UPDATE: Since originally publishing this post in November of 2013, I’ve done a lot more inquiring into and asking people about terms, and I’ve eventually come to the conclusion that my original term “k-coe” can be improved on, as it’s a little too strange to write and to say. I’ve settled on the new word “kic,” to mean the same thing: Kilograms of carbon dioxide equivalent. Apart from the change in the exact term, the rest of this article, explaining why the unit is important and helpful, still applies.
In my last post, I mentioned how useful I found Mike Berners-Lee’s book on carbon footprints, How Bad Are Bananas: The Carbon Footprint of Everything.
I also mentioned that there are some things about the book that I think fall short. One of those is units of measurement. Almost everybody I’ve read on the subject of carbon footprints, so far, does this same problematic thing, so I don’t blame Berners-Lee specifically, although he’s worse than most.
Here’s the thing: people use a whole bunch of different units to measure carbon footprint depending on the situation. This habit comes very reasonably from scientific tradition, in which it makes sense to have micrograms, milligrams, grams, kilograms, metric tonnes, etc. so as to keep numbers manageable. Berners-Lee, in publishing the American edition of his book, makes it worse by also converting many numbers to so-called “English” units and talking about pounds and tons of CO2 equivalent right alongside kilos and metric tonnes.
But if having these different units is common practice among scientists, grocery stores, governments, cooks, and many other relatively sensible sources, what’s the problem? In a word: impact.
The conversion to English units is the worst in this respect, because it throws two numbers at us simultaneously. For example, Berners-Lee gives these numbers for an average hotel stay: “24 kg (53 lbs.) CO2e: $100 spent on dinner, drinks, bed, and breakfast in a hotel with average eco-credentials.”
Don’t blame him for all the of details and qualifications: as described in my last post (“Measuring Carbon Footprint: Flawed, but Essential“), they’re important.
However, not counting the price of food, he throws two different numbers at us: 24 and 53. Since most of us don’t have a clue what the impact of either a pound of CO2 equivalent or a kilogram of CO2 equivalent means in terms of climate change, what sticks out are the raw numbers. By comparison, here are Berners-Lee’s numbers for a couple of other items:
- bananas: “80 g CO2e imported from the other side of the world (or 480g per kilo/240g per pound)”
- a hectare (2.5 acres) of deforestation: 500 tons CO2e.
With all of those units thrown at us, we may intellectually understand that we’re counting things differently in each example, but our brains are not configured to easily distinguish between differing units when we’re being presented with a list of numbers. On some level we have to fight against the intuitive idea that a hotel stay is 24 or 53 whatevers, a banana is 80 whatevers, and a hectare of deforestation is 500 whatevers.
If we want people to really understand the relative climate change impact of different choices, we need to standardize on a single unit and not try to keep numbers small by changing what we’re counting. Let’s adopt the single most widely-used and well-understood unit, kilograms of CO2 equivalent. Further, let’s call it something short and easy and distinctive so that normal people can use the term: I advocate for “kic,” pronounced like “kick.”
I know that’s a weird word, but I think a weird word is necessary. We could abbreviate to “kce” and call them “kaceys” or something, but that sounds much too cute and innocuous. It would be like calling a nuclear bomb “Mr. Kablooie.” It’s a bad idea to make life-threatening destruction sound friendly. We’ve even got a number in there, so a straightforward acronym like “KCO2E” is unpronounceable. So is “KCDE” for “kilograms of carbon dioxide equivalent.” My first attempt at a compromise was “k-coe” or “kcoe,” but it’s just too unwieldy. People can say, spell, and remember “kic,” even if the spelling is odd.
One benefit of a strange (but easily-pronounced) word is that it draws attention to itself. If I say “Hey, we could save 5 kics if we take our bikes instead of driving,” the natural response is “What’s a kic?” (or “what are we kicking?”). That gives an opportunity to answer “A kic is an easy way of comparing climate change impact. It stands for ‘kilograms carbon dioxide equivalent.’ I’m trying to get mine down to 2,000 kcoes a year, but it’s a long, hard slog.”
Most normal people, on hearing this, will almost instantly forget the technical details, but the word and how it’s used may stick, and the numbers make easy reference points. Anyone can see that saving 5 kics if you’re trying to keep your impact down to, say 10 kics per day, is a smart move.
So what do the above examples look like if we use kics?
- A hotel stay: 24 kics
- A banana: 0.08 kics
- A hectare of deforestation: 500,000 kics
To me, that’s much, much clearer. I instantly understand a lot more of the relative impact of these different actions than I did with the differing units.
One thing Berners-Lee does that I think is very smart is to compare a lot of things to what he calls the “ten ton(ne) lifestyle,” which is to say a lifestyle in which a person’s footprint is 10,000 kics per year. (Note that I can say “footprint” instead of “carbon footprint,” because the term “kics” already tells us that we’re talking about greenhouse gases.) Berners-Lee is much more comprehensive than many sources in carbon footprint estimation, so while that may sound high, it’s a good bit lower than what most of us in the developed world are actually doing. Regardless of whether we choose that target or a much more ambitious one, like 2,000 kics per year per person, using kics for both the target and the impact of each choice becomes very useful. We can compare apples and oranges and bananas and cheeseburgers and make informed decisions. We can look at how we’re doing in comparison to a goal and figure out what scale of change is necessary to meet it.
All of this becomes hopelessly complicated with multiple units for everything. Let’s stop making a confusing subject even harder to understand.
I know that something as picky as how we talk about climate change numbers seems trivial, but I think it’s the difference between the subject being permanently vague and confusing and it being crystal clear. I believe that clarity and understanding are desperately needed if we want to see any widespread improvement in how people think about climate change.
If you agree, please spread the word about this term. You don’t have to link to this site or give me credit for the idea or spell it the same way: for all I care, attribute it to Tom Hank: that might even be better for popularizing it. Let’s just agree to line up our numbers and talk in a language everyone can understand.
Photo by sidelife