What do carbon footprints measure?

The idea of a carbon footprint is becoming more popular as a way of measuring the effect products and activities have on climate change. Carbon footprints are a proven and scientifically valid method to calculate CO2 emissions.

A carbon calculator uses known carbon dioxide emissions for a specific unit of activity or product such as energy use, food consumption, transport or waste disposal. This is combined with information about how much a person does this activity or how many of a product is purchased to give a carbon footprint, usually expressed as kilogram of CO2 per person per year.

You may have seen or used online carbon footprint calculators to assess your individual carbon emissions for travel or the energy used by your home. Hardly a week goes by without the media reporting the carbon emissions of particular products. The average annual carbon footprint for a person in the UK is around 12000 kg (or 12 tons).

How does the carbon footprint calculator work?

The carbon footprint calculator works by measuring components of the five DCSF Sustainable School Doorways in your school responsible for CO2 emissions. Data about these Doorways is collected and entered onto the website and a school carbon footprint is calculated. On the website the Doorways are referred to as Assignments.

Some of the assignments are for individuals and some are for the Carbon Detectives Team. The Carbon Detectives Team should work closely with you and other members of staff to calculate the carbon footprint of the school and plan action.

The six assignments for the Carbon Detectives Team are:

  • Energy and water - pupils discover how much water, electricity, gas and other energy the school uses in a year.
  • Food - pupils find out about the food eaten in the school including school meals, packed lunches and snacks, plus drinks.
  • Waste and recycling - pupils measure certain items of waste and how it is disposed.
  • Travel - pupils investigate how people travel to and from school and the trips the school makes.
  • Purchasing - pupils find out how much paper is used, and how many of certain items of equipment the school has and purchases each year.
  • Buildings and grounds - pupils find out about the area of the school and the number of new trees planted each year.

The calculator uses the data entered for each assignment and applies a carbon conversion factor to produce a CO2 result in kilograms. Carbon conversion factors provide information about the amount of carbon produced by an activity. For example, a large car produces 0.10 kg CO2 per passenger km, whereas a bus produces 0.05 kg CO2 per passenger km. Using this information the total CO2 emissions for travel in a school are calculated. Data for each of the assignments is processed in a similar way.

How is the website structured?

The website starts with a short animation which highlights for Key Stage 2 and 3 pupils the environmental state of the planet and the fact that schools contribute to climate change through their carbon emissions.

The animation aims to stimulate your pupils to use the Carbon Detectives’ Kit to find out the carbon footprint of their school and work towards reducing it. Ideally they would be in charge of as much of the data collection and decision-making as possible but help from you and other staff in the school will be vital.

To start the process of exploring and measuring CO2, you will need to Register your school. This simple process gives each school a unique homepage. This is the main reference point for the footprint calculation process. Some pages on the site can be viewed without registration, but registration is required before data can be entered.

The Explore and measure section explains how to collect the information required and includes downloadable Guidelines for pupils. You will also find information about how the calculations work.

The Results pages display the results as an overall school carbon footprint and per person carbon footprint. The results are also displayed for each assignment so that your pupils can see which activities contribute most to the overall footprint.

The school results will tell you a lot about the school and its CO2 emissions.

In the Take action section the pupils are encouraged to analyse their results and ask critical questions such as:

  • What is the overall impact of our school on climate change? How does this compare with other schools?
  • Which areas of activity contribute most to the carbon footprint?
  • What improvements can be made and which can be made for least effort?
  • Which activities in the school are not worth changing now?
  • How do we prioritise action?

Tips and ideas are provided for the pupils to consider.

A simple Lab lets pupils plan actions and see their effect on the school’s carbon footprint. Pupils can choose seven actions and investigate whether they have a big or small impact on the school carbon footprint. They can also explore the different impacts of combined individual actions and whole school change. Finally, the carbon pledge helps pupils finalise and publicise their action plan.

The Carbon Detectives’ Kit is not a one-year project. The Carbon Detectives Team and pupils are encouraged to set targets and regularly return to measure the schools CO2 emissions as often as they like to see how the school is progressing. The calculator stores school data so pupils can compare year on year improvements.

Important information about how the site works

Parts of the website are secure, but some areas are not.

To start collecting data and entering it into the site, a school has to be registered. This involves entering the school’s DCSF number and creating a username and password.

Once this is done the name of the school will be highlighted on the database, and data can be entered by anyone clicking on the school name. To enter data does not require the password because all pupils need easy access to the calculator to enter their personal travel and food information. There is a risk in having such an open site. It means for example that pupils can potentially enter false data into their school pages or even pages of another school. However, in the interests of getting pupils involved and making the site easy to use, it is a risk that has been taken.

To minimise possible problems, it is suggested that you don’t tell your pupils of the ability to enter false data as this will draw attention to the opportunity. It is also suggested that the data collection process takes place over a set period of time and does not take too long. You may want to get the Carbon Detectives Team to keep an eye on the data and investigate any unlikely or surprising amounts.

Carbon conversion factors

The website uses carbon conversion factors to convert raw data (e.g. number of miles travelled to school) into carbon emissions measured in tonnes. The carbon conversion factors are supplied by Defra and Best Foot Forward. Carbon footprints is a developing science and to keep up with the latest changes the carbon conversion factors used in this site may change.