A million carbon calculators later, here I am

OK - it's time to tackle my own carbon impacts.

Sorry to get your hopes up. I can't actually begin to analyse the dozens of carbon calculators that have popped up all over the internet, but the question is, can I really understand even one of them?

Keen to become a bit more practical about my own carbon footprint, I decided to start with two sources I know of and would rely on: The Energy Saving Trust , and WWF's Counting Consumption Report. EST has a nice calculator that you can personalise and explore its assumptions. Counting Consumption looks at the UK-wide effects of consumption.

My EST carbon footprint is a mixed bag: my total is 7.86 tonnes per year, compared to a national average of 10.23 tonnes. My home energy (heating and cooking) impact is a bit below average and my use of appliances is relatively high, but my transport footprint is less than half the national average.

Is this good news or bad news?

Well, transport-wise it seems to be good news, because I don't drive much and I achieved my low figure despite generously allowing myself one short-haul return flight per year and one long-haul return flight per two years, which is probably a bit more flying than I actually do. Basically, my transport impact is low because I don't commute by car.

I'm a little irked by my appliance footprint, because all my white goods are A-rated, I don't have a TV and I turn appliances off when not using them. I suspect that it's my IT appliances that cause the spike, partly because my lack of commuting means I use computers more at home, and partly because the calculator may assume my household is using all its computing power simultaneously, which it rarely does. Nevertheless, if I am to rely on EST's calculator then appliance usage must be something to look at.

Home energy-wise, the bad news is that the things I can readily do are limited, either by lifestyle or cost. Because I work from home, my heating is often on in the daytime: I've done some work on zoning my heating so that I'm not heating the whole house to the same temperature, but the scope for reducing the heating time is scuppered. I already have double-glazing and a (fairly) modern boiler, so the real energy gains are to be found in increasing the insulation. Since I'm in a solid wall house, that not only means cost but also disruption. I'm still chasing draughts around, and that must always be a priority. The EST calculator tells me that insulation my loft could save me 1 tonne of carbon per year, which would actually reduce my home energy footprint to not much over half the national average. I have an attic room in my loft, so it would mean lining the walls and redecorating, but that just might be do-able this year.

Since appliances seem to be a problem for my household, I'm going to invest in one of those electricity usage monitors and conduct some scientific experiments on how to reduce this aspect of consumption.

So, starting from having a carbon footprint 77% of the national average, if I could wipe one tonne off my heating impacts and maybe save 20% of my appliance impacts (another 500kg) that would mean I'd made an overall 20% reduction in my own carbon footprint and would be running at 62% of national average (unless everyone else made reductions at a similar rate). This would make my household quite a low-carbon one, would it not?

Well, yes and no. For a start, I have identified 20% of savings but baulked at making much in the way of further reductions, so it's doubtful that I'd successfully continue to make carbon cuts. This is particularly relevant when my commuting impacts are minimal, because if my circumstances changed and I founded I needed to start commuting, that could easily wipe out the other gains I've made.

However, if we look at Counting Consumption we learn that in terms of ecological footprint (of which carbon accounts for about half) then our footprint per capita for food is roughly the same as that for our home and energy. So, by some crude extrapolation of the two information sources I've selected (to avoid delving into the many sources of more accurate information we could look at), we could estimate that my household's food-related carbon impact is about 4 tonnes of carbon per year. Bearing in mind that I try to avoid wasting food, don't each much processed food, do eat out quite often, grow a few of my own vegetables but would be very hard-pressed to give up eating meat, I suspect I need to do some more detailed calculations. But the real, revealing question would be, how much food (and drink) footprint could I save without noticeably giving anything up?

Over the coming months I'm going to test a hypothesis on the basis of my own lifestyle. My hypothesis is kind of threefold:

1) that there is a threshold level of personal, consumption-side carbon emissions that it is very difficult to get below, perhaps somewhere around 6 tonnes per capita per year, without a substantial change in the energy supply mix away from carbon sources;

2) that it is possible to measure and act upon personal influences on supply-side emissions, eg from energy, food, material and transport services, by focusing on the way personal behaviour affects their efficiency and impacts;

3) that this could change the way personal impact is measured and acted upon in the round.

Let's see if I can do it....

AW.