The gradual warming of the atmosphere due to an increase in heat-trapping gases. These gases, including a carbon dioxide equivalent (or CO2-e) and methane, are known as greenhouse gases.
Carbon offset
The reduction of greenhouse gas emissions from one activity or project to compensate for the emissions of another activity or project. Offset projects include:
schemes that remove greenhouse gases from the atmosphere—for example, tree planting (since trees capture and store carbon)
measures that reduce greenhouse gases from entering the atmosphere in the first place (such as using light bulbs that improve energy efficiency).
A claim that carbon has been offset does not automatically mean something is carbon neutral, if only part of the overall greenhouse gases produced by that product, service, or activity has been countered.
Carbon credits
The units by which carbon offsets are measured. One tonne of CO2-e should be equivalent to one carbon credit.
Carbon footprint
The total amount of carbon dioxide and other greenhouse gas emissions associated with a person, product, service, or activity is often called its carbon footprint.
Carbon footprints are measured using different footprint calculators which take into account different factors.
The most credible footprint calculators should take into account indirect, as well as direct emissions. Indirect emissions may include those produced during the manufacturing and disposal of a product, as well as those created over its life. In the case of companies or individuals, indirect emissions might be those associated with air travel and office waste.
Carbon neutral
Carbon neutral commonly means that the net emissions associated with a product or activity are zero. However, because different methods of calculating overall emissions may take into account different factors, the claim can mean different things.
For instance, one business might claim to be ‘carbon neutral’ because it has offset the emissions directly associated with its operation, such as electricity use, as well as indirect emissions from air travel and office waste, for example.
Another business might make the claim of carbon neutrality based only on offsetting its electricity use.
Alternatively, a business might claim a product is carbon neutral, because it has offset the emissions associated with its production, but not the emissions it will produce over its lifetime.
Because there is no set definition of what is carbon neutral, it can be difficult to assess claims of carbon neutrality on face value. However, businesses that clearly explain how and what has been offset, or that purchase offsets that are independently verified by a credible standard or certification (see other certification schemes), are most likely to be reliable. If no information is provided to support a claim, don’t rely on it.
