'Carbon footprint' is a conceptually flawed idea

We cannot draw lines around ourselves and allocate blame to individuals

I wrote a master’s thesis on individual environmental footprints and published some of the results in this paper in the Energy Policy journal a decade ago.

This research was part of a bigger literature that began decades ago showing the problems with the idea of a personal carbon footprint. But for some reason, the carbon footprint idea has now become even more embedded in our culture and policy debate.

For example, this concept regularly comes up in debates about urban growth and housing policy.

Calculation problems

Think about how a carbon footprint is calculated.

We must start with the point sources of emission of carbon dioxide and other greenhouse gases, either from burning liquid fuels (ships, planes, cars, etc), gases (at home, in power plants, etc), and solid fuels (coal, wood, etc).

Then we must assign blame for these relatively few sources of emissions to every individual on the planet.

Consider how hard this is. For example, how do we assign blame for the emissions from the truck used to deliver concrete to build a hospital in my town?

One way is to assume that because those emissions are created in the process of building a hospital, they are embedded in that hospital, and anyone who consumes services at that hospital is assigned blame proportional to the market value of their usage of hospital services.

This is the usual way of doing it, and why the term embedded emissions or embedded resource use is now a common phrase. The logic here is that blame follows the flow of material production and is assigned to the final consumer for all upstream production emissions.

Another way would be to assign blame for emissions using financial flows. Since the concrete company directly creates the emissions from the truck they own, we can say that those emissions are embedded in the incomes earnt by the financial beneficiaries of the concrete company, being the owners and the workers.

Sometimes you hear that emissions are embedded in the incomes of people, such as when you hear that certain few companies are responsible for an enormous amount of greenhouse gas emissions.

There is no reason to choose either way. The production flow way assigns blame to individuals based on what they consume, and the income flow way assigns blame to individuals based on what they earn.

Neither really makes much sense.

Economic problems

But it gets worse. The mapped relationships between sources of greenhouse gas emissions and each individual’s consumption or income change when consumption and production decisions change. The relationships are not fixed, so we can’t leverage them to make system-wide changes.

Think about it.

Many people think that if we all stopped driving petrol-powered cars and decided to drive electric cars instead that it will have a major effect on greenhouse gas emissions and the temperature of the earth in a few decade’s time.

The logic here is that there is a mechanical relationship between the way blame is assigned for emissions from the vehicle one owns to their personal consumption choice.

But if we all switch to electric, then there are system-wide offsetting effects known as rebound effects.

Now, instead of consuming petrol in your vehicle, you are consuming electricity. The demand on the grid stimulates more investment in electricity production from generators, who may use more coal, gas, or oil, depending on your location, creating more point sources of emissions elsewhere in the economy.

Changing what you consume also changes what it produced and how it is produced, which changes the ‘blame mapping’ itself.

Even if you decide to avoid this problem by spending less of your income altogether, saving most of it, this has economy-wide offsetting effects.

If many people collectively start saving, reducing demand in the economy, we take policy action to stimulate more production and employment, and all that economic activity will be powered by some fuel source.

Incomes

A final point about the carbon footprint is that it ends up allocating blame via consumer goods and services or incomes earnt, then those with the highest income households who consume the most goods and services end up with the blame.

If the mechanical logic of the carbon footprint is useful, as many think, then the solution to embedded greenhouse gas emissions is to have fewer consumer goods and services. In short, be poorer both individually and collectively.

Redistribution won’t cut it, since then poor people who become richer simply add more greenhouse gas emissions.

Yet no one in a rich country travels to a poor country and observes their air quality and environmental amenity and thinks that this is a solution to environmental problems.

Traditionally, environmental problems get solved in rich countries by directly regulating land use, fuel use and emissions standards when used, and directly creating institutions to deal with waste of all sorts.

No one thought the solution to lead pollution in the 1970s was to consume less and be poorer because of the embedded lead in consumer goods. We took direct action. And we could do that because we had a clear definition of the problem.

Unfortunately with greenhouse gas emissions, we don’t have a clear understanding of the problem—after all, the fact that the concentration of carbon dioxide in the atmosphere is rising doesn’t automatically make it a problem. We need to understand the real negative (and positive) effects on people.

Because we don’t have a clear understanding, we can easily get distracted by ideas like carbon footprints that make little sense and can’t really help us directly tackle the climate problems, whatever they are.

---

In case you missed it, I talked about some of these ideas and more about effective environmental policy in this podcast.