The Worldwide Fund for Nature (WWF) has devised a measure of the impact that a given country has on the planet's environment. They call this the country's ‘ecological footprint’ and they report it in units of area. It is the area of the Earth that could notionally produce the resources in question (for example, forests could convert atmospheric carbon dioxide back into trees at a certain rate per unit area). The metaphor there is that the planet has only a fixed area. So if we use it up, some of us are going to have to be ejected through Spaceship Earth's metaphorical airlock. At present,
each person needs 2.2 global hectares to support the demands they place on the environment, but the planet is only able to meet consumption levels of 1.8 global hectares per person
So we are overdrawing our ecological account. Soon we shall need two planets, they say.
Using the WWF's annual report on these issues, the BBC report cited above includes a chart showing the ecological footprint per capita of a few selected countries, essentially as follows:
As you can see, the huge boots of Americans, Australians and Britons are trampling over the world's bio-space, while poor but virtuous Sierra Leoneans and Afghanis are treading lightly on the Earth's sacred resources. It seems obvious who most deserves to be kicked off the planet.
But does this measure make sense?
First off, we're not at all sure that the measures of ‘footprint’ themselves are accurate. The data are hard to collect and harder to interpret, and many assumptions had to be made. For example, 48% of the footprint is currently due to carbon dioxide emissions. So if you think that the global warming problem might be solved, you will have to reduce most of the footprint estimates. And so on. But never mind all that. Even on the assumption that their footprint measure is accurate, dividing it by a country's population is of doubtful value. For example, if a country doubles its population without doubling its productivity, its real impact on the environment will increase, but its impact per capita will go down. The country will count as more environmentally virtuous – smaller ecological footprint per capita – by virtue of its runaway overpopulation! Conversely, a country that uses resources very efficiently may still count as becoming more environmentally unfriendly (larger footprint per capita) solely because it has also achieved low population growth.
This is the wrong way round. A better measure of environmental virtue would be the ecological footprint per unit GDP. This does not allow countries to ‘cheat’ by merely increasing their population without changing their physical effect on the environment, but it does take account of whether a country is wasting resources or using them efficiently. Out of curiosity, we used the WWF's numbers and the BBC's countries to construct the appropriate chart:
The countries are now in approximately the opposite order. Notice that the United States goes from worst on the chart, to using less than capacity, even though the worldwide average is 125% of capacity. This isn't a coincidence. Western countries create their ‘footprint’ as part of their productive process – creating the very things that let us lower the footprint while also increasing human welfare.
Footprint-per-GDP is, in our opinion, a better measure of countries' environmental virtue. And it does not even take account of the other huge factor that is missing from the WWF's analysis: the ‘area’ (real or metaphorical) needed to sustain one person is not a constant of nature but depends on the available technology. For instance, how well the Earth can recover depends in part on how many carbon-dioxide-fixing machines we can build, and how efficiently, which in turn depends on how much wealth we can create and how fast. And hence the developed countries, the villains of the piece according to the environmentalists' narrative, are in reality even more environmentally virtuous even by the WWF's standards of ‘impact’ than our chart makes them seem.
(Data collected by Elliot Temple.)