How much Australia emits
Australia's net emissions across all sectors, including emissions from land use, land use change and forestry (LULUCF), totalled 576.2 million tonnes of carbon dioxide equivalent (Mt CO2-e) in 2008. Emissions fell off sharply in that year due to the global financial crisis, but have otherwise followed a steady upward trend.
The energy sector is the largest source of greenhouse gas emissions, comprising 72.3 per cent of net emissions. This proportion is less than in many countries due to the relatively large contribution from the agriculture and land use, land use change and forestry sectors to Australia's total emissions. The industrial processes and waste sectors are relatively minor sources.
Carbon dioxide equivalent, CO2-e, provides the basis for comparing the warming effect of different greenhouse gases.
Source and further detail: Department of Climate Change, National greenhouse gas inventory, 2010, p. 27
Carbon dioxide (CO2) is produced by the combustion of any carbon-containing substance. The majority of CO2 emissions in Australia arise from the combustion of fossil fuels (also known as hydrocarbon fuels). These are coal, oil and its derivatives (such as petrol), and methane gas (also called natural gas). Electricity generation (which in Australia relies mainly on coal) is the largest single contributor to CO2 emissions, at 37.2 per cent of inventory emissions.
Of course, CO2 is not the only greenhouse gas, another is methane. Most methane emissions come from livestock farming, extraction of fossil fuels, wet rice cultivation, biomass, burning landfill, and domestic sewage. The agriculture sector accounts for the majority of methane emissions, most of which are formed by the process of fermentation of feedstuffs that occurs in the digestive systems of large herbivores. Methane is also released by composting and by the decomposition of animal wastes. Smaller quantities are generated through rice cultivation, burning of savannahs to increase grass production, and field burning of crop residues. Fugitive emissions from fuels also contribute to methane emissions, mainly from the mining of coal. Another significant contributor to methane emissions is the waste sector, generated from anaerobic decomposition of organic matter in landfills.
Other greenhouse gases—halocarbons—are used in a wide range of industrial processes, and in consumer goods including aerosol propellants, refrigerants, foam-blowing agents, solvents, and fire retardants. Also, nitrous oxide is produced by a range of human activities including nylon and nitric acid production, soil cultivation and the use of commercial and organic fertilisers in agriculture, burning of organic matter, fuel combustion and catalytic converters in cars. The oceans and rainforests also naturally produce nitrous oxide. Nitrous oxide is the main regulator of stratospheric ozone and one of six gases addressed by the Kyoto Protocol.
Overall, greenhouse gases are given off by processes and activities from:
The energy sector—This includes stationary energy, transport, and fugitive processes. Stationary energy is the largest contributor to energy sector emissions, which are themselves the largest contributor to how much Australia emits. Stationary energy includes emissions from fuel consumption for electricity generation, fuels consumed in the manufacturing, construction and commercial sectors, and other sources like domestic heating. The stationary energy sector makes up 51.4 per cent of Australia's emissions. Electricity generation is by far the largest source of emissions in this sector, contributing close to 50 per cent of all energy emissions. The remainder of emissions from stationary energy sector comes from direct combustion of fuels.
Transport includes emissions from the direct combustion (or end-use emissions) of fuels by road, rail, domestic air transport and domestic shipping. Road transport comprises passenger vehicles, light commercial vehicles, trucks, buses and motorcycles. Domestic air transport comprises commercial passenger and light aircraft on domestic routes using either aviation gasoline or jet kerosene (international air transport is reported but not included in Australia's total emissions in line with international guidelines). Coastal shipping consists of domestic shipping and small craft (international shipping is reported but not included in Australia's total emissions in line with international guidelines). Rail transport includes diesel freight trains. However, electric rail is included under electricity generation. Hence, under this measure, the public rail transport network in Sydney, which is electrified, has zero transport emissions. Transport sector emission projections are highly dependent on key forecast variables including economic and demographic indicators such as oil price, GDP and population forecasts, vehicle technology and the future travel behaviour of individuals. Contrary to popular perceptions, the transport sector contributes relatively little to greenhouse emissions.
The fugitive sector includes METHANE, CARBON DIOXIDE and NITROUS OXIDE emissions from the production, processing, transport, storage and distribution of raw fossil fuels (coal, oil and gas). The fugitive emissions sector includes generally deliberate but not fully controlled emissions that typically result from leaks, including those from pump seals, pipe flanges and valve stems. Fugitive emissions also include methane emitted from coal mine seams. During petroleum storage tank filling, venting loss of vapour is a fugitive emission . Projected growth in emissions in the fugitive sector results mainly from projected increases in the production and export of both black coal and natural gas.
Industrial processes—The industrial processes sector covers non-energy emissions from mineral processing, the chemical industry, metal production, industries covered by the Montreal Protocol on Substances that Deplete the Ozone Layer (refrigeration and air-conditioning, FOAM BLOWING, fire protection, aerosols and solvents) and SULPHUR HEXAFLUORIDE used in electrical circuit breakers and switchgear.
Agriculture—Agriculture emissions are mostly in the form of methane and nitrous oxide from enteric fermentation in livestock, manure management, rice cultivation, agricultural soils, savannah burning and field burning of agricultural residues. The size of the beef herd is the main driver of agricultural emissions. Livestock numbers are largely driven by growth in export and domestic demand, the ability of the land to support these livestock numbers in the continuing drought and a general shift in both domestic and international consumer preferences towards meat products.
Land use, land use change and forestry (LULUCF)—The forestry sub-sector covers commercial forestry operations and environmental tree planting in Australia, and prescribed burning of forest and wildfires. Emissions from land use change are the result of the burning of removed forest cover, the decay of unburnt vegetation, and emissions from soil disturbed in the process of land clearing. This is offset to some extent by carbon sequestration due to regrowth of vegetation on previously cleared land. Estimates of emissions from land use change depend on the area of forest cover removal and the method of forest conversion and land development. They rely on estimates of the amount of carbon sequestered in biomass and soils, which differ by vegetation type, geography and climate. Recent rates of forest cover removal have varied according to seasonal conditions (particularly rainfall), vegetation management regulation and commodity prices.
LULUCF activities involve both emissions and removals (or 'SINKS'). The United Nations Framework Convention on Climate Change (UNFCCC) defines 'sink' as 'any process, activity or mechanism which removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere'. In the calculation of greenhouse gas flows, LULUCF is a controversial subject. The UNFCCC includes all emissions from the human use of land under LULUCF, however the Kyoto Protocol emissions from LULUCF in the 2008–2012 commitment period are limited to new forest plantings since 1990 (afforestation and reforestation) and the deliberate, human induced deforestation on land that was forest on 1 January 1990
—The waste sector includes emissions from solid waste disposed to landfill and from the treatment of domestic, commercial and industrial wastewater. The primary greenhouse gas emitted is methane. Emissions from solid waste disposal account for over 70 per cent of waste emissions. Small amounts of carbon dioxide are generated by the incineration of wastes containing fossil fuels or solvents; waste incineration is a relatively minor source of greenhouse gas emissions. The other important greenhouse gas, nitrous oxide, is released from the treatment of human sewage but it too is a relatively minor source of emissions from waste. The key drivers for emissions growth in the waste sector are population growth, the growth in annual waste produced per capita and the type of landfill or wastewater treatment facility where the waste streams are deposited or processed.
15 November, 2010