No environmental issue is more polarizing than global climate change. Many on the left fear increases in atmospheric concentrations of greenhouse gases threaten an environmental apocalypse while many on the right believe anthropogenic global warming is much ado about nothing and, at worst, a hoax. Both sides pretend as if the climate policy debate is, first and foremost, about science, rather than policy. This is not so. There is substantial uncertainty about the scope, scale, and consequences of anthropogenic warming, and will be for some time, but this is not sufficient justification for ignoring global warming or pretending that climate change is not a serious problem.
Though my political leanings are most definitely right-of-center, and it would be convenient to believe otherwise, I believe there is sufficient evidence that global warming is a serious environmental concern. I have worked on this issue for twenty years, including a decade at the Competitive Enterprise Institute where I edited this book. I believe human activities have contributed to increases in greenhouse concentrations, and these increases can be expected to produce a gradual increase in global mean temperatures. While substantial uncertainties remain as to the precise consequences of this increase and consequent temperature rise, there is reason to believe many of the effects will be quite negative. Even if some parts of the world were to benefit from a modest temperature increase -- due to, say, a lengthened growing season -- others will almost certainly lose.
Many so-called skeptics note that environmental activists and some climate scientists exaggerate the likely effects of anthropogenic warming, distorting scientific findings and overstating the extent to which contemporary events (hurricanes, etc.) may be linked to human activity to date. But the excesses of climate activists and bad behavior by politically active scientists (and the IPCC) do not, and should not, discredit the underlying science, or justify excoriating those who reach a different conclusion. Indeed, most skeptics within the scientific community readily accept the basic science. They contest the more extreme climate projections, but accept the basic scientific claims. Take, for example, Patrick Michaels of the Cato Institute. In one of his recent books, Climate of Extremes: The Global Warming Science They Don't Want You to Know (co-authored with Robert Balling, another prominent "skeptic"), Michaels readily acknowledges that there is a warming trend and that human activity shares some of the blame.
The position espoused by Michaels, Balling and most (but not all) skeptics is that anthropogenic global warming is occurring, but it is more of a nuisance than a catastrophe. Some even argue that the net effect of climate change on the world will be positive, due to increased growing seasons, less severe winters and the like. Were I a utilitarian, and if I placed substantial faith in such cost-benefit studies, I might find these arguments convincing, but I'm not and I don't. Even if these skeptics are correct that global warming will not be catastrophic and that the net effects in the near-to-medium term might be positive, there are still reasons to act.
Accepting, for the sake of argument, that the skeptics' assessment of the science is correct, global warming will produce effects that should be of concern. Among other things, even a modest increase in global temperature can be expected to produce some degree of sea-level rise, with consequent negative effects on low-lying regions. Michaels and Balling, for instance, have posited a "best guess" that sea levels will rise 5 to 11 inches over the next century. Such an increase in sea levels is likely manageable in wealthy, developed nations, such as the United States. Poorer nations in the developing world, however, will not be so able to adapt to such changes. This is of particular concern because these effects will be most severe in those nations that are both least able to adapt and least responsible for contributing to the concentration of greenhouse gases in the atmosphere.
It is a well established principle in the Anglo-American legal tradition that one does not have the right to use one's own property in a manner that causes harm to one's neighbor. There are common law cases gong back 400 years establishing this principle and international law has long embraced a similar norm. As I argued at length in this paper, if we accept this principle, even non-catastrophic warming should be a serious concern, as even non-catastrophic warming will produce the sorts of consequences that have long been recognized as property rights violations, such as the flooding of the land of others.
My argument is that the same general principles that lead libertarians and conservatives to call for greater protection of property rights should lead them to call for greater attention to the most likely effects of climate change. It is a well recognized principle of common law that if company A is flooding the land of person B, it is irrelevant whether company A generates lots of economic prosperity for the local community (including B). A's action would still violate B's property rights, and B would be entitled to relief of some sort. By the same token, if the land of a farmer in Bangladesh is flooded, due in measurable and provable part to human-induced climate change, why would he be any less entitled to redress than a farmer who has his land flooded by his neighbor's land-use changes? Property rights should not be sacrificed as part of some utilitarian calculus. Libertarians readily accept this principle when government planners violate property rights in the name of economic development (see e.g., Kelo v. New London). Yet they seem to abandon their commitment to property rights when it comes to global warming.