Decoding your carbon footprint

As you know, our actions have an impact on the environment. We produce greenhouse gases directly, and indirectly, throughout our everyday lives.

Greenhouse gases (GHGs) are called that because they create the ‘greenhouse effect.’

That’s a natural phenomenon that insulates the Earth from the cold of space. 🥶 Good, right? Not exactly.

As the heat from the sun (solar radiation) is absorbed and then re-emitted from the earth’s surface as infrared energy, the greenhouse gases prevent some of that heat from leaving the earth’s atmosphere. Their ability to do that varies depending on their molecular structure, how long they tend to stay in the atmosphere for, and a whole bunch of other scientific stuff 👩‍🔬

There are 10 main GHGs; of these, water vapor (H2O), carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) are naturally occurring…. But Perfluorocarbons (CF6, C2F6), hydroflurocarbons (CHF3, CF3CH2F, CH3CHF2), and sulfur hexafluoride (SF6) are only present in the atmosphere thanks to our industrial processes.

Humans’ interference (burning all those nasty fossil fuels) has messed up the energy balance between incoming solar radiation and the heat released back into space, which has increased the greenhouse effect and caused the climate emergency. Well done humans.

A carbon footprint measures our total GHG emissions, helping us to determine how much damage we’re doing to the planet.

Carbon is a chemical element that exists in many gases and compounds - carbon mixes with oxygen which creates carbon dioxide and carbon mixed with hydrogen produces methane. When we’re talking about global warming, the word ‘carbon’ is often used to talk about all greenhouse gases, and it is also often used when people are actually referring to carbon dioxide. 

Our carbon footprints are not just made up of carbon dioxide. They’re made up of all sorts of GHGs. 

Every product we use will produce all sorts of greenhouse gases. Their differing ability to trap heat in the atmosphere means they’ll have a differing global warming potential (GWP). The GWP of a GHG indicates the amount of warming a gas causes over a given period of time (normally 100 years).

GWP is an index, with CO2 having the index value of 1, and the GWP for all other GHGs is the number of times more warming they cause compared to CO2. E.g. 1kg of methane causes 25 times more warming over a 100 year period compared to 1kg of CO2, and so methane has a GWP of 25. 

Our carbon footprints are measured in units of mass of carbon dioxide equivalents (CO2e) so that we can combine all the different gases and their GWPs together in one measurement. 

To work out a CO2e, we multiply the amount of GHG by its GWP. E.g. if 1kg of methane is emitted, this can be expressed as 25kg of CO2e (1kg methane x 25 = 25kg CO2e).

Even though it’s very common now to see CO2e measurements, we will still see terms such as ‘carbon accounting’ or ‘low carbon economy’ thrown around, when really they mean ‘greenhouse gas accounting’ or ‘low greenhouse gas economy’. 

Find out what your carbon footprint is 👇

There are loads of questionnaires available that can help you work out your carbon footprint. We recommend the WWF one, which you can find here. It’ll ask you a couple of questions about your lifestyle (be honest!) and then it’ll tell you your carbon footprint and how it compares to the average UK and world footprints.

The 2022 UK emission target is currently 10.5 tonnes of CO2e, assuming the UK per capita footprint follows the same trajectory as the UK Climate Change Committee's Balanced Net Zero Pathway.

This is a huge target - but we believe that every single one of us can choose to make a difference. Let’s do this!