“One Person, One Share” of the Atmosphere

For most of human existence, people living only short distances apart might as well have been living in separate worlds. A river, a mountain range, a stretch of forest or desert: these were enough to cut people off from each other.

As a result, our moral intuitions evolved to deal with problems within our community, rather than with the impact of our actions on those far away. Resources like the atmosphere and the oceans seemed unlimited, and we have had no inhibitions against making the fullest use of them.

Over the past few centuries the isolation has dwindled, and now people living on opposite sides of the world are linked in ways previously unimaginable. Problems like climate change have revealed that by driving your car, you could be releasing carbon dioxide that is part of a causal chain leading to lethal floods in Bangladesh.

How can our ethics take account of this new situation?

“Enough and as Good”
Imagine that we live in a village in which everyone puts their wastes down a giant sink. The capacity of the sink to dispose of our wastes seems limitless, and as long as that situation continues, it is reasonable to believe that we are leaving “enough and as good” for others. No matter how much we pour down the sink, others can do the same.

This phrase “enough and as good” comes from John Locke’s Second Treatise on Civil Government, published in 1690. In that work Locke says that the earth and its contents “belong to mankind in common.” How, then, can there be private property? Because our labor is our own, and hence when we mix our labor with the land and its products, we make them our own. It has this effect, Locke says, as long as our appropriation does not prevent there being “enough and as good left in common for others.”

Locke’s justification of the acquisition of private property is the classic historical account of how property can be legitimately acquired, and it has served as the starting point for more recent discussions.

Now imagine that conditions change, so that the sink’s capacity to carry away our wastes is used to the full. At this point, when we continue to throw our wastes down the sink we are no longer leaving “enough and as good” for others, and hence our right to unchecked waste disposal becomes questionable.

Think of that giant sink as our atmosphere and our wastes as carbon dioxide and other greenhouse gases. Once we have used up the atmosphere’s capacity to absorb our gases without harmful consequences, it has become a finite resource on which various parties have competing claims. The problem is to allocate those claims justly.

Defining Equitable Distribution
During the 2000 U.S. presidential election, when the candidates were asked in a televised debate what they would do about global warming, George W. Bush said:

I’ll tell you one thing I’m not going to do is I’m not going to let the United States carry the burden for cleaning up the world’s air, like the Kyoto treaty would have done. China and India were exempted from that treaty. I think we need to be more even-handed.

As president, Bush frequently repeated this line of reasoning. Indeed, the issue of what constitutes even-handedness, or fairness or equity, is perhaps the greatest hurdle to international action on climate change. But was Bush right to say that it is not even-handed to expect the United States to restrict its emissions before China and India begin to restrict theirs?

There are various principles that people use to judge what is fair or even-handed. In political philosophy, it is common to follow Robert Nozick, who distinguished between historical principles and time-slice principles.

A historical principle is one that says: To understand whether a given distribution of goods is just or unjust, we must ask how the situation came about; we must know its history. Are the parties entitled, by an originally justifiable acquisition and a chain of legitimate transfers, to the holdings they now have? If so, the present distribution is just. If not, rectification or compensation will be needed to produce a just distribution.

Looking at data for 1900 to 1999, we find that the United States, for example, with about 5 percent of the world’s population, was responsible for about 30 percent of carbon dioxide emissions from fossil fuels, the primary source of greenhouse gases.  Most of this carbon dioxide is still up in the atmosphere, contributing to global warming.

In this case, the application of the historical principle might be called “the polluter pays” or “you broke it you fix it.” It would assign responsibility proportionate to the amount that each country has contributed, a view that puts a heavy burden on the developed nations.

In their defense, it might be argued that at the time when the developed nations contributed most of their greenhouse gases into the atmosphere, they could not know of its limits in absorbing those gases. It would therefore be fairer to make a fresh start now and set standards that look to the future, rather than to the past.

This is the idea behind the time-slice principle. It looks at the existing distribution at a particular moment in time and asks whether that distribution satisfies some idea of fairness – irrespective of any preceding sequence of events.

An Equal Share for Everyone
If we begin by asking, “Why should anyone have a greater claim to part of the global atmospheric sink than any other?” then the first, and simplest response is: “No reason at all.” Everyone has the same claim to part of the atmospheric sink as everyone else. This kind of equality seems self-evidently fair, at least as a starting point for discussion.

The Kyoto Protocol aimed to achieve a level for developed nations that was 5 percent below 1990 levels. Suppose that we focus on emissions for the entire planet and aim just to stabilize them. If we choose a target of 1996 emissions levels, then the allocation per person works out conveniently to about 1 metric ton of carbon per year. This becomes the basic equitable entitlement for every human being on the planet.  (Note that emissions are sometimes expressed in terms of tons of carbon dioxide, rather than tons of carbon. One ton of carbon is equivalent to 3.7 tons of carbon dioxide.)

Now compare actual emissions for some key nations. In 2004, the United States produced 5.61 tons of carbon per person per year, while Japan, Germany and the U.K. each produced less than 3 tons. China was at 1.05 and India at 0.34. This means that to reach an equal per capita annual emission limit of 1 ton, India would be able to increase its emissions three times. China, on the other hand, would need to stabilize its current emissions, and the United States would have to reduce its emissions to one-fifth of present levels.

One objection to this approach is that it gives countries an insufficient incentive to do anything about population growth. We can meet this objection by setting national allocations that are tied to a specified population, rather than letting them rise with an increase in population.

But since different countries have different proportions of young people about to reach reproductive age, this provision might produce greater hardship in countries that have younger populations. To overcome this, the per capita allocation could be based on an estimate of a country’s population at some future date. Countries would then receive a reward in terms of an increased emission quota per citizen if they achieved a lower population than had been expected.

A Proposal
Each of these principles of fairness, or others, could be defended as the best one to take. I propose, both because of its simplicity, and hence its suitability as a political compromise, and because it seems likely to increase global welfare, that we support the principle of equal per capita shares of the capacity of the atmospheric sink, tied to the current projections of population growth per country for 2050.

Some will say that this is excessively harsh on industrialized nations, which will have to cut back the most on their output of greenhouse gases. Yet the one person, one share principle is more indulgent to the industrialized nations than some other others, including the historical principle.

Allocating on the basis of equal per capita shares will be tremendously dislocating for the industrialized nations, and the mechanism of emissions trading can make this transition much easier. Emissions trading works on a simple economic principle: If you can buy something more cheaply than you can produce it yourself, you are better off buying it than making it. In this case, what you can buy will be a transferable quota to produce greenhouse gases, allocated on the basis of an equal per capita share.

Appropriate Scale
The ancient Greek iconoclast Diogenes, when asked what country he came from, is said to have replied: “I am a citizen of the world.” Until recently, such thoughts have been the dreams of idealists. But now we are beginning to live in a global community. The impact of human activity on our atmosphere exemplifies the need for human beings to act globally. On this issue, as well as others, the planet should become the basic unit for our ethical thinking.
 

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