to restrict annual average emissions over the period 2008 to 2012 to no more than 8% above their 1990 level.
Ozone depleting emissions
Ozone near the Earth's surface can be a harmful pollutant, but in the upper atmosphere (the stratosphere) it absorbs most of the harmful ultraviolet (UV) radiation in the sun's rays. When excessive UV radiation reaches the Earth's surface it can cause health problems to people and other organisms, including damage to the eyes, skin and immune system. It can also affect crop yields and marine plankton (which might have flow-on effects to many marine ecosystems). Radiation can degrade plastics, wood, paper, cotton and wool.
Certain substances trigger the destruction of ozone. Human activity has been responsible for increasing the concentrations of these substances in the upper atmosphere: the main ozone depleting emissions are chlorofluorocarbons (CFCs) used in refrigeration, foam plastics and aerosol products.
As a result of these emissions, between 2% and 4% of ozone over Australia has been lost each decade since the 1950s, and we are now exposed to greater levels of UV radiation than in the past.17 There was international recognition of the problem in the mid-1980s when most countries signed the Montreal Protocol governing the global consumption of ozone depleting substances.
Since then the accumulation of ozone depleting substances in the atmosphere has slowed. Concentrations peaked in the mid-1990s and are now declining. But the substances already in the atmosphere continue to destroy ozone, and because of these time lags the depletion of ozone over Australia and Antarctica may not yet have peaked, although ozone may not decline much further.17 The largest losses have been observed over Antarctica (more than 60% of natural levels)17 particularly in spring, losses that have led to the so-called Antarctic ozone 'hole', an area of the stratosphere within which ozone concentrations are well below levels at which they were at the beginning of the twentieth century.17
Consumption of ozone depleting substances in Australia
Some scientists expect that complete ozone recovery may be achieved by about 2050, although it may be delayed by as much as 50 years by climate change.17 Greenhouse gases trap heat in the lower atmosphere, thereby keeping the stratosphere cooler. At very low temperatures, certain stratospheric clouds form above the poles, and in spring they react with ozone depleting substances which then destroy ozone.
Estimates of Australia's total consumption of ozone depleting substances, weighted according to the ozone depleting potential of each, are presented in the graph. Consumption in 1991 was over 8,000 ozone depleting potential tonnes (ODPTs: an aggregated scale of measurement which allows one to add together quantities of different gases and weights them according to the amount of ozone each could potentially deplete). In 2001, it had fallen, in response to international restrictions, to 362 ODTs, mostly composed of methyl bromide and hydrochlorofluorocarbons (HCFCs).
Australia stopped production of CFCs during the 1990s, and we are ahead of the Montreal Protocol's schedule in reducing our use of HCFCs, which are minor ozone depleting substances that are used as interim replacements for CFCs.
Links to other dimensions of progress
Greenhouse gas emissions and climate change are more than an environmental concern. While Australia's biodiversity and freshwater ecosystems might be affected by climate change, global warming could - if certain scenarios of the International Panel on Climate Change prove correct - have profound consequences for our economy and society (increasingly frequent and severe floods and rising sea levels, for instance, have the potential to cause significant damage).
Emissions are linked to economic activity, through the burning of fossil fuels, certain industrial processes, agriculture and forestry. However, the development and adoption of new low-emissions technology, such as wind power, might play an important role in reducing emissions in the future.
See also the commentaries National income, The human environment and Transport.