Carbon footprint definition – the 6 most important aspects explained
Calculate a footprint for your university or any other organisation using conversion factors. Read on to learn how to decide what you want to include and how to track changes.
Understand the carbon footprint definition
Carbon footprint definition – the overall footprint: The carbon footprint of your university or other organisation is the sum of all greenhouse gas emissions induced from activities of the institution, as measured in CO2 equivalents.
Calculating this footprint allows you to:
- Better understand how your university contributes to climate change,
- Identify where emissions are created,
- And understand which areas you need to address to reduce emissions.
You can develop a stand-alone CO2e footprint or do so as part of an overall sustainability assessment. You can publish the result as an infograph, presentation, poster or as part of a sustainability report
Measure your footprint in CO2 equivalents
Climate change is caused by various greenhouse gases, such as:
- Carbon dioxide (CO2)
- Water vapour (H2O)
- Nitrous oxide (N2O)
So why is the carbon footprint definition all about CO2?
Since the impact of each greenhouse gas differs, their total impacts need to be measured in a common way. For example, one tonne of methane is far more harmful to the climate than one tonne of CO2.
To make the calculation and communication easier, all greenhouse gases are measured in CO2 equivalents (often also shortened as “CO2e”). The number represents how much pure CO2 would have the same impact on the climate, as the mix of gases that was actually emitted.
Carbon footprint definition – CO2 equivalent: CO2e (carbon dioxide equivalent) expresses the impact of each different greenhouse gas in terms of the amount of CO2 that would create the same amount of warming.
Use conversion factors for your calculation
To calculate the footprint of your organisation, you can use conversion factors. These allow you to convert consumption and activities that contribute to climate change into CO2 equivalents.
In this way, you can calculate the climate impact of, for example, driving 100 kilometres in an average passenger car or flying from Berlin to Lisbon.
For example, for electricity consumption, you can find out the specific conversion factor of your electricity company. They will often publish the conversion factor. If they don’t, you can send them a request. Alternatively, you can use average values published by organisations like DEFRA (UK) or CO2 emissiefactoren (Netherlands).
Make sure you always cite the source of the factors, so that readers can understand how you reached your conclusions. You can also find a simple calculation tool in the University Sustainability Assessment Framework.
Include scope I, II or III emissions
Carbon footprint definition – the scopes: A carbon footprint is usually divided into three scopes:
Scope I are all emissions that your organisation emits itself. For example, if your university has a gas powerplant, those emissions would be counted as scope I emissions.
Scope II are emissions that are emitted by an electricity provider, as a result of your university’s electricity consumption.
Scope III are emissions that are indirectly caused by your organisation (other than electricity consumption). For example, the emissions emitted in supply chains or travel behaviour are counted as scope III emissions.
Scopes I and II are narrowly defined to avoid them being counted by more than one organisation. You can easily calculate them and compare them from year to year. If you also want to calculate a scope III footprint, make sure that you clearly define what is included and only compare values that were calculated in the same way.
For an in-depth carbon footprint definition based on these scopes, you can take a look at the Greenhouse Gas Protocol.
Calculate relative footprints as well
The total CO2e footprint of your university is an important indicator and you should always publish it.
However, relative footprints can also be a useful addition. For example, you could break down the total emissions into:
- Emissions per square metre;
- Emissions per building;
- Per capita (per person) emissions.
Tip: Make sure to triple check your math when you calculate relative footprints. A common mistake is to add or subtract per capita numbers (for example from different scopes), which will give you an incorrect result.
Don’t account for carbon offsetting!
Carbon offsetting is the concept of compensating your organisation’s CO2e emissions, by reducing emissions somewhere else; for example, by investing money into energy efficiency, reforestation or other emission reduction projects.
Many universities offset carbon emissions related to electricity use, heating, flights or commuting. Can your organisation then subtract the emissions it offsets from its total carbon footprint? The simple answer to that question is no.
Reporting standards such as GRI G4 require you to state the footprint independent of any emissions trading or offsetting. Of course, you can mention that the university is offsetting emissions and how. However, you should always publish the original footprint as well, without any offsetting.
Photos by Ian Britton and jonbgem.