Environmental fears shouldn’t be our only guide in creating city policy.

Ten years ago, when the other George Bush was president, the 1992 Rio Declaration on the Environment and Development produced a doctrine known as the “precautionary principle,” which some want San Francisco to adopt as a basis for public policy. That would be an unwise move for a number of reasons.

The precautionary principle states that a lack of full scientific certainty shall not be used as a reason for postponing action to protect the environment. In other words, even if we don’t have the facts, the government should still take drastic measures as a first resort when it comes to protecting the environment.

Last year the Planning and Policy Committee of the San Francisco Commission on the Environment considered a resolution urging that the city adopt the precautionary principle “as a guide for all public and private sector policies, decisions, and activities.”

The result is a game of risk: the risks of introducing a new technology are weighed heavily while the risks of not introducing the technology are ignored. For example, pristine water and untouched land are two aspirations near and dear to San Franciscans. However, with an increasing population, agriculture threatens to divert more water and land for its uses. Biotechnology promises not only to increase agricultural yields to feed and clothe a growing population, but also to reduce the amount of land and water used to grow crops. This technology would be banned under the precautionary principle just because some of the risks are unknown.

The goal of the precautionary principle is to induce caution and prevention in the face of unknown risk. While this sounds perfectly reasonable, the principle carries risks of its own. For starters, deliberate disregard of science is hardly a reliable guide for public policy. Further, power corrupts, and public officials always need careful monitoring.

Few strategies can carry more risk than using environmental fears as an excuse to give officials new and sweeping powers to take drastic action on “all public and private sector policies.” That is particularly true when the record of environmental scaremongers sometimes invoked by public officials is not exactly inspiring.

Consider, for example, Stanford’s Paul Ehrlich, author of The Population Bomb (1968), a book that helped launch the modern environmental movement. Ehrlich predicted that, because of pesticides, life expectancy in the United States would drop to 42 by 1980, when the U.S. population, he said, would be reduced to 22.6 million. The mass starvation and depletion of resources he predicted also failed to take place.

Likewise, the Alar scare needlessly terrified millions of people. Electric transmission and cellular phones do not, as some have charged, cause cancer. Doomsaying based on the superstitions of junk science, as Michael Fumento has shown, is a veritable growth industry.

No principle can alter the hard reality that the world is a risky place. Living in San Francisco, a proven earthquake zone, is risky. Driving on I-80 during rush hour is risky, as is riding a bicycle on city streets and eating in certain San Francisco restaurants. Lighting and heating our homes and disposing of wastes also entail risk. In a world of limitations, actual risks must take priority over potential risk.

A chilling effect on technological innovation is another likely consequence of the precautionary principle. Technology has played a role in producing a cleaner environment. But the precautionary principle does not allow for a full assessment of alternative technologies. In fact, by its nature the precautionary principle stifles innovation, in the name of avoiding potential risks. For example, nuclear power plants may ultimately do less environmental damage than fossil fuel power plants, but fears surrounding nuclear plants prevent a full exploration of their potential.

New technologies, including those that make for a cleaner environment, seldom appear overnight. They require extended research and development. But under the precautionary principle, they could be quashed if their first efforts do not achieve perfection.

Every day brings reminders that perfection is not attainable in public life or anywhere else. Therefore, sacrificing the good for the perfect, which the precautionary principle does, is no basis for public policy.

Responsible public policy rejects fearmongering, realizes the inevitability of tradeoffs, and carefully considers the best science before taking action. When assessing risk, responsible policymakers will weigh the relative benefits of new technology. Ten years after the Rio Declaration, those are precautionary principles worth considering for San Francisco, California, and the nation.

Examiner columnist Sally Pipes is the President and CEO of the Pacific Research Institute, a California-based think tank. She can be reached via email at spipes@pacificresearch.org.