This book develops a theory of how states can cooperate in protecting their shared environmental resources—resources like the ozone layer, the blue fin tuna, the Aral Sea, the entirety of the earth's biodiversity, and the global climate. The book explains why international treaties are the primary means for doing this, and why, if they are to succeed, treaties must strategically manipulate the incentives states have to exploit the environment.
Though the issues of concern to this book are very real, they are as much a conceptual as a practical challenge. It is not even easy to tell whether a particular treaty succeeds in protecting the environment. For we see only one thing: a world in which the treaty exists. To know whether the treaty has succeeded we would need to see more. We would need to know what would have happened had the treaty never existed. And we would need to know what would have happened in an idealized world, where states were unhampered by the constraint of sovereignty. These benchmark outcomes cannot be observed. They must instead be inferred. Such inferences, however, must be arrived at systematically. We need to structure our imaginations, and this is why we need a theory.
Indeed, a theory can do even more than evaluate a given treaty. It can tell us how we might write better treaties, agreements that really do improve the way we manage our shared environmental resources. A key aim of this book is to show how we might do this.
Transnational environmental problems are much harder to remedy than the domestic variety because of the principle of sovereignty. Under the rules of international law, states can pretty much act as they like, and there is no World Government, no Global Environmental Protection Agency, that can make states act differently. And yet, if all states acted just as they pleased, the consequences may well be awful all around. There may be no check on the amount of greenhouse gases emitted into the atmosphere, no restraint on the logging of unique rainforests, no easing in the pace of over-fishing. To do better, we have to restructure the incentive system. This is what treaties are meant to do.
Unfortunately, most treaties—and I list or discuss over 300 treaties in this book—fail to alter state behavior appreciably. The great exception to this rule is the Montreal Protocol on Substances that Deplete the Ozone Layer, and I use the theory to explain how and why this agreement succeeded. My view is that you cannot understand the more common failures of international cooperation until you have understood the reasons for Montreal's success.
I have heard many people say that the reasons for Montreal's success are obvious. Some are. But others are camouflaged, and analysis of this treaty, like others, requires a certain forbearance. To make sense of this problem requires breaking it down into