GREENHOUSE GAS EMISSIONS AND CLIMATE CHANGE
GREENHOUSE GAS EMISSIONS - A GLOBAL PROBLEM
Greenhouse gases (GHG) are a natural part of the Earth's atmosphere, acting to absorb and re-radiate the sun's heat and so maintain the Earth's surface temperature at a level which supports life. GHG include carbon dioxide (CO2 ), methane, nitrous oxide, perflurocarbons, hydrofluorocarbons, and sulphur hexafluoride. For purposes of measurement, the emissions of these different gases are aggregated and converted to carbon dioxide equivalents (CO2-e).
GHG emissions from human actions are contributing to a warming of the Earth's surface and climate change by increasing the concentrations of the gases that trap heat, resulting in an enhanced greenhouse effect and higher Earth surface temperatures. These actions include the burning of fossil fuels (coal, oil and natural gas), agriculture and land clearing.
Global average surface temperatures have increased by approximately 0.6 degrees Celsius over the last 100 years. Climate change effects include increased heatwaves, warming of the deep oceans, melting of glaciers, rising ocean levels and an increased incidence of floods and droughts in some regions. Human activities are estimated to have increased atmospheric concentrations of CO2 by more than a third, nitrous oxide levels by about 17% and methane levels have doubled.
Recognising climate change as a global problem, the 1997 United Nations Framework Convention on Climate Change (UNFCCC) initiated the Kyoto Protocol, an international treaty designed to limit global GHG emissions. The Kyoto Protocol, which came into effect in February 2005, requires signatory countries to meet mandated targets for emission reductions. Although Australia is not a signatory to the Protocol, the Australian Government has committed to limiting GHG emissions to the internationally agreed target of 108% of 1990 levels between 2008 and 2012.
To give effect to its Kyoto commitment, the Australian Government initiated broad ranging measures through the Safeguarding the Future: Australia's Response to Climate Change (1997) and the National Greenhouse Response Strategy (1998). Overall, Australia appears on track to meet its internationally agreed Kyoto target with national GHG emissions increasing by only 2.3% from 551.9 mill. tonnes of CO2-e to 564.7 mill. tonnes CO2-e over the period 1990-2004. (More information can be obtained from the web site <http://www.greenhouse.gov.au>.)
As a further climate change initiative, the Australian Government announced, in January 2006, its membership of the Asia-Pacific Partnership on Clean Development. The Partnership, which includes China, India, the Republic of (South) Korea and the USA, will promote voluntary joint business and government investment ventures with the aim of delivering sustained economic growth and lower GHG emissions. Since 1997, Australia has invested $1.8b to address climate change, including $500 million (m) for low emissions technologies and over $200m for renewable energy initiatives. Over the period 2006-2011 a further $100m, including $25m for renewable energy projects, will be invested under the Partnership.
In 2004, Australia's total net GHG emissions, using Kyoto accounting provisions, were 564.7 mill. tonnes of CO2-e. Graph 24.18 shows that CO2 accounted for 415.0 mill. tonnes of CO2-e, or 73.5% of Australia's total net emissions, methane for 119.7 mill. tonnes of CO2-e (21.2%), nitrous oxide for 24.8 mill. tonnes of CO2-e (4.3%) and the other gases made up 5.2 mill. tonnes of CO2-e (1.0%) of total emissions.
Graph 24.19 shows the contribution to total net GHG emissions by sector in 2004. The major source of emissions was the energy sector (including stationary energy, transport and fugitive emissions from fuels) which accounted for 387.2 mill. tonnes of CO2-e (68.6%) of total national emissions in 2004. The agriculture sector contributed a further 93.1 mill. tonnes of CO2-e (16.5%), land use, land use change and forestry 35.5 mill. tonnes of CO2-e (6.3%), industrial processes 29.8 mill. tonnes of CO2-e (5.3%) and waste 19.1 mill. tonnes of CO2-e or 3.3% of total national emissions.
Table 24.20 provides details of the change in GHG emissions on a sectoral basis over the period 1990-2004. Emissions from the energy sector (including electricity generation) increased by 34.7% from 287.5 mill. tonnes CO2-e in 1990 to 387.2 mill. tonnes CO2-e in 2004. While emissions from the agricultural, industrial processing and waste sectors remained relatively constant over this period, emissions from the land use, land use change and forestry sector declined from 128.9 mill. tonnes CO2-e in 1990 to 35.5 mill. tonnes CO2-e in 2004. This decline reflects the greenhouse sink offset resulting from the afforestation and reforestation in the forestry subsector.
When combined, New South Wales (158.7 mill. tonnes of CO2-e), Queensland (158.5 mill. tonnes of CO2-e) and Victoria (123.0 mill. tonnes of CO2-e) accounted for over 78% of total GHG emissions in 2004. Total emissions from Western Australia were 68.5 mill. tonnes of CO2-e, South Australia 27.6 mill. tonnes of CO2-e, Northern Territory 15.6 mill. tonnes of CO2-e, Tasmania 10.7 mill. tonnes of CO2-e and the ACT 1.2 mill. tonnes of CO2-e.
While Australia only accounts for around 1.4% of global GHG emissions, its CO2 emissions per person are relatively high compared with other OECD countries. In 2003, 17.4 tonnes of CO2 were emitted for every Australian compared with an OECD country average of 11.1 tonnes of CO2 per person (graph 24.21). Australia's relatively large emissions per person can be attributed to factors such as the high usage of coal in electricity generation, the energy intensive aluminium smelting sector, and the high dependence on motor vehicles and trucks for transport.
Graph 24.22 shows that, in 2003, the emissions intensity of the Australian economy (0.81 kg CO2 per dollar of GDP) was relatively high compared with the OECD average (0.48 kg CO2 per dollar of GDP). However, Australia's emissions intensity declined by 35% over the period 1990-2004 from 1.1 to 0.7 kg CO2 per dollar of GDP. This trend reflects factors such as the large decline in emissions from agriculture and forestry, structural changes in the Australian economy with a shift away from energy intensive manufacturing to the services sector, and the impact of emissions management across the sectors.
24.20 GREENHOUSE GAS EMISSIONS(a)
Change from 1990 to 2004
|Fuel combustion (sector approach)|
|Manufacturing industries and construction|
|Fugitive emissions from fuels|
|Oil and natural gas|
|Land-use change and forestry|
|(a) Carbon dioxide equivalent emissions|
Note: Totals may not be additive due to rounding.
|Source: Australian Greenhouse Office, 'National Greenhouse Gas Inventory 2004'.|
This page last updated 16 January 2008