Global warming and greenhouse gases

New Gen Coal

Global warming and greenhouse gases

 

Greenhouse gases and the atmosphere

Greenhouse gases make up less than 1% of our atmosphere but have a big impact on the temperature of the earth, trapping the sun’s heat in a natural process known as the greenhouse effect.

 
 

What greenhouse gases are associated with human activities?

Many greenhouse gases are naturally occurring, and include water vapour (H2O), Carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Human activities are increasing the concentrations of these gases in our atmosphere, enhancing the greenhouse effect and causing a rise in the average temperature of the earth. This process is known as ‘global warming’.

Carbon dioxide

The most significant anthropogenic greenhouse gas is CO2, representing up to 77% of total greenhouse gas emissions1. The concentration of CO2 was stable at 260-280 parts per million (ppm) for the past 10,000 years, but levels have risen dramatically since the industrial revolution to an unprecedented 379ppm2. The additional CO2 in our atmosphere is emitted from a variety of sources, including the burning of fossil fuels and intensive agriculture.

Methane

Methane is emitted in much lower concentrations than CO2 but is 21 times more effective at trapping the sun’s heat. Concentrations have more than doubled since pre-industrial levels reaching 1774 parts per billion (ppb)3, primarily from agriculture (60%), fugitive emissions from fossil fuels (25%) and waste disposal (13%)4.

Nitrous oxide

Reaching a concentration of 329ppb in 2005, levels of this greenhouse gas have increased by 18% since pre-industrial times5. The rising concentration of N2O in our atmosphere is primarily the result of intensive agriculture, which accounts for 84% of emissions. Once emitted, this gas remains in the atmosphere for around 114 years.

Share of different sectors in total global anthropogenic greenhouse gas emissions (2004)1

Global Anthropogenic GHG Emissions

Australia’s greenhouse gas emissions

The Intergovernmental Panel on Climate Change (IPCC) estimates that Australia produces 1.5% of the world’s greenhouse gas emissions, 74.3% of which is CO2. The primary sources of these emissions are electricity generation (34.4%), transport (13.7%) and agriculture (15.6%)6. The Australian government has committed to reduce Australia’s GHG emissions by 60% by 20507.

Learn more about the Australian Government's commitments.

Why should we reduce our greenhouse gas emissions?

According to the IPCC, average temperatures on earth have increased by 0.74°C over the past 100 years8. Most scientists agree that this global warming is the result of increasing concentrations of anthropogenic greenhouse gases. This is why the Australian Coal Association (ACA) is investing over $1 billion through the COAL21FUND into developing technologies to capture and safely store the CO2 produced from coal fired power stations, reducing greenhouse gas emissions and the effects of global warming.

Learn more about carbon capture and storage technology.

  1. 1 IPCC Climate Change 2007 Assessment report 4: Synthesis report p36
  2. 2 IPCC Climate Change 2007 Assessment report 4: WG1 Technical summary p27
  3. 3 IPCC 2007 Assessment report 4 WG1: FAQs "Are the increases in Atmospheric Caron dioxide and other greenhouse gases during the industrial era caused by Human activities?" p115
  4. 4 Australian department of climate change 2008
  5. 5 IPCC Climate Change 2007 AR4 WG1 Technical summary p27
  6. 6 Australian government department of climate change - Australia's National greenhouse inventory 2006 (released 2008)
  7. 7 Australian government department of climate change – "Australian government action on climate change" 
  8. 8 IPCC Climate Change 2007 Assessment report 4 WGI report: FAQs – How are temperatures changing on earth?
 
 

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