Life in Greenhouse: my carbon footprint

I put quite a lot of effort into trying to live in a way that reduces my contribution to global warming. But it can be hard to feel you’re making much of a difference, or to know where you should focus your efforts, especially since good quality information about carbon footprints is so hard to come by.

So when the brilliant Leeds institution Bettakulcha came to the spacy eco-building where I live, Greenhouse, I decided it was not only time I gave a Bettakulcha presentation, but high time that I worked out the carbon footprint of one of the inhabitants.

Here’s the actual presentation, but you’ll probably find it quicker and better to read the written version below. I know I’m no expert in this stuff so I’ll welcome any feedback in the comments! But I hope it’s an eye-opening post all the same.

Knowing the carbon footprint of the human race is pretty easy: count up how much coal, oil and gas we burn per year (we have pretty good figures for that); work out how much forest we’re destroying and methane our waste and agriculture is releasing (trickier but pretty guessable); and throw in a few other factors, and you’re roughly there: about 50 billion tonnes carbon-dioxide equivalent (CO₂eq) per year above and beyond what the earth would be putting into the atmosphere if there were no humans around.


But working out a more specific carbon footprint is trickier. What’s the UK’s carbon footprint, for example? Again, it’s pretty easy to measure how much greenhouse gas we produce here (a billion tonnes CO₂eq per year). But a lot of oil is burned abroad on our behalf, producing food, cars, TVs, or whatever for us to import. European and American government figures tend to omit this and pretend that the emissions are on China’s tab, but obviously it belongs on ours.

All things considered, it looks fairly clear that the UK’s carbon footprint is about two billion tonnes CO₂eq per year: about 16 tonnes each. At the moment, though, the average which might be sustainable without changing the climate drastically seems to be about two tonnes per person (as, for example, in India).

But I don’t just want to know the average carbon footprint of a denizen of the UK: I want to know my carbon footprint, and then measure whether I’m reducing it.

That’s much harder to work out: while it’s easy to see how much oil the human race burns overall, it’s much harder to work out how much is to be accounted to each item produced or individual person. Take a fifteen-second powerpoint slide at Bettakulcha for example. (Yes, even a powerpoint slide has a carbon footprint!)


The slide’s carbon footprint is not just the electricity used to project it. It’s the electricity used while making the slide—and not just the electricity for my laptop, but the electricity powering the internet servers I used when researching it; a share of the energy that went into making my laptop; a share of the energy that went into making my breakfast; even a small share of the energy that went into making the software that I used. The fact that I showed the slide at a Bettakulcha event which people paid to attend probably even means that the slide contributed to economic growth—and in our world, all economic growth means more energy consumed, which means more carbon emissions.

The same problems go for working out a person’s carbon footprint: where do you draw the line in deciding what emissions they’re responsible for? So it’s really hard to work out precisely what an individual person or item’s carbon footprint is.

This also shows how deeply interconnected our carbon footprints are. I can’t unilaterally reduce my carbon footprint to 2 tonnes CO₂eq per year, because it’s actually the consequence of so many other greenhouse-gas emitting activities that are out of my control.

But I can make a reasonable overall guess about my greenhouse gas emissions, using a methodology suggested by Mike Berners-Lee, How Bad are Bananas? The Carbon Footprint of Everything (London: Profile, 2010) (from which I derived the figures above). I know (more or less) what I spend my money on, and I can find out roughly the carbon emissions per pound spent in different sectors of the UK economy. So I went through a year’s worth of bank statements (October 2011–2012) and came up with…


Of course this is still going to be a pretty blunt instrument. I usually make quite a big effort, for example, to buy food with low food-miles or environmentally-friendly consumer goods, but the measurements I’m using are just sector averages. Nor was I quite sure what I spend my cash on (though it’s mostly spent in pubs…). So this graph isn’t hugely revealing, but it’s a start.

Your expenditures almost certainly doesn’t look like this: I don’t run a car; I don’t have kids; I live in a groovy eco-flat; maybe you actually save money rather than just paying off your mortgage; etc. But hopefully you can guess from this what your picture might look like.

Now here’s how these different expenditures contribute to my carbon footprint:


Perhaps the most striking thing here is that the monetary cost of something is a pretty rubbish guide to its carbon cost (except, as it happens, in the case of goods and food). The next most striking thing is that one return flight from the UK to the US makes a HUGE difference (for these figures I followed the Intergovernmental Panel on Climate Change reckoning that aircraft emissions have 2.5 times as much effect as the same emissions at ground level). Other travel and energy use are also pretty significant.

Something this graph omits is the carbon footprint of Greenhouse itself—the emissions caused by making the concrete and steel, running diggers, etc. (I’ve only included the mortgage. Yes, mortgages have carbon footprints! They include things like the energy used by banks’ servers, the flights their executives take to broker money-laundering deals with Mexican drug-barons, etc.) It’s really hard to get good data on the carbon emissions entailed by building (and alas, the developers didn’t work out figures). And obviously a building that stands for a long time has a smaller footprint per year than one that stands for a short time, but it’s hard to predict how long a building will stand for. Greenhouse is partly renovated from a 1930s building and is partly new build. After some surfing around I got figures suggesting that a new-build 50m² ecotastic flat might have a footprint of 10–50 tonnes CO₂eq. Let’s say the building stands for 100 years: if so, that’s 0.1–0.5 tonnes per year.

Then there’s where I work, Leeds University. We don’t know the University’s carbon footprint, but for comparison, Berners-Lee reckons Lancaster Uni’s emissions at 8 tonnes CO₂eq per staff member/student per year. In the mode of accounting I’ve used, none of Leeds University’s carbon footprint is really my problem: it goes on the tab of the people to whom I sell my labour—once the taxpayer, but these days mostly my students. (As if £27,000 of debt (and counting) wasn’t disincentive enough to come to university!) But of course I still have a moral responsibility to reduce carbon emissions at work. (Actually, some of the train travel which I counted was on university business, which for this year probably cancels out the tab of building my flat.)

And finally there’s the government. Assuming that each citizen deserves an equal share of the carbon footprint of the NHS, armed forces, schools, rubbish collecting, etc., that’s another 1.8 tonnes or so per person.

So all told my carbon footprint for October 2011–2012 was up to about 15 tonnes CO₂eq, a shade under the UK average. I did well with zero-emissions commuting, low domestic energy use, and low expenditure on goods, which just about absorbed the impact of doing REALLY BADLY on flying.

So what can I do?


before you ask, offsetting, whereby I pay a company to plant trees or invest in low-carbon technology is almost certainly a rip-off (cf. Delta Airlines’ greenwash and Amtrak’s greenwash).

Obviously transport and domestic energy are the biggies. In my case, cycling saves me a lot of emissions. In theory I can make a huge difference by avoiding flying. This is hard in a job where international travel wins you prestige, and hard when you have a far-flung family, and when prices are so low relative to environmental cost. But I definitely need to campaign for less flying in professional life.

Cutting domestic energy use is hard for me because I’m already living in a building that’s more or less as green as you can get in the UK, and I use markedly less energy than the average for a one-bed flat even in Greenhouse. But ridiculously, Greenhouse doesn’t use a green energy supplier, so I’m working on changing that. If you live in any normal sort of UK accommodation, much bigger savings will be possible (and necessary) in your energy efficiency.

The finding I expected least is that if you’ve got money to burn, on average you’re better off spending it on services than goods. Don’t go shopping to pass the time: go to a film or a gig. Don’t buy an i-pad: employ a house-cleaner for 40 hours. Don’t buy five Primark jumpers: pay someone to knit one special one. Directing consumption from goods to services would probably be good news for the UK in lots of other ways too.

I can be careful in my choices of consumer goods, and I must switch my mortgage to an ethical bank. And I can adjust my diet: a thoughtful vegan diet might yield a 25% saving on a UK average diet (and a lot more if the agricultural land saved by this more efficient way of eating was reforested), so since moving to Greenhouse I’ve embraced veganry (and even some admittedly rather ineffectual but very low-carbon allotmenteering).

Doing all these things is important and worthwhile, even though there aren’t many big wins: I might hope to get my emissions down to 9 tonnes CO₂eq per year if I can only get out of those damn planes.

But the other really big thing I can do is to convince you to make similar incremental changes. Because that way we will start to have a networking effect: if I cycle to work, that’s less carbon on my students’ tab; if, when my students graduate and become bankers, they cycle to work, that’s less carbon on my mortgage. Everyone wins!


About alarichall
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