NOW Cop26 has drawn to a close, you may be left feeling a little befuddled about how best to do your bit for the planet.
Does it make sense to stop eating imported fruit if you plan to fly to the sun for some much-needed family time next year?
Is a shower more eco-friendly than a soak in the tub?
To answer such questions — and help us better understand the implications of our consumer choices — PROFESSOR MIKE BERNERS-LEE, professor of sustainability at Lancaster University, has calculated the carbon footprint of absolutely everything . . . with some surprising conclusions.
Like most people I don’t particularly enjoy instructions on how to live.
I may have spent 15 years researching the impact of the carbon emissions that are slowly heating our planet.
But I’ve also had plenty of practice in not being quite as good as I’d like to be.
We all want to live our lives responsibly but we have to live. That’s not to say we don’t need to change our habits. We do. We are in a climate emergency. But a sense of scale is required.
A friend once asked how he should best dry his hands to reduce his carbon footprint — with a paper towel or electric drier? This same person flies across the Atlantic dozens of times a year.
The flying is hugely more significant than the hand-drying, so my friend was just distracting himself from the real issue.
Professor Mike Berners-Lee: We all want to live our lives responsibly but we have to live. That’s not to say we don’t need to change our habits. We do. We are in a climate emergency. But a sense of scale is required
The reason I decided to work out the carbon footprint of everything I could think of was to help you get a feel for roughly how much carbon is at stake when you make simple day-to-day choices.
Everything we do has some impact — where we travel to and how, whether we buy an apple in season or asparagus in winter, whether we have a quick shower or luxuriate in the bath.
What is a carbon footprint? It’s a measure of the impact of our activities on the amount of greenhouse gases being produced and released into the atmosphere.
All we consume and do and think about, both at home and work, has a carbon impact — that is, a climate change impact.
But you might be very surprised by some of the things that have a hefty carbon load and some that don’t.
I use a measure called ‘carbon dioxide equivalent’ to calculate the volume of harmful gases (carbon dioxide, methane, nitrous oxide, refrigerant and other gases) generated in the making and consumption of any product or service.
Take a tomato: any calculation needs to take into account how it was grown (naturally or in a heated greenhouse), the type of fertiliser used (some require a complex manufacturing process, others emit greenhouse gases), and how it was packaged and transported (by road, ship or air, the latter being a carbon disaster).
As a consumer, you need to consider that 1kg of locally grown tomatoes has a carbon footprint of 400g CO2e compared to an astounding 50kg CO2e produced by 1kg of organic, ‘on the vine’ UK cherry tomatoes grown out of season in March.
Choose those tomatoes and they can be the highest-carbon food of all, even though grown here.
Out-of-season cut flowers are bad news for climate change, because they either have to be put on a plane to get here or grown with artificial heat – a single red rose may be romantic, but when grown in a Netherlands hothouse or outdoors in Kenya and airfreighted to Europe, it will set you back 2.4kg of CO2e compared to zero carbon for a rose grown in your own garden
Bananas, on the other hand, may travel far before they land in our fruit bowls, but as they tend to be shipped rather than airfreighted and require less packaging because they are protected by their skins, they are a low-carbon — and extremely nutritious — food.
ALL THAT GLITTERS IS BAD FOR PLANET
Gold and diamonds are precious precisely because it takes effort, industry and resources to extract them, and this takes their carbon footprint sky high, particularly for jewellery which comes from far afield (£500 worth of gold and diamonds from Africa has a carbon footprint of 710kg CO2e).
That’s aside from the bad working conditions for some miners. Far better to wear jewellery passed down through the family, re-fashioned from existing gems or made from natural materials like shells.
GROW YOUR OWN BOUQUETS
Out-of-season cut flowers are bad news for climate change, because they either have to be put on a plane to get here or grown with artificial heat.
A single red rose may be romantic, but when grown in a Netherlands hothouse or outdoors in Kenya and airfreighted to Europe, it will set you back 2.4kg of CO2e compared to zero carbon for a rose grown in your own garden.
A bouquet a week of imported flowers could add 1.5 tonnes of CO2e a year per person.
Grow your own flowers or look for bouquets of local-grown, seasonal blooms (1.7kg CO2e for 15 UK outdoor-grown stems).
An alternative is indoor plants, which are far less carbon-intensive.
DON’T FEEL GUILTY ABOUT A DISHWASHER
A high-efficiency dishwasher always wins on carbon footprint over washing the dishes in hot water as long as you run a full load, and particularly if you set it to run at night when electricity demand is low and the grid becomes more efficient
A high-efficiency dishwasher always wins on carbon footprint over washing the dishes in hot water as long as you run a full load (between 470g to 600g of CO2e per full load) and particularly if you set it to run at night when electricity demand is low and the grid becomes more efficient.
Rinsing plates before stacking the machine is the worst option and ranks alongside ironing your spouse’s socks. If this is your routine, liberate yourself, sharpish.
ORDER A COFFEE WITHOUT MILK
The quickest way to slash the carbon footprint of your morning coffee (or tea) is to drink it black (49g of CO2e per cup for instant coffee or 87g a cup for a black filter or Americano compared with 235g CO2e for a large cappuccino).
Cow’s milk has such a high emissions toll that even the splash in tea accounts for three quarters of a cuppa’s carbon footprint. For a large latte (552g of CO2e) you could have nine Americanos or 25 cups of black tea.
If you buy takeaways, add 110g of CO2e for the disposable cup. At home, use one sturdy mug and only wash it at the end of the day.
JUST HOW BAD ARE IMPORTED BANANAS?
The distances bananas travel to reach us are vast.
But at just 110g of CO2e each, bananas are actually a great food for anyone who cares about their carbon footprint.
Grown in natural sunlight with no hothousing required, they keep well.
So although they are often grown thousands of miles from the end consumer, they are transported by boat (about one per cent of the carbon footprint of airfreight) and they require hardly any packaging as they have skins.
The only really bad bananas are those you allow to rot in your fruit bowl.
These join the scandalous 22 per cent of food binned by consumers in the UK.
Use overripe bananas in baking or enjoy with lashings of custard.
GO FOR THE UGLIEST APPLE IN THE SHOP
Buy the most misshapen apples. It encourages the supply chain not to chuck less-than-perfect-looking fruits away.
Apples are low-carbon but local and seasonal is best (32g of CO2e per kg). This changes when out of season.
UK apples bought in early summer will be last year’s fruit, which will have been kept refrigerated, so requiring electricity. This makes imported apples (80g of CO2e per kg) a better option.
Although they are often grown thousands of miles from the end consumer, bananas are transported by boat (about one per cent of the carbon footprint of airfreight) and they require hardly any packaging as they have skins
NO WINTER ASPARAGUS
Perhaps the single most carbon-intensive winter vegetable is fresh asparagus flown in from Peru (4.7kg of CO2e per pack.)
That’s because a mile by air typically has about 100 times the carbon impact of a mile by sea. The same applies to airfreighted baby corn, baby carrots, mangetout, green beans, fine beans, okra, shelled peas, lettuces, blueberries, raspberries and strawberries.
Enjoy lashings of UK asparagus in summer (270g of CO2e per pack) then wait a year to eat it again.
THE SCOOP ON THE MOST ECO ICE CREAM
A soft scoop from a van comes with a hefty carbon price tag of 500g of CO2e per cone as the vanilla ice cream’s dairy-based and kept cold in a less efficient mobile refrigeration unit, often belching out diesel fumes.
A chocolate flake makes the footprint of an ice cream higher again, though perhaps we can agree this is a necessary evil.
Opt for a plant-based ice cream for your cone, instead. Better still, buy a choc ice (140g of CO2e) or an ice lolly (70g of CO2e) from a shop, which has a lower figure as its refrigeration will be more efficient.
CROCS ARE TOPS
Shoes vary a lot in their carbon footprint, depending on what they’re made of and how long they last.
Running shoes made in China might come in at 8kg of CO2e a pair, but specialist leather is more (15kg of CO2e).
At the lowest end of the scale are a pair of Crocs, made with just 250g of expanded EVA (foam rubber).
They are sold unpackaged so the carbon toll is just over 1kg CO2e per pair.
Shoes vary a lot in their carbon footprint, depending on what they’re made of and how long they last. Running shoes made in China might come in at 8kg of CO2e a pair, but specialist leather is more (15kg of CO2e). Crocs are sold unpackaged, so the carbon toll is just over 1kg CO2e per pair
ARE REUSABLE NAPPIES THAT SAINTLY?
A cloth nappy may seem better than a disposable but if washed at 90 degrees and tumble-dried to soften, it’ll carry a higher carbon footprint (165g of CO2e per nappy) than a disposable (130g per nappy).
The lowest carbon option is reusable nappies washed at 60 degrees, line dried, and passed on to a second child (60g CO2e per nappy).
Up to 20 per cent of the carbon footprint of a disposable nappy arises from the methane it emits as it rots down in landfill.
Biodegradable disposable nappies break down more rapidly in landfill so give off more of the gas.
WINE BOXES OVER BOTTLES
The bottle usually has a bigger footprint than the wine. Shipping is only a small part, so it doesn’t matter much where your wine comes from.
Far more important are the road miles — in your country and the country of origin.
For this reason, locally produced wine could cut the footprint by 20 per cent (1.3kg CO2e a bottle from Britain or France) and, oddly, I estimate Australian wine shipped to the UK (in huge sealed tanks) probably has a slightly lower footprint (at 1.4kg) than Sicilian transported in bottles by road (1.65kg).
By buying wine boxes or cartons you can reduce the footprint by a factor of about five.
A cloth nappy may seem better than a disposable but if washed at 90 degrees and tumble-dried to soften, it’ll carry a higher carbon footprint (165g of CO2e per nappy) than a disposable (130g per nappy)
EAT FROZEN BERRIES WHEN IT’S COLD
Fresh strawberries flown in from South Africa in winter or those grown in a hothouse come with an eye-wateringly high carbon cost of 3.65kg CO2e for a 250g punnet.
Far better to eat UK strawberries in summer. Or opt for frozen British berries (770g CO2e for 250g) which are super-nutritious and easier than fresh fruit to eat without wastage, as you can take just what is needed from the freezer.
NEVER, EVER FLY BUSINESS CLASS
Flying, particularly long haul, is bad for the planet. Emissions from airborne planes have a greater impact on greenhouse gases than those burning the same amount of fuel on the ground. A business class seat, as it takes up more room, has a greater percentage of the flight’s total carbon footprint. A single flight is equivalent to using 340,000 plastic bags.
If you do fly, choose economy. Go abroad less often, stay away for longer and only fly to do something you can’t do here in the UK.
RATION BATHS AND TIME YOUR SHOWERS
abandon a daily bath, folks — just have one a week. A quick dip can be anything from 500g to 1.5kg of CO2e depending on your heating system.
Far better to have a quick, daily shower. Five minutes is 160g to 250g of CO2e (depending on your hot water system). You could treat yourself to 15 minutes under a power shower for the 1kg of CO2e you generate running a hot bath.
ONE TAP THAT YOU SHOULD TURN ON
At 400g of CO2e per litre, bottled water is 1,000 times more carbon intense than tap water, so it really pays to ditch the plastic bottles.
The carbon emissions come mainly from packaging and transport, but add 83g CO2e per litre for the plastic, and 20g CO2e to melt the plastic pellets and mould them into bottles.
Transport is also significant because water is so heavy.
SWAP YOUR CAR FOR THE TRAIN
Trains are generally a lot greener than cars, though a good petrol car can beat a train’s carbon footprint if the car is full of people. Even two people travelling together are better off driving an efficient car than travelling first class by train.
The carbon cost of a train trip depends on how fast it goes (air resistance increases with speed), how many stops there are (each stop wastes energy) and type of fuel used (electricity beats diesel).
Travelling by an Underground train is lower-carbon per passenger mile than an intercity train (68g of CO2e) — mainly because people are packed in so tightly.
YOU MUST EAT YOUR (SOURDOUGH) CRUSTS
Homemade sourdough or locally baked artisan loaf has a smaller carbon footprint than mass-produced sliced bread (630g of CO2e per loaf compared to 1kg of CO2e for mass-produced)
Homemade sourdough or locally baked artisan loaf has a smaller carbon footprint than mass-produced sliced bread (630g of CO2e per loaf compared to 1kg of CO2e for mass-produced).
More than 60 per cent of the emissions of all bread production comes from the wheat cultivation (and most of that is the fertilizer used). A third comes from the milling and baking.
Transport is a tiny fraction if bought locally. Buy only what you need and always eat the crusts! Food waste thrown into landfill is very bad news.
Rice, unlike bread, is a surprisingly high-carbon staple (at 4kg to 7.1kg of CO2e per kg depending on planting practices).
This is due to the methane that bubbles out of the flooded paddy fields and the carbon-excessive nitrogen fertilisers that are often applied. This means a kilo of rice can cause more emissions than burning a litre of diesel.
Adapted by Louise Atkinson from How Bad Are Bananas? by Mike Berners-Lee, Profile Books, £9.99. © Mike Berners-Lee 2020. To order a copy for £8.99 (offer valid to 12.11.21, UK P&P free on orders over £20), visit www.mailshop.co.uk/books or call 020 3176 2937