Environmental effects tend to be gradual, invisible and complex - in other words, not exactly suited for everyday language. A traditional use of the word "price" doesn't cover all the interrelated environmental costs that go into, say, a piece of fruit at your local supermarket. The term "natural resources" doesn't bring to mind all the value that functioning ecosystems provide.
Developing appropriate language for these concepts is an active and important field. Some of these new environmental terms have become widespread cognitive metaphors that deeply affect the way people think about their daily lives. Others have yet to catch on. Some of them even contradict each other - particularly ones that meld ecology with economics. For instance:
The image of the carbon footprint is successful, valuable, and, rhetorically, pretty odd.
"Footprint" hasn't always been used to mean "occupied space" (William Safire's "On Language" column in the New York Times has a good comprehensive overview of the word's evolution) and the concept of a specifically "ecological" footprint is even more recent. The father of this footprint is ecological economist William Rees. Starting in 1992, Rees wrote a series of papers with then-graduate student Mathis Wackernagel using the concept of an ecological footprint, defined informally as "the land that would be required now on this planet to support [a population's] current lifestyle forever."
Since then, the concept has taken off as a teaching and policy tool at institutes like Wackernagel's own Global Footprint Network, devoted entirely to footprint-based ecological accounting. But, as the Network points out on its website, the more specific carbon footprint has taken on a life of its own.
The original purpose of the footprint approach was to point out the limits to human economic expansion: namely, the fact that Earth only had so much land. By visualizing resource consumption as the land area necessary to support that consumption, Rees and Wackernagel made the point that current human habits required more than one Earth to be sustainable. Functionally, this approach was a snazzier way of discussing the planet's carrying capacity, a topic discussed for years by researchers like Paul Ehrlich, Gretchen Daily, and Peter Vitousek.
But, as it's commonly used, a "carbon footprint" is simply the total amount of carbon produced by an entity. This concept is now a fundamental policy tool, a household phrase, and a good example of what sociologist Alastair Iles calls a "missing object" – an abstract or dispersed effect that's bundled into something concrete.
That said, the carbon footprint isn't a footprint at all. No land is involved (although the Global Footprint Network still uses carbon footprint to refer to the land required to sequester carbon dioxide emissions). The term "carbon footprint" doesn't even hint at the built-in upper limit that the ecological footprint was originally meant to emphasize. This shift is particularly obvious when you look at its incorporation into ideas like Green Growth – which we will look at next week, when we return with the next article in this series.