Getting the measure of things
“What will it cost?” It’s a question we’re all too familiar with when it comes to managing our personal finances or balancing the budgets of our community organisation – but what about the environmental costs of our actions?
In his book Carbon Detox, George Marshall makes the case that climate change is one area where we can measure precisely what the cost is in environmental terms. This is because, at least in theory, it’s possible to measure our carbon emissions right down to the last gram. This month we’ll look at a number of different ways you can measure the environmental impact of your community. But first, why measure at all?
why is measuring important?
Not everyone finds measuring carbon footprints fascinating for its own sake (did you know a packet of Walkers crisps have a carbon footprint of 75g[1], fancy that!). But there are practical reasons for wanting to know the environmental cost.
Firstly, by measuring our impact, it allows us to compare the impact of different choices. By knowing the carbon footprint of a packet of crisps, compared with say the 235g for a large cappuccino, I can make a more informed choice when deciding on my mid-morning treat. Secondly, it gives us a baseline against which to measure our progress over time. Walkers crisps used to have a per pack footprint of 85g, but by understanding the contribution different parts of the manufacturing process had on its overall footprint, the company was able to make informed decisions about reducing the product’s carbon footprint. Although a saving of 10g per packet might seem negligible, with around 10 million packets of Walkers crisps manufactured each day – that adds up to a daily saving of 10 tonnes (The Guardian).
what is a carbon footprint?
For households, a carbon footprint is a measure of the annual contribution to the greenhouse gases that are driving global climate change. How you power your home, the food you eat, the transport you use, and the things that you buy – these all contribute to your carbon footprint.
One slightly confusing thing is that no one seems to be able to agree what the “average” carbon footprint is for the UK, with estimates varying between 10 and 15 tonnes. This is because of the different methodologies used to calculate them. For example, one way of calculating the per capita footprint is to take the UK’s overall carbon footprint and divide it equally between the 62 million or so UK residents. But, the figure varies depending on whether you take into account the footprint of imported and exported goods.
So, where you draw the boundary of what’s included in your footprint makes a big difference. This is also the case when it comes to calculating household footprints from the bottom up. For example, the Quicksilver calculator is likely to give you a larger carbon footprint than the Act On CO2 calculator as Quicksilver includes an estimate for your household’s consumption of goods and services.
Different calculators can also give you different results because of differing methodologies and what they measure. For example a calculator that calculated the carbon footprint of a flight based purely on CO2 emitted during the flight, will give a lower footprint than one which includes a CO2 “equivalent” measure for other greenhouse gases emitted during the flight and other impacts of flying in terms of climate change such as “radiative forcing”.
Another way that calculators can differ is in terms of what they measure. Some measure the amount of CO2 resulting from various activities, others also take into account other greenhouse gases and then report their impact by converting them into the equivalent amount of CO2. For example, the greenhouse gas Methane (CH4) is around 23 times more potent a greenhouse gas than CO2 , so if an activity generated one tonne of methane, it would be reported as have the same impact in global warming terms as 23 tonnes of CO2, and written as 23 tonnes CO2e, the ‘e’ indicating ‘equivalent’.
If you are interested in learning more about carbon footprinting, check out the free short modules available at the Open University Openspace website, such as “Calculating my Carbon Footprint” and “Environment: Treading lightly on the Earth“.
All this variation could make one wonder if its worth footprinting at all – but although figures vary, so long as you’re are consistent with your methodology, footprinting can still give you a good base from which to make choices and help you track your direction of travel.
which footprinting tool should I use?
There are lots of good footprinting tools out there, many available on line for free – so it’s a question of picking the right tool for the job. The website Environment Tools has a fantastic database of environment software tools, including user reviews. Here are some that stand out for us:
This government-approved calculator is designed to help people calculate their personal or household carbon footprint. The calculator also provides an action plan with a list of personalised recommendations about how to reduce carbon emissions.
Pros: It’s easy to use and can estimate household emissions if you don’t have energy consumption data to hand.
Cons: Doesn’t factor in radiative forcing, so may underestimate the impact of flying. Doesn’t include emissions relating to food or goods and services.
Low Carbon West Oxford, or LCWO, devised its own in-depth carbon calculator to be used as the start of a conversation with households interested in learning how to reduce their carbon footprint. It is designed to encourage and reward the adoption of behaviour changes such as lift sharing and recycling.
Pros: provides a comprehensive footprint, which captures the impact of small behaviour changes. The results are presented in such a way as to provide an understanding of how different parts of your life contribute to your overall footprint.
Cons: Requires actual consumption data, and can be time intensive to do the calculation.
A simple hard copy carbon calculator that gives people a best guestimate of their footprint in minutes.
Pros: Requires nothing more than a pencil and calculator to quickly rustle up a footprint in a matter of minutes, making it good for introductions to carbon foot-printing in a group setting.
Cons: Less able to tailor results based on household information in the way that Act on CO2 can, or sensitive to small changes in lifestyle like Quicksilver.
Whichever method you use, footprinting at an individual or household level can form an important first step in educating people about the impact their lives have on climate change and to introduce ideas as to how they can cut their footprint.
footprinting at a community level
You might also be interested in finding out your overall community footprint. As with footprinting at a household level, the more accurate the footprint, the more time and effort it’s going to take to calculate. You could create your own survey and use one of the tools above to calculate footprints that you then extrapolate across the neighbourhood. Alternatively, here’s an on-line resource to consider:
Energy Saving Trust Community Calculator
Based on the Act on CO2 tool, this free tool helps you build a bottom up footprint for your community. At its simplest level it provides an estimate of the carbon emissions based on housing type. It also has the option to improve the accuracy of data at a household level with questionnaires and on-line footprinting tool.
If you are going to all the trouble of surveying residents – it can make sense to combine this with a energy saving promotion activity. This is precisely what Sustainable Blewbury did when they provided home energy surveys to residents, linked to a thermal imaging exercise. These were then followed up three years later to see what changes residents had made. For further details about their survey, follow the links under “The initiative”.
For a more top-down approach DECC publishes local stats and estimates for 2009 on carbon emissions in your area.
so what else can you measure?
Ecological footprinting
Your carbon footprint is just one measure of your environmental impact. A slightly broader measure is that of your ecological footprint. This is based on the concept of “One Planet Living” – the idea that we have only the resources of one planet to live on, yet many of use consume resources at a far greater rate.
You can read more about One Planet Living and calculate your ecological footprint on the WWF website.
Oxford consultancy Best Foot Forward have also developed A Global Steps game which is a simple card game to help estimate your ecological footprint – a great activity for group sessions.
Energy consumption
One of the simplest things to measure relatively easily is the energy consumption of an area – see DECC’s Energy Consumption Statistics. You can find out the average electricity, gas and combined energy consumption at a district council level.
As with the earlier DECC emissions data, this enables you to learn more how your community compares with others, and gives more detail about how different energy use by different sectors contribute to your overall footprint.
Reducing energy in households
At a household level, people can simply call their energy company for an estimate of their gas and electricity use. The very act of regularly measuring and monitoring your home energy may help reduce your energy consumption. There are a number of ways households in your community can be helped to do this.
Real-time displays
There are a wide range of energy displays which give you real-time readings of your energy consumption – handy for spotting when you’ve left all the lights on upstairs. They vary in accuracy and usability, so check out user reviews by Which? or purchasers online. You may also be eligible for a free meter from your energy company: check with them direct. Personally, I’ve used both the Eco-Eye and OWL monitors with success. We’re also trying out the Saveometer locally, which is one of the few to measure gas consumption.
Regular readings
Keeping a regular record of your meter readings is also a useful thing to encourage households to do. There are free online tools where residents can keep their records, monitor their energy use over time, and even compare their results with others in their community and beyond.
For example, I’ve use imeasure to keep track of my household energy use – as I like the way I can see the impact of changes in the weather, holidays and changes to our home have had over time (can you guess when we had our new boiler fitted? – and look how mild this winter has been).
You might also like to check out The Carbon Account that also allows you to keep records of your travel.
If you’ve been successful in calculating your community’s carbon footprint – we’ve love to hear from you – please use the comments section to share your experiences.
Next month we move to goal setting – to share our tips and ideas for encourage householders to begin to take control of their carbon footprints.
Saskya Huggins & Jo Hamilton
