How good are Carbon Footprint calculators: part 1

OK… the first of my Carbon Footprint Calculator reviews. First, a note. I’m going to be learning about what makes a good carbon footprint calculator as I go along, so all these reviews are subject to change. And this is a layman’s response, not a scientist’s. If you’ve got any views on these – or other sites – please let me know:

1. Carbonfootprint.

What is it? It’s the site created by John and Wendy Buckley, who also sell offsets. They have kept themselves in the news recently by publishing their own estimates for the carbon footprints of Madonna’s tours and Live Earth.

Is it easy to use? Yes. The site looks a bit of a mess, but the calculator works very well. This is a conventional format calculator. It breaks down the carbon footprint into uses and then gives you a general figure for your carbon cost. If you’re just looking for a quick thumbnail overview of ‘my carbon footprint’, this probably isn’t the one. If you want a good audit of your household energy use, this one looks good. It asks pretty specific questions, but in a practical way. For instance, you can enter your electricity use either in kilowatt hours, or in pounds. Also to its credit, it has lots of categories which other carbon footprint calculators don’t – for train journeys, underground journeys, even LPG use etc. The detail on this stuff is great.

How accurate is it? The figure for my carbon footprint came out higher than the other calculations I’d done… While household figures are nailed down, the figures for plane flights only have loose categories short-haul, medium-haul and long-haul. It’s definitely stronger on household use, so not great as a business carbon footprint calculator. However, ease of use is great, and while I’m sure it’s pretty accurate, I’m not sure where they’re getting their figures from as they don’t reference their sources.

2. The Carbon Calculator

What is it? This is a site designed – by the look of it a couple of years ago – by the University of Warwick’s Carbon Footprint Project Group.

Is it easy to use? One of the problems with these calculators is working out how to ask the right questions. These days we all have our bills calculated differently. The main problem is trying to match the data householders like us have, with the details they want. They’ve made a good stab at keeping this conventional energy calculator flexible. Also there’s a shopping calculator – to work out the extra carbon footprint of your weekly shop – though it’s short on detail and will only give you a thumbnail figure.

How accurate is it? Most sites tend to try not to fox you with the fine print, but the difficulty is you can’t see how they’ve worked things out. Are they plucking figures out of thin air? The big plus with this site is that they show the workings out on a separate page. They’ve used fairly simple formulas – for instance they estimate that one kilowatt of electricity equals 0.47kg of carbon, which is a slightly higher figure than other calculators. The New Scientist recently quoted a figure of 0.43kg per kilowatt. Which is the right figure? That’s where a layman like me has to hold up his hands and say, “I don’t know.”

So… what I’m learning is that these carbon footprint calculators are OK as a way of self-chastisement, a way of nudging ourselves to change our ways, but if we’re going to take them seriously as a way of radically altering our lifestyles, and actually reduce our carbon footprint, we’re going to have to find ways to trust what they’re saying more.

Photo by Andy