Frequently Asked Questions

What is a carbon footprint?

A carbon footprint is the amount of greenhouse gas released when an activity happens. That activity usually boils down to fossil fuel burning, or, refrigerant gas loss.

A couple of examples - It could be that you have driven your petrol car, thereby causing petrol to be burnt, and carbon dioxide to be released into the atmosphere.

Or, you had your air conditioning in your car topped up – this means that some refrigerant gas has leaked into the atmosphere and has to be replaced.

What is a greenhouse gas?

A greenhouse gas is a gas which traps heat, a bit like a greenhouse.

When the sun shines and warms up our atmosphere, greenhouse gases present in our atmosphere absorb that heat. More heat becomes trapped in our atmosphere, rather than radiated back in to space. Therefore, our atmosphere heats up, and this causes a change in our climate.

How are greenhouse gases included in a carbon footprint?

Seven greenhouse gases come under the umbrella of a carbon footprint

These gases are carbon dioxide, methane, nitrous oxide, sulphur hexafluoride, nitrogen trifluoride, sulphur hexafluoride, hydrofluorocarbons (HFC) and perfluorocarbons (PFC)

HFCs and PFCs are families of refrigerant gases and are related to air conditioning, and refrigeration.

The other five are gases in their own right – CO2, CH4 and N2O are common in the burning of fossil fuels e.g. petrol, diesel, aviation fuel.

SF6 is used in the electrical transmission grid as an insulator in high voltage equipment. It’s usage is increasing as more electrical generation such as large wind turbines are added to the grid. https://www.bbc.com/news/science-environment-49567197

NF3 is used in hi-tech industries including the manufacture of electronic goods. The following link from the World Resources Institute explains about this gas, the most recent addition to the carbon footprint calculation methodology. https://www.wri.org/blog/2013/05/nitrogen-trifluoride-now-required-ghg-protocol-greenhouse-gas-emissions-inventories

How is a carbon footprint measured and calculated?

A carbon footprint is calculated using a precise methodology.

This is either the Greenhouse Gas Protocol, or ISO14064. These are very similar and are the best and most comprehensive ways of calculating carbon footprints.

You can see the greenhouse gas protocol here. https://ghgprotocol.org/corporate-standard