Climate Change and the Non-Sensical Precautionary Principle

Thom Lambert —  11 December 2009

In his New York Times column, Thomas Friedman advocates “doing the Cheney-thing on climate — preparing for 1%.” He’s referring to Vice-President Cheney’s reported remark: “If there’s a 1% chance that Pakistani scientists are helping Al Qaeda build or develop a nuclear weapon, we have to treat it as a certainty in terms of our response.”

This 1% doctrine, Friedman contends, is really just a restatement of the well-known and highly influential precautionary principle. In its most famous recitation, that principle states: “When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically.” In other words, “It’s better to be safe than sorry.”

The problem with the precautionary principle is that it’s literally non-sensical. It says, “If there’s a course of action that involves threats of harm to human health or the environment, take precautions against it.” The problem is that precaution-taking itself threatens harm to human health and the environment. When we devote resources to avoiding one risk, we divert those resources from some other welfare-enhancing use. When we turn away from a cheap risk-creating technology to a more expensive technology that creates less direct risk, we raise the price of the technology and of any goods or services the technology produces. Poor people will be even poorer. And poverty creates grave threats to human health and the environment.

Thus, it’s not enough to look only at the benefit side of precaution-taking. Because tradeoffs are inevitable, we should also consider the costs of precautions against anthropogenic global warming. In a series of Wall Street Journal op-eds, Bjorn Lomborg has detailed some of those costs: less money for sea walls, storm warning systems, and solidly constructed homes in India and Bangladesh; less money for food, medical treatment, and HIV drugs in Ethiopia; less money for fighting malaria in Zambia; less money for schooling and transportation in Vanuatu.

Now it may be worth incurring these costs in order to reduce the risks of anthropogenic global warming. But Friedman’s precautionary principle can’t tell us that. In saying, “Err on the side of precaution-taking,” it gives literally no direction. A far more helpful principle would balance the expected benefits of carbon caps against their very substantial costs (including, of course, the higher costs of heating and cooling this vulgar monstrosity).

Thom Lambert


I am a law professor at the University of Missouri Law School. I teach antitrust law, business organizations, and contracts. My scholarship focuses on regulatory theory, with a particular emphasis on antitrust.