Externalised costs and the human on the bicycle
Remember the most common question the protagonists of the eponymous British sitcom The IT Crowd asked a caller checking why a computer wasn’t working? “Have you tried turning it off and on again?” Nine times out of 10, this fixed the problem, whatever it was, and the IT team could get on with its life.
Around COP26 or so, I acquired a similar habit: every time someone presented something as a model of energy and/or cost efficiency, my first thought was whether they’d included the externalised costs. This is clearly a global problem today yet many people continue to overlook it in contexts big and small. So when I came across a neat graph on Bluesky (shown below), drawn from an old article in Scientific American, I began to wonder if the awesome transportation efficiency of the human on the bicycle (HotB) included the energy costs of making the bicycle as well.
According to the article, written by an SS Wilson and published in 1973, the HotB required 1-2 calories per gram per km to move around. The next most efficient mover was the salmon, which needed 4 cal/g/km. If the energy costs of making the bicycle are included, the energy cost per g/km would shoot up and, depending on the distance the MotB travels, the total cost may never become fully amortised. (It also matters that the math works out only this way at the scale of the human: anything smaller or bigger and the energy cost increases per unit weight per unit distance.)
But there's a problem with this line of thinking. On a more basic level, neither Wilson nor Scientific American intended the graph to be completely accurate or claimed it was backed by any research more than that required to estimate the energy costs of moving different kinds of moving things through some distance. It was a graph to make one limited point. More importantly, it illustrates how externalised costs can become counterproductive if attempts to factor them in are not guided by subjective, qualitative assessments of what we’re arguing for or against.
Of course the question of external costs is an important one to ask — more so today, when climate commitments and actions are being reinterpreted in dollar figures and quantitative assessments are gaining in prominence as the carbon budget may well have to be strictly rationed among the world’s countries. But whether or not some activity is rendered more or less efficient by factoring in its externalised costs, any human industrial activities — including those to manufacture bicycles — are polluting. There’s no escaping that. And the struggle to mitigate climate change is a struggle to mitigate climate change while ensuring we don’t undermine or compromise the developmental imperative. Otherwise the struggle isn’t one at all.
Even more importantly, this balancing act isn’t a strategy and isn’t the product of consensus: it’s an implicit and morally and ethically correct assumption, an implicit and inviolable component of global climate mitigation efforts. Put another way, this is how it needs to be. In this milieu, and at a time it’s becoming clear the world’s richer countries have a limit to how much they’re prepared to spend to help poorer countries deal with climate change, the impulse to consider externalised costs can mislead decision-making by making some choices seem more undesirable than they really are.
Externalised costs are, or ought to be, important when the emissions from some activity don’t stack up commensurately with any social, cultural, and/or political advantages they confer as well. These costs are not always unavoidable nor undesirable, and we need to keep an eye on where we’re drawing the line between acceptable and unacceptable costs. The danger is that as richer countries both expect and force poorer ones to make more emissions cuts, the latter may have to adopt more robust quantitative rationales to determine what emissions to cut from which sources and when. Should they include externalised costs, many enterprises that should actually live on may face the axe instead.
For one, the HotB should be able to continue to ride on.
Addendum: Here’s an (extended) excerpt from the Scientific American article on where the HotB scores their efficiency gains.
Before considering these developments in detail it is worth asking why such an apparently simple device as the bicycle should have had such a major effect on the acceleration of technology.The answer surely lies in the sheer humanity of the machine. Its purpose is to make it easier for an individual to move about, and this the bicycle achieves in a way that quite outdoes natural evolution. When one compares the energy consumed in moving a certain distance as a function of body weight for a variety of animals and machines, one finds that an unaided walking man does fairly well (consuming about .75 calorie per gram per kilometer), but he is not as efficient as a horse, a salmon or a jet transport. With the aid of a bicycle, however, the man's energy consumption for a given distance is reduced to about a fifth (roughly .15 calorie per gram per kilometer). Therefore, apart from increasing his unaided speed by a factor of three or four, the cyclist improves his efficiency rating to No. 1 among moving creatures and machines.
… The reason for the high energy efficiency of cycling compared with walking appears to lie mainly in the mode of action of the muscles. … the cyclist … saves energy by sitting, thus relieving his leg muscles of their supporting function and accompanying energy consumption. The only reciprocating parts of his body are his knees and thighs; his feet rotate smoothly at a constant speed and the rest of his body is still. Even the acceleration and deceleration of his legs are achieved efficiently, since the strongest muscles are used almost exclusively; the rising leg does not have to be lifted but is raised by the downward thrust of the other leg. The back muscles must be used to support the trunk, but the arms can also help to do this, resulting (in the normal cycling attitude) in a little residual strain on the hands and arms.
