Keep Winter Cool - Australia

Creating a Carbon Footprint and Going 'Carbon Neutral'

'Carbon Neutral' is a term given to a person or an activity that does not contribute to global warming. For instance, walking to school is carbon neutral as no greenhouse gases are produced, and greenhouse gases cause global warming. But you can also be carbon neutral and generate greenhouse gases if you remove greenhouse gases somewhere else. For instance, you could catch the bus, which generates greenhouse gases (as the bus burns fossil fuel to run), and then plant a tree (which consumes the greenhouse gas carbon dioxide) to absorb these greenhouse gases, thus making your net greenhouse gas emissions zero. So, if you catch the bus and then plant a tree, you are also being 'carbon neutral'.

Greenhouse gases are a natural part of the atmosphere. They absorb and re-radiate the sun's warmth maintaining the Earth's surface temperature at levels in which we can survive. Without greenhouse gases the surface of the earth would be so cold that life as we know it would not exist. There are six main greenhouse gases. Some occur naturally: carbon dioxide, methane, nitrous oxide; and some are man-made: hydrofluorocarbons, perfluorocarbons and sulphur hexafluoride.

Scientists have shown that concentration of greenhouse gases in our atmosphere is currently much higher than what occurs naturally and consider that this is because of human activities, particularly the burning of fossil fuels (coal, oil and natural gas), and, to a lessor extent, agriculture and land clearing.

Every time we turn on the light at home, drive to the movies or watch TV we are consuming energy. If that energy is suppled from fossil fuels such as coal (which is where most of Victoria's electricity comes from), petrol, gas or diesel, then this activity is producing greenhouse gases. If the energy is supplied from renewable sources such as wind, hydro or solar, then the activity is not producing greenhouse gases. Greenhouse gases are also produced at the rubbish tip (also known as a landfill). As your rubbish decomposes, it produces methane - a greenhouse gas - which is released to the atmosphere.

Even though there are many types of greenhouse gases, for ease of reporting, all greenhouse gases are measured as carbon dioxide equivalents (CO₂). This is the amount of carbon dioxide (CO₂) that would be required to cause the equivalent amount of global warming from all of the greenhouse gas produced from a particular activity.

To assist people calculate their greenhouse gas emissions (in CO₂), the Australian Greenhouse Office has developed 'emission factors' for each greenhouse gas generating activity. For example, petrol has an emission factor of 2.8kg of CO₂ per 1 litre of petrol. This means that when a car consumes 1 litre of petrol, it will be producing a range of greenhouse gases, equivalent to the global warming potential of 2.8kg of CO₂. These emission factors have been used to create the Keep Winter Cool carbon calculator.

Being energy efficient and using renewable energy will reduce the greenhouse gas emissions of your activities; however, you will find that there will some activities which generate emissions that are unavoidable. You can neutralise the global warming effect of these unavoidable emissions through "offsets". If you offset all the emissions of your activities, then you have become 'carbon neutral'.

While some activities generate greenhouse gases, offsets are other things or activities that absorb and store greenhouse gases. The most common offsets are trees. By planting trees enough trees to offset your greenhouse gas emissions, you are neutralising the global warming potential of your activity and consequently achieving 'carbon neutral' status. You can also obtain offsets through reducing energy consumption somewhere else, such as by installing energy efficient light globes at home or at school. It is important that offsets are obtained through an accredited program. These programs charge per tonne of greenhouse gas to be offset. So the less residual greenhouse gas emissions you produce, the cheaper it will be to become carbon neutral.