"The Kyoto Protocol is an agreement under which industrialized countries will reduce their collective emissions of greenhouse gases by 5.2% compared to the year 1990 (but note that, compared to the emissions levels that would be expected by 2010 without the Protocol, this limitation represents a 29% cut). The goal is to lower overall emissions of six greenhouse gases - carbon dioxide, methane, nitrous oxide, sulfur hexafluoride, hydrofluorocarbons, and perfluorocarbons - averaged over the period of 2008-2012. National limitations range from 8% reductions for the European Union and some others to 7% for the US, 6% for Japan, 0% for Russia, and permitted increases of 8% for Australia and 10% for Iceland.[13]
There is a range of gases that contribute to the enhanced greenhouse effect. The impacts of these gases vary and so, for simplicity, the emissions effect of each gas is converted to equivalent kilograms of CO2 (CO2-e).
The range of greenhouse gases include:
carbon dioxide (CO2)
methane (CH4)
nitrous oxide (N2O)
hydrofluorocarbons (HFCs)
perfluorocarbons (PFCs)
sulphur hexafluoride (SF6)
The table below breaks down the type and source of the most significant gases that contribute to the enhanced greenhouse effect; their global warming potential; and the types of activities that produce greenhouse gas emissions.
Types and sources of significant greenhouse gases:
|
Greenhouse gas |
Source |
Global warming potential* |
Activities that contribute |
|
Carbon dioxide (CO2) |
Burning of fossil fuels and land-clearing |
1 tonne = 1.0 t CO2-e |
Electricity generation and use; transport |
|
Methane (CH4) |
Agricultural activities; emissions from landfills and wastewater treatment; emissions from fossil fuel production and mining |
1 tonne = 21 t CO2-e |
Resource consumption; primary production; waste disposal to landfill |
|
Nitrous oxide (N2O) |
Burning of fossil fuels and vegetation |
1 tonne = 310 t CO2-e |
Industrial processes; electricity generation and consumption; transport |
|
Hydrofluorocarbons (HFCs) |
Used in refrigeration and air conditioning |
1 tonne = 3000 to 5000 t CO2-e |
Industrial processes; building design; refrigeration |
|
Perfluorocarbons (PFCs) |
Emitted during aluminium production,
Burning PTFE nonstick cookware. |
1 tonne = 6500 to 9200 t CO2-e |
Manufacturing; resource consumption |
|
Sulfur hexafluoride (SF6) |
Electricity transmission and distribution |
1 tonne = 23 900 t CO2-e |
Electricity generation and consumption |
|
* Note: Each greenhouse gas varies in its effect of trapping the sun's heat. The extent of this variation is expressed in terms of its 'global warming potential' (GWP) relative to CO2. GWP's provide a means of combining the emissions of several greenhouse gases from a particular activity to calculate a total emission figure expressed in terms of CO2 equivalence. For example, if emissions from a particular activity were 100 tonnes of CO2 and 1 tonne of methane, the total CO2 emissions would be 121 tonnes, i.e. (100 t x 1) + (1 t x 21 CO2-e) = 121 t CO2-e. Source: Victoria's greenhouse gas emissions, 1990-95: Cross-sectoral analysis, Wilkenfeld,1998. |
