The Upfront Carbon of Everything From Tea to Jeans

When thinking about carbon emissions, people usually only worry about the energy of operating something. But making anything involves emissions from the materials used and the assembly to the transport and delivery. The carbon emitted while making stuff—the upfront carbon—is an essential part of the carbon emission discussion.

I teach sustainable design at the Creative School of Toronto Metropolitan University, and this year focused on the upfront carbon of everything. I wanted students to get an idea of how things are made and what the emissions of each stage of production were.

They were asked to do a one-page infographic and a three-minute video explaining their object of choice. Loosely modeled after Mike Berners-Lee's book, "How Bad Are the Bananas," they each picked an object and tried to find the data, which is not easy, and figure out the total. There were some shockers and some wonderful surprises.

Black Tea

If you like a cup of black tea, you're in luck. It's only 23 grams and could be a third less if you choose loose tea instead of a bag, which we strongly recommend. The problems of tea bags go beyond the carbon footprint but also, they are a major source of microplastics. This was one of my favorite submissions, because of the detail but also the presentation with the lovely drawings.

Crayon

If you want to draw, consider the crayon at only 57 grams. It's an interesting product in that it is still made the old-fashioned way, with paraffin that comes by ship from Canada, mixed with pigments in Pennsylvania, then wrapped in paper that is stiffened with corn starch.

Shoe Box

I did tell the students that they could pick any object, and there were some interesting choices, such as this Nike shoe box. At 196 grams of carbon dioxide, it is not a huge deal, but it shows how companies can make choices that reduce their carbon emissions.

For instance, we can acknowledge the need for a box to protect and handle the shoes. But the printing on the box is a quarter of its footprint and is seen by how many people for what proportion of its life? What function does it actually serve? How many boxes does Nike sell in a year, times 46 grams of carbon that would be saved if it didn't print on the entire box?

Cinnamon Buns

This is one of my favorite ones, with yummy illustrations to go with a yummy cinnamon bun. The cinnamon seems a bit high at 509 grams, and I couldn't figure it all out until I was told that these numbers were for a tray of six buns, which is then divided up to get the single bun at the end.

Staedtler Pencil

Like the crayon, the pencil has been around forever, or at least since 1795. What is so fascinating here is that the Staedtler pencil is made in Nuremberg from California cedar, Pennsylvania clay, and Turkish graphite. Then it is shipped back to North America, where my student includes the 195 grams driving it from the Staples store to her house.

This is probably a bad design of the assignment on my part because it is not relevant information in this particular case and is perhaps not accurate. The standard unit for carbon emissions from transportation is the CO2 per kilogram per metric ton, and the weight of a pencil is negligible. So really, the pencil is probably 190 grams of CO2.

One Liter of Milk

Milk causes serious emissions, mainly due to the methane from the cow. All dairy products are problematic because of this. When I was writing my book, "Living the 1.5 Degree Lifestyle," cheese was one of my biggest problems, especially since my daughter is a cheesemonger and I have access to some of the best cheese in the country.

A Bottle of Wine

Fortunately, the wine that one pairs with that cheese is not bad at all, with a bottle of wine coming from Europe only slightly higher in carbon emissions than a liter of milk from down the road. It is shipped mostly by sea, which has a very low carbon footprint; that's why in New York City, French wine has a lower carbon footprint than California wine.

A Dozen Eggs

None of this is easy to do, and many of these numbers are approximations. The point of the project was to have the students understand the complexity of the issue and not necessarily come up with a number that is going to be peer-reviewed.

For instance, here are a dozen eggs from Alberta, Canada, where it is very cold much of the year. I can't imagine that those free-range chickens spend much time roaming the countryside, and it must take a lot of energy to heat those barns. I often checked numbers against those in "How Bad Are the Bananas," where Berners-Lee found that half a dozen English eggs had a footprint of 2 kilograms of CO2.

He wrote, "If you have ever been inside a commercial chicken shed, you'll probably have been shocked by the heat pouring out—a visceral illustration of the inefficiency of animal farming. All that heat is energy lost in the process of turning chicken feed into eggs." In much colder Alberta, the numbers might be much worse.

Jeans

The carbon footprint of clothing was consistently shocking, particularly since we know how much of it is worn just a few times. Three students studied jeans, and they all came in at about 20 kilograms. It is no wonder that the carbon footprint of the fashion industry has become such an issue. T-shirts came in at around 6 to 10 kilograms, and shoes at 15 kilograms. It all adds up fast.

Gold Necklaces

Sometimes, the results are just shocking. This is a 5.71-gram gold necklace, where so much rock is blasted, hauled, and processed that 164.89 kilograms is emitted in making a necklace that weighs almost nothing. I didn't believe the numbers, and clearly, neither did the student who compared her result to four other sources. Gold has high value and lasts forever, but isn't exactly a necessity of life.

While 253 kilograms of CO2 sounds like a lot, it's not much compared to a car that might clock in at 100 times that.

Lessons & Learnings

This was one of the big lessons that I hope the students learned from this exercise. When it comes to operating emissions that come from heating a house or driving a car, efficiency can make a big difference. But when it comes to the upfront or embodied carbon emissions, efficiency matters a lot less; you can only squeeze so much out of a pair of jeans. The issue now becomes one of sufficiency: Do I need a second pair? Do I need a gold necklace? Or, for that matter, can I ride a bike or e-bike instead of driving a car? How much do I really need?

I let the students choose their own topic, so this isn't a very broad range of stuff; nobody picked a hamburger or an iPhone, or even a car. If I were to do this over, I would have them pick an object off a list or assign them randomly. There were also some fairly consistent problems:

Almost nothing is transported by air freight other than really short-lived products like flowers, as my student notes in the video above, or really high-value products like gold chains and iPhones. Everything else comes by ship, which is very efficient. One student doing a cup of coffee flew it from Ethiopia, and a cup came out at 25 kilograms; it is about 80 grams.

Transportation was the most difficult number for many students, mostly because of math errors. One student submitted a pair of jeans at 529 kilograms of carbon, including 500 kilograms for shipping. He put in the number for the entire container instead of dividing it by the number of pairs of jeans.

Another had a watermelon transported 100 kilometers with 23,226 kilograms of emissions. I could have hired an Uber limousine to deliver it with a lower footprint.

Another student calculated the footprint of a single sheet of paper at 28,192 grams of carbon emissions, including 27,637 grams of transport. I did the math and calculated the transport at 0.559 grams.

What surprised me about these is that the number didn't just pop out at them—27 kilograms is a lot of weight; 500 kilograms is a small car. It's not like they think in pounds. These are young Canadians who grew up with the metric system. Perhaps I should have sent them to the gym and said, "that's 20 kilograms" because I rarely got the sense that people grasp how much carbon dioxide we are talking about because of course, gases don't have any apparent weight.

In the end, I do not believe my students and I are giving Berners-Lee a run for his money. The choices of items didn't cover a very broad range, many had a hard time finding good data, and probably because I gave them insufficient instruction, the definition of what is upfront carbon was inconsistent and so were the numbers.

It's also almost impossible to draw boundaries, like the student who included the drive to Staples to pick up her pencil. One student, doing a latte but whose work I cannot show because she had proprietary information from her coffee shop employer included the "4.6 miles on the subway to work multiplied by the CO2 per passenger mile of a subway system" and then calculated the percentage of her hours compared to all the staff and the percentage that thelLatte was of the day's sales so that she could calculate that her commute added 6.31 grams to the oat milk latte. If one follows this logic, we should also include the heating of the café and the embodied carbon of the building it sits in.

Notwithstanding the caveats and the problems, I do believe that the message got through: Everything, from the 4.1 grams from a plastic straw to 68,000 grams of an Intel CPU, has an upfront carbon footprint. The less stuff we buy and the longer we keep it, the lower our carbon emissions will be. It's all about sufficiency.