Tuesday, January 16, 2007

Carbon Week: Day 2 ~ My Carbon Footprint

As a christmas present to myself this year I decided to calculate my carbon footprint for the whole of 2006. My interest lay primarily with coming to an informed evaluation of my own CO2 expenditure - establishing a figure and thereby being able to compare it with the average UK figure (A recent study by the Carbon Trust puts the annual carbon footprint of the average Briton at 10.92 tons of CO2).

I was also curious as to what 'price' my emissions were in our newly evolving personal carbon market. There are various footprint calculators on the internet where you can enter some rough estimates (bestfootforward is a great 60 second ready reckoner, and is surprisingly accurate), but as I wanted to subject my annual CO2 count to closer scrutiny, I decided to take my examination a little further. At the end of the day I realised it would take a mathematician to work out a truly accurate picture, but I think on the basis of the information to hand, I now have a fairly rounded picture of my carbon footprint for 2006 - and a far clearer idea of my impact on the environment as an individual.

I have some advantages. I am based in central London. My electricity is supplied by Ecotricity. I do not have a car, I mostly cycle, I have easy access to and buy most of my food locally (mainly at my farmers market and local organic stores), sometimes I catch a cab, occasionally I hop on a bus.

The two main carbon groupings I examined were:
Travel - plane, train and car (kilometers used rather than miles)
Household energy use - gas

My dates are 01.01.06 - 31.12.006 inclusive, and any travel that commenced during that time-span is included in the calculation where the outgoing journey commenced within the dates but the return was thereafter.

Looks straightforward. In reality it took a little bit of doing. I compared three established sites (co2balance, The Carbon Neutral Company and Climate Care) with Defra's conversion factors. Some of the sites gave more detailed calculators; on others it was not possible to break down into individual components. It comes down to preference of use at the end of the day. All three preferred sites gave similar calculations with very little variation - nothing came widely off the mark. The difference lay in the suggested cost of offsetting the emissions, with co2balance proving to be the most expensive. For my purposes, to calculate each component, I found the easiest route was to apply to multipliers supplied by Defra (which is what most UK carbon offset schemes are based on in any event).

What did surprise me was my discovery that the multiplier used for calculating car and plane emissions are very close - x 0.16 for a small 1.4L petrol car, x 0.15 for short-haul flights. Which means that in reality if I were to drive to Edinburgh from London, as opposed to flying, my emissions would be almost the same for each journey. Where the limiting of the impact comes in is when you share your car (divide by number of passengers). Also what has not been taken into account is the fact that CO2 is far more damaging when released at a greater height. This has not been factored into aviation emission calculations, as there is still debate within the scientific community as to just what the additional multiplier should be. The consensus currently favours multiplying one's aviation emissions by 2.7 for a truer reflection. As this has not yet been incorporated into carbon calculations I have decided to go with the existing calculations for the time being.

Here is the breakdown:

Aviation x0.15
(Distance (km) x Multiplier = Carbon Emissions(kg))
Gatwick - Palma r 2620km = 390kg
Stanstead - Toulon r 2128km = 320kg
PLANE SUBTOTAL 4748km = 710kg (=0.71 tonnes)

Rail x0.04
(co2balance do individual rail calculations.
For longer distances, use Mapcrow
All of my journeys commence from central London)
Guildford r 96km = 4kg
Paris r 1032km = 41kg
Birmingham r 338km = 14kg
Winchester r 214km = 9kg
Brighton r 170km = 7kg
Bentley 68km = 3kg
Guildford 48km = 2kg
Oxford r 204km = 8kg
Paris r 1032km = 41kg
Birmingham r 338km = 14kg
Manchester r 594km = 24kg
Truro 450km = 18kg
Truro - Abergavenny 364km = 15kg
Aber - London 244km = 10kg
Basingstoke 77km = 3kg
Guildford 48km = 2kg
Paris r 1032km = 41kg
Paris - Aigle r 676km = 28kg
Other/local 275km = 11kg
TRAIN SUBTOTAL 7300km = 282kg (=0.292 tonnes)

Car Hire: small petrol 1.4L x 0.16
(For comprehensive fuel calculations, go to
VCA carfueldata)
somerset weekend 660km = 107kg
CAR SUBTOTAL 660km = 107kg (=0.107tonnes)

Electricity x0.43
Supplier: Ecotricity (renewable) = nil

Gas x0.19
(I phoned my supplier who gave me my 4 last quarter kwh readings)
6,609 kwh pa = 1,255kg
GAS SUBTOTAL = 1,255kg (1.255 tonnes)

I also examined, and with guidance on rough additional calculations from the Carbon Trust Report:
As most of my food eaten at home comes from my local farmer's market, I am safe in the knowledge that it is all raised, grown, produced, gathered, caught, or baked within 100 miles of the M25. Salamis and the like from my local Italian deli's, it has to be said travel form further afar, but Luigi assures me they are ship-freighted. So, including food miles and production of raw materials I add another 200kg. Dining out, however neccessitates a higher figure with a restaurant meal generating up to 8kg per diner. Dining out at three + times a week, I have rounded it up to 1,500kg.
FOOD SUBTOTAL = 1,700kg (1.700 tonnes)

This is difficult, and old habits die hard (Do I really have to admit what I spend on clothes?) Suffice to say I shall incorporate the figure of 300kg (for production and transport)
CLOTHING SUBTOTAL = 300kg (0.3 tonnes)

GRAND TOTAL = 4,365kg (4.365 tonnes)

Of course I'm sure this does not even begin to truly reflect the footprint of every item bought and all the other aspects that I have overlooked. But it's a start. I now have a clearer picture of my personal carbon footprint, and it makes me want to reduce it further.

With particular thanks to Dominic Stichbury of The Carbon Neutral Company for generously giving me his time and assistance on the finer points of carbon calculations.

All photos are of the west coast of Scotland - as it's so dreich and unseasonally mild down here...


Peter Hale said...

Not sure about "Electricity" though: we too are with Ecotricity but they have had a bad press and seem to be doing a fiddle with certificates. The National Consumer Council's recent report (http://www.ncc.org.uk) included the words: "Of the 25 per cent of electricity from renewable sources, some of the ‘greenness’ is being sold three times. The supply aspect of the tariff is therefore not offering any additional environmental benefits according to the definition set out in this report". i.e. it isn't green electricity!
I have asked Ecotricity for comment (none received to date; must chase); we will probably change to Good Energy and pay the bit extra.

Kyoto: 27% emissions increase for Greece.

The Lazy Environmentalist said...


Thanks for this. I shall investigate and report back. I had switched to Ecotricity over a year ago on the basis that it was sourced from 100% renewable energy (and of course my carbon footprint calculations have been on this basis).