12 g CO2e recycled and lightweight
80 g CO2e an elaborate bag from mainly virgin paper as supplied by many clothing retailers
A common misconception is that paper bags must be lower carbon than plastic. Wrong! The paper industry is highly energy intensive. Printed virgin paper typically produces between 2.5 and 3 kg CO2e per kilo (between 1.1 and 1.4 kg CO2e per pound) of paper manufactured. This is comparable with the emissions required to produce 1 kg (2.2 lbs.) of polypropylene plastic bags. However, paper bags have to be much heavier, so overall the paper bag ends up having a bigger footprint.
Recycled paper is roughly half as energy intensive to produce as virgin paper. But even a lightweight recycled paper bag produces slightly more greenhouse gas emissions than a typical plastic carrier.
There is another problem at the disposal end as well, which I have not factored into my numbers. Unless you recycle your paper bag, it is likely to end up in landfill, where it will rot, emitting more CO2 and, even worse, methane. Landfill sites vary in their ability to capture and burn methane emissions, but typically there will be around 500 g of greenhouse gas emissions per kilo (or around 1 lb. of gas emissions per 2 lbs.) of paper buried.1
One final detail about paper bags is that they often don’t work, resulting in bruised apples rolling down the street.
Low-carbon tips
> If given a choice between plastic and paper, the plastic one may well be best (see A plastic carrier bag).
> If stuck with paper, recycle it when you are done with it. (It is probably too much to hope that it could be fit for reuse.)
14 g CO2e a quick, expert skim on a slightly damp shirt
25 g CO2e average
70 g CO2e a thoroughly crumpled shirt ironed by unskilled hands
> Five shirts every week is about the same as a 10-mile drive once a year in an average car.
A friend of mine used to iron her husband’s socks (she’s now divorced). If you’re feeling stuck in a similar routine, I hope you will find the carbon argument gives a bit more power to your elbow.
Although ironing isn’t the biggest environmental issue, there may be scope for saving a little bit of carbon here—and perhaps some lifestyle improvement, too. For ironing that simply has to be done, the best green step is to have the clothes slightly damp and use the ironing process itself to finish off the drying. That saves both time and carbon (especially if you otherwise would be using an energy-hungry tumble drier—see A load of laundry). Even more effective is simply using the iron less often.
A few people allegedly enjoy this activity, almost as a hobby. If ironing is how you get your kicks, it works out at about 400 g CO2e per hour. That’s about five times worse than watching the average TV but dramatically better than going for a drive. I have also heard ironing described as having meditative value. I can only assume that this goes something along the lines of “a deep reflection on the resentment you notice inside yourself at spending your time in this way.” If this is you, can I recommend a good old-fashioned, Zen-style breathing routine, weighing in at zero g CO2e?
65 g CO2e powered by bananas
90 g CO2e powered by cereals with milk
200 g CO2e powered by bacon
260 g CO2e powered by cheeseburgers
2,800 g CO2e powered by air-freighted asparagus
> If your cycling calories come from cheeseburgers, the emissions per mile are about the same as two people driving an efficient car.
I have based all my calculations on the assumption that you burn 50 calories per mile.2 The exact figure depends on how fit you are (the fitter you are, the lower the figure), how heavy you are, how fast you go (the faster, the higher), and how much you have to use the brakes.
All that energy has to come from the food you eat, and that in turn has a carbon footprint. The good news is that the lower-carbon options are also the ones that make the best cycling fuel.
Bananas, of course, are brilliant (see A banana). Breakfast cereal is pretty good (let down slightly by the milk). The bacon comes in at around 200 g CO2e for a 25 g slice with only enough calories for a mile and a quarter of riding.
As mentioned above, two people cycling along using calories from cheeseburgers would between them have about the same footprint as they would have had if they had shared a ride in an efficient car. At the ridiculous high end of the scale, however, is getting your cycling energy by piling up your plate with asparagus that has been flown by air from the other side of the world. At 2.8 kg (6 lbs.) per mile this is like driving a car that does just over 5 miles to the gallon. You’d be better off in a Hummer.
All my figures include 50 g per mile to take into account the emissions that are embedded in the bike itself and all the equipment that is required to ride it safely.3 In the lower-carbon scenarios, the food accounts for only a small part of your impact, and the maintenance of bike and sundry equipment dominates.
Is cycling a carbon-friendly thing to do? Emphatically yes! Powered by biscuits, bananas, or breakfast cereal, the bike is nearly 10 times more carbon efficient than the most efficient of gas-powered cars. Cycling also keeps you healthy, provided you don’t end up under a bus. (Strictly speaking, dying could be classed as a carbon-friendly thing to do, but needing an operation couldn’t: see A heart bypass operation).
Buying a folding bike so that I could commute on the train has been one of the best decisions I have made in recent years—in terms of both lifestyle and carbon. My journey takes 10 minutes longer, but I get half an hour’s exercise and 15 minutes of reading a book each way. Because both of those are things I like doing but struggle to find enough time for, I’ve magicked an extra hour of the stuff I love into my day— while saving money and carbon.
One other thing: by taking my car off the road in rush hour, I cut everyone else’s queuing time as well and reduce the emissions they belch out while they wait (see Congested car commute).
50 g CO2e gas stove-top kettle, fairly low heat
70 g CO2e electric kettle
115 g CO2e saucepan on the gas without a lid and flames up the side
Some friends of ours have a stove-top kettle that they use on their gas stove, and we ended up debating the environmental pros and cons for months. Finally I spent half a morning measuring different methods. (A sad way of spending time, I know, but I did have a book to write.)
Our plug-in electric kettle was the fastest. Only 10 percent of the electrical energy was wasted, so although inefficiencies in our power stations and distribution systems make electricity a high-carbon way of producing heat, the electric kettle is still a fairly good way of boiling water at home.
How the gas kettle compares with the electric kettle depends on the time of year. In winter, our friends win the low-carbon prize easily. That’s because although some of the heat from the gas flames escapes around the edge of their kettle, that heat isn’t actually wasted: the kitchen is the heart of their house, so all the heat that goes into the room is useful. In their house, in fact, the gas stove is the most efficient form of heating because nothing is wasted up the flue (as it is with a gas furnace), nor is any heat sent to unoccupied rooms or lost in pipework (as it is with central heating).
In the summer, our friends still win the low-carbon prize provided they are willing to put their kettle on a small gas ring to maximize the proportion of the heat that goes into the water, rather than being lost around the sides. Doing this gives them a 30 percent carbon savings over the electric kettle but also means it takes three times as long (12 minutes) to boil. If they use large gas ring, the result is slightly more carbon than the electric kettle—and it’s still 50 percent slower.
Saucepans turned out to be less efficient than stove kettles. It only makes sense to bring water to the boil in a saucepan if you are putting vegetables in at the start, in which case there is the benefit that they begin cooking a bit even before the water boils. If you do use a saucepan, keep the lid on (20 percent waste if you don’t) and make sure the flames don’t go up the sides (potential for another 20 percent waste).
To summarize, kettles are better than saucepans, and gas beats electric—but only if you are not in a hurry or you want to heat your room anyway. Just as important, of course, is not to boil more water than you actually need.
Four kettle design improvements are worth a mention, since there are some incredibly simple features waiting to hit the mass market.
> Although only about 10 percent of the heat generated by an electric kettle is wasted, I was surprised at how hard it was to find a kettle with proper insulation. Better insulation would also mean that if you forget it has boiled, or you accidentally boil more than you need, it would stay hot for longer.
> A kettle with a thermostat so that you can set it to 85°C (185°F) when that is all you need—such as when making coffee or herbal tea—is quicker, cheaper, and lower carbon, and it probably reduces the chance of mouth cancer. The Morphy Richards Ecolectric Kettle, so far not easily available in North America, is the only one I’ve found with this feature.
> An old-fashioned whistle or a beep option would stop you from forgetting when it has boiled.
> The Eco Kettle, already on the market, allows you to decant just the amount you need from a reservoir, making it easier to boil only what you need.
The Dragons’ Den must be waiting for someone to put all these features together.
Zero CO2e plucked from the garden
10 g CO2e local and seasonal
80 g CO2e average; that’s 550 g per kilo (225 g per pound)
150 g CO2e shipped, cold stored, and inefficiently produced
> Apples are a low-carbon food wherever they come from. Beyond that it is difficult to be certain about the details.
As you’d expect, local, in-season apples are best, but there is nothing particularly bad about buying them from anywhere in the world, as long as they travel on a boat rather than a plane. Indeed, in early summer, when any local apples will have been in cold storage for months, importing may be the lower-carbon option.
One study from a university in New Zealand found that apples grown in that country for the U.K. market incurred just 185 g CO2e per kilo (90 g per pound)—significantly lower than U.K. apples for local consumption, which came in at 271 g per kilo (130 g per pound).4 The argument made in the study was that U.K. production entailed greater use of fossil fuels on the farm and required more cold storage. The study also cited New Zealand’s cleaner electricity mix. These factors, it claimed, outweighed the emissions from shipping the produce halfway around the world.
The same arguments can be applied to imports to parts of North America. Electricity in the U.S. is slightly more carbon intensive than in the U.K., but Canada’s is on a par with that of New Zealand (see Unit of electricity). The distances clearly vary depending on where you are shipping to.
A similar comparative study referenced by the U.K. government’s Department for Environment, Food and Rural Affairs (Defra) produced similar orders of magnitude but found, conversely, that for Germany (which should be similar to the U.K.) local apples were more carbon friendly than those sourced from New Zealand.5 It’s difficult to unpick the arguments and determine who got closer to the truth. Each study went about things slightly differently and made different assumptions. This story illustrates an important point: these kinds of study are always tricky, heaped with far more uncertainties and subjective judgments than many people like to admit.6
One last point: as with all fruit and vegetables, it’s a good idea to buy the most misshapen ones you can get, because that encourages the supply chain not to chuck them in the garbage before they ever reach the store.
Zero g CO2e grown in your own garden
80 g CO2e imported from the other side of the world (or 480 g per kilo/240 g per pound)
> To answer the question in the title of this book, bananas aren’t bad at all. They’re brilliant! To emphasize the point, I’m eating one as I write.
Bananas are a great food for anyone who cares about their carbon footprint. For just 80 g of carbon, you get a whole lot of nutrition: 140 calories as well as stacks of vitamin C, vitamin B6, potassium and dietary fiber. Overall, they are a fantastic component of the low-carbon diet. Bananas are good for just about everyone—athletes, people with high blood pressure, everyday cycle commuters in search of an energy top-up, or anyone wishing to chalk up their recommended five servings of fruit and vegetables per day. There are three main reasons that bananas have such low carbon footprints compared with the nourishment they provide:
> They are grown in natural sunlight—no hot-housing required.
> They keep well, so although they are often grown thousands of miles from the end consumer, they are transported by boats (about 1 percent as bad as flying).
> There is hardly any packaging, if any, because they provide their own.7
On top of their good carbon and healthy eating credentials, the fair-trade version is readily available.8
Don’t let me leave you with the impression that bananas, for all their good qualities, are too good to be true. There are environmental issues. Of the 300 types in existence, almost all those we eat are of the single, cloned “Cavendish” variety. The adoption of this monoculture in pursuit of maximum, cheapest yields has been criticized for degrading the land and requiring the liberal use of pesticide and fungicide. Furthermore, although land is dramatically better used for bananas than beef in terms of nutrition per acre, there are still parts of the world in which forests are being cleared for banana plantations9 (see Deforestation).
Overall, however, the only really bad bananas are any that you let rot in your fruit bowl. These join the scandalous 40 to 50 percent of food wasted in the U.S.10 and many other countries. If you do find yourself with bananas on the turn, they are good in cakes and smoothies. I have a distant childhood memory that they are also tasty in custard.
Zero g CO2e grown in your own garden
90 g or 500 g CO2e per kilo (230 g per pound) shipped 2,000 miles by boat and 500 by truck.
1 kg CO2e each or 5.5 kg per kilo (2.5 kg per pound) air-freighted for the start of a season
Most oranges, along with most apples and bananas, are great from a carbon perspective.11 They keep well and so can be grown in natural conditions and shipped around the world to wherever they are required.
The important thing to note here is that although there are often lots of food miles, these ones are usually fairly climate friendly. Like bananas, oranges can go on a huge boat and take their time. However, I was told by someone who buys fruit commercially that some supermarkets airfreight some varieties of orange at the start of the season to get them into the stores a couple of weeks early.
A quart of orange juice can have a footprint equivalent to several pounds of oranges. That’s because orange juice incurs several inefficiencies in its production:
> The pulp is thrown out (so pulpy varieties and smoothies may be more sustainable).
> There are emissions from processing, including pasteurizing and sometimes turning into concentrate for transport purposes, and refrigeration.
> There is the footprint of the carton.
> Transport miles are often higher as the product moves from farm to juicer to cartoner to distributor, sometimes zigzagging wildly around the world.
> Fresh orange juice requires refrigeration. In the U.K. Tesco reports that its freshly squeezed juice has about twice the footprint of the long-life product. Most of that difference will be down to refrigeration.
37 g CO2e 15-inch LCD flat screen
84 g CO2e 28-inch CRT TV
97 g CO2e 32-inch LCD flat screen
240 g CO2e 42-inch plasma screen
> One hour per day on the 32-inch LCD comes to 35 kg (77 pounds) CO2e per year—equivalent to a 39-mile drive in an average gas-powered car.
Overall, watching TV turns out to be a remarkably low-carbon hobby, and it beats anything that involves driving. This is good news because the average American spends a massive four hours a day in front of the box (compared with just three and half hours for a European and a mere three hours for a typical Canadian).12 You probably don’t because you read books and, surely, there isn’t time for both.
At its very worst, the 42-inch plasma screen, on for 10 hours per day, could clock up 880 kg (1,940 lbs.) CO2e per year,13 the equivalent of driving an average gas-powered car for about 940 miles. That may sound like a lot, but it actually makes for quite a low-carbon life, because it leaves so little time in your day to do anything else that might have a higher footprint.
The figures above don’t take account of the emissions embodied in the TV set itself. The significance of these emissions—relative to the power the TV actually consumes in use—depends on what TV you have and how often you use it. The figure of 240 kg (530 lbs.) of CO2e is a ballpark figure for the manufacture of a brand new TV costing $750, which at the time of writing is about the price of the energy-hungry 42-inch plasma version. This works out as 22 kg (49 lbs.) per year if you keep it for 10 years. If you watched that TV for 1 hour per day, the emissions from the electricity it will use, at about 80 kg (170 pounds) per year, will still dwarf those of the manufacture. At the other end of the scale, if you spend $300 on a 15-inch LCD, make it last just 5 years and watch it for only half an hour a day, the embodied emissions will dominate your TV footprint.
By watching with friends, you can clearly make things more efficient. The more people you invite around the better, provided they live within walking or cycling distance.
Should you replace your TV?
At my local waste disposal center (that’s the place that used to be called the dump in the days before segregation) they currently have a whole room especially for homeless old-fashioned CRT televisions, most of which work fine but which are being disposed of to make way for modern flat-screen models. The people who run the disposal center say that, at the peak, they were taking in 400 CRT TVs per week.
So what are the carbon implications of trading in an old television for a new one? Figure 3.1 provides some answers. All the sums are based on these assumptions that your old TV is a typical 28-inch CRT model; that whatever choice you make now, you will stick with it for 10 years; and that you will watch 1 hour of TV per day throughout that time.
In short, my sums indicate that sticking with your old TV is a good idea unless you’re happy to switch to something smaller. There are two clear winning options, each with a similar viewing experience and costing about the same over the 10-year period: a new energy-efficient 15-inch flat screen or a second-hand 14-inch CRT. Although the 15-inch flat screen has the lowest energy use, the 14-inch CRT wins overall at just 39 g per hour including the satellite receiver. But if you keep your TV for longer than 10 years, the winning option on every count is to buy the 15-inch LCD.
FIGURE 3.1: The carbon footprint of different TV options, based on watching for 1 hour per day and not replacing again for 10 years.
If you don’t want to switch to a small screen, however, sticking with the 28-inch CRT screen is the best option, because the embodied energy of its manufacture has already been written off.
So the message is that although getting a new TV does give most people a chance to improve their energy efficiency, if you don’t buy carefully, it is likely to do the reverse.
What about standby?
TVs typically use about 3 watts in standby mode, but since that probably accounts for at least 20 hours out of every 24, it means that your TV could well cause 15 kg (33 lbs.) of emissions over the course of a year even when there’s nothing showing on the screen. If you have a small, efficient TV, that could be the biggest part of its annual footprint. Only you can decide whether standby adds enough quality to your life to justify the 15 kg (33 lbs.). My recommendation is that you cut it if you can, but don’t let the issue torment you. If you spend a lot of time in front of the box, the additional exercise of switching off by hand will probably raise your quality of life slightly.
Lots of different devices around your home, all on standby at once, could collectively be more significant, and it should be said that some standby circuits use a lot more power than 3 watts. With a plug-in power meter costing about $15 you can check. No house should be without one.
Finally, it’s worth mentioning that it also takes carbon to create the programs you watch—but that is a whole other story (see World Cup).