Bookmark and ShareAndy Wimbush is nef‘s Communications Assistant and blogmaster.


The world's data servers are having an increasingly large carbon footprint | Image via TreeHugger

After my last post, there was a bit of confusion about the number of carbon ration coupons you’d need to set aside for using a computer at work. Admittedly, the ration book isn’t entirely clear about this – there’s only a certain amount of text that you can squeeze into one of those tiny squares – so I’ll clarify.

On the Energy page of the ration book, there are ten coupons, each labelled “PC use 1/2hr /day”. The “/day” means “per day”, so you need to start by working out your average daily computer use. I sit in front of a screen for at least seven hours a day when I’m in the office, but at the weekends I try to have digital detox. So my average use per day, is about five hours. Which means I need between three and four coupons over the course of a month.

If your computer use doesn’t extend beyond spreadsheets and word processors, you can stop there. But if, like me, your work involves the internet, you’ll need yet more coupons. Why? Because the internet doesn’t just rely on your computer, but also on the huge data servers that fling videos, images and text around the world. In 2006, US data centres used the same amount of power as the whole of the UK does in two months.

Since I run nef‘s blog and manage our website, I probably use the internet for maybe five out of my seven hours at work. So let’s say that’s about four hours a day average. Which means four more coupons.

All in all then, to run my computer and use the internet, I need about seven coupons a month, out of my forty allotted carbon rations.

Perhaps that seems like a lot. It’s certainly a hefty chunk out of my overall ration. Perhaps in a low-carbon economy, where we’re all working a little bit less and operating a bit more locally – so that we wouldn’t necessarily need to be in constant communication with the rest of the world – I could use fewer coupons.

But then again, why should high-tech energy usage be the first to be cut? The beauty of the carbon ration book is that it shows us that sometimes, it’s the more mundane or seemingly low-tech activities that are real climate offenders.

Take flushing the toilet. If you’ve looked at the ration book, you’ll see that water usage gets a full two pages of coupons. Why? Because the whole process of treating water – and especially sewage – emits a lot of carbon dioxide. According to Rob Hopkins at Transition Culture, it’s about  177g of CO2 for every 1,000 litres for normal water usage, with and another 322 g per 1,000 litres for sewage processing.

I rent an old and creaky flat in a probably-Georgian house in South London. We definitely don’t have an eco loo of any description. If I estimate about six flushes a day, that’s a total of 186 flushes a month. With a non-efficient loo, that means I need nine coupons.

We don’t need to dwell too much on the specifics to realise just how ridiculous this is. That’s two more rations than I need to power a computer and use the internet. If it came to the crunch and I had to decide between an elaborate system to dispose of human waste on the one hand, and Borgesian library of information, books, images, films and music, which also doubles as a communications system, on the other, I know which one I’d rather lose.

Staff at Wimpole Hall try out straw bale urinals | Photo via National Trust

The fact is that toilets don’t really need flushes. There, I’ve said it. I’m not a Luddite or a back-to-nature obsessive (I’m defending the internet!), it’s just that I’ve seen systems which work perfectly well with no water, and a tiny fraction of the carbon emissions: compost loos.

Unlike the portaloo toilets you get at festivals and outdoor events, compost loos don’t smell, they’re completely hygienic and you can recycle the waste afterwards as fertiliser. Left for a couple of years in a contained place, human waste becomes completely safe, to be used just like normal manure. All the details on how to build and maintain compost toilets can be found in the brilliant and amusingly written Humanure Handbook, by Joseph Jenkins, which has recently been made available to download as a free PDF.

For the more liquid kind of waste, the process is even simpler. Urine is full of nutrients that plants love, and, if your kidneys are healthy, it’s virtually sterile. The Centre for Alternative Technology actually advises diluting it a bit before pouring it on your veg patch, using one parts urine to ten parts water. And if this is starting to sound a bit too radical for you, you might take comfort in the knowledge that the National Trust – surely a beacon of English respectability and etiquette – has just started providing straw bales for its male gardeners to use as urinals. The bales are then added to the compost heap, which increases its efficiency. In your own garden, you can cut out the middle man and pee right onto the heap. Once again, some enterprising soul has written a book about this. Check out Liquid Gold by Carol Stenfield.

All this should completely eliminate the need for flushing the loo, saving you nine wonderful carbon rations for more interesting things. And your garden (even if it’s just plants on a balcony, like mine) will flourish as a result!

Of course, I can’t rip out my landlord’s loo and stick a compost toilet in there instead. But, I will install a Hippo, a very simple water-saving device that works in any toilet. Stick it in your cistern and save three litres of water per flush. It’ll pay for itself in less than four months. Best of all, it’ll mean I can use the “efficient” water coupons in my ration book, shrinking the number of rations needed from nine to four.

Which leaves all the more rations to spend on the internet…