What causes global warming?
Where does greenhouse gas pollution come from?
Burning of fossil fuels
Most of Australia's greenhouse gas emissions come from the burning of fossil fuels for energy (eg. for electricity and transport). When oil, gas or coal burns, carbon contained within it combines with oxygen in the air to create carbon dioxide.
Deforestation: burning and removing vegetation
Plants take up carbon dioxide from the air during photosynthesis and are therefore often referred to as carbon 'sinks'. When land is cleared and vegetation removed or burnt, the stored carbon is converted back to carbon dioxide.
Since 1788, we have cleared 20 billion trees and significantly modified more than 70% of Australia's native vegetation.
Farming
Animals, particularly sheep and cattle, produce large amounts of methane. Some fertilisers also release nitrous oxide, which is another greenhouse gas.
Waste breakdown
Carbon dioxide and methane is released during the decay of food, vegetation and paper dumped in landfills. The same thing occurs when sewage wastes break down.
Industry
Many industrial processes such as cement and liquid natural gas production and coal mining produce or emit a variety of greenhouse gases.
Where do Australia's greenhouse gases come from?
Australians are the highest per-person greenhouse gas polluters in the developed world.
The main sources of Australia's greenhouse gas emissions are :
- 50% from stationary energy, primarily electricity generation;
- 16% from agriculture, mostly from cattle and fertilisers;
- 14% from transport;
- 6% from land use changes, and
- 5% from industrial processes such as cement and aluminium production
Across the economy:
- 20% of Australia's emissions are indirectly (and in the case of transport – directly) attributable to households;
- 10% to offices, restaurants, hotels and the commercial sector generally, primarily from building energy use;
- 15% to aluminium production and other forms of energy-intensive manufacturing; and
- 30% from mining, LPG production and less energy-intensive forms of manufacturing.
Australia's electricity-related emissions are so high because we rely primarily on coal for electricity generation and coal is the most greenhouse-intensive fuel. Australia's 28 coal-powered stations produce over 97% of our emissions, which is more than the entire emissions of many countries.*
Australia's emissions are increasing
Australian emissions have substantially increased since 1990, with:
- Electricity, gas and water emissions increasing by 46.9%;
- Mining emissions by 44.8%;
- Residential emissions increasing by 28.6%;
- Services, construction and transport emissions increasing by 23.7%; and
- Manufacturing emissions by 2.9%.
Australia is a wealthy country and can afford to reduce its emissions now that solutions are available.
* Argentina, Belgium, Greece, Ireland, Israel, Malaysia, Pakistan, Portugal, Sweden, Switzerland, Thailand, Turkey, all eastern European countries apart from Russia and Poland, and all African countries apart from South Africa
