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Past Alarmism and the Future of Manmade Global Warming

Polls show that roughly one person in two is concerned about manmade global warming. Why? Because vivid, alarming forecasts, even those based on weak foundations, are persuasive. For a while at least.

We've seen this many times before. Take the alarm over mercury in fish: in 2004, an Environmental Protection Agency employee warned that 630,000 babies per year were born at risk of brain and nervous system damage due to "unsafe" levels of mercury in their mothers' blood. Expectant mothers were discouraged from eating fish.

Japan consumes a lot of fish, and the supposedly unsafe levels cited by the EPA are exceeded by 74% of women of childbearing age there. Yet there is no evidence that their children are mentally deficient. In fact, only benefits have been reported from high levels of fish consumption, including good brain function and improved intelligence at age four.

The alarming forecast of harm from mercury in fish was derived by extrapolating known bad effects from high doses of mercury to incorrectly predict toxic effects from even very low levels -- without bothering to check for evidence. This poorly founded forecast resulted in mothers and their children avoiding a healthy food, to their detriment.

Working with Professor J. Scott Armstrong of the University of Pennsylvania and others, Dr. Kesten Green identified 26 previous alarms that are analogous to the dangerous manmade global warming scare. Besides the alarm over mercury, the 26 alarms include familiar ones like electromagnetic fields (EMF) and cancer, and DDT and cancer.

A 1979 American Journal of Epidemiology article linked exposure to weak EMF from electrical wiring with childhood leukemia. Media and scientists followed, making shrill claims of widespread and diverse harm including headaches and depression. In response, the U.S. government adopted exposure limits and other regulations that World Health Organization researchers estimated impose a $1 billion annual cost on the economy.

But the authors of the journal article that raised the alarm did not actually measure exposure to EMF. Tens of thousands of articles have been published since, and the conclusion is that there is no link between weak EMF and human health.

Rachel Carson raised alarm over the insecticide DDT in her 1962 book Silent Spring, claiming that it caused cancer. There was no good evidence for this assertion, and there still isn't. The EPA nevertheless banned DDT in 1972, and Europe and Africa, under pressure from international agencies, followed. The main consequence of the ban is that millions of people have died needlessly from mosquito-borne diseases such as malaria.

All of the analogous 26 alarms analyzed by Green and Armstrong turned out to be false, either completely or to such an extent that actions intended to be remedial caused greater harm than the supposed problem. See www.PublicPolicyForecasting.com for descriptions of some of the other 26 analogies: because media report alarms enthusiastically but not their demise, many readers will be surprised to find that alarms they still believe to be true have now been debunked.

When alarming forecasts are presented in the form of vivid scenarios, many people ignore the low likelihood that they will come about: they want action. This is especially so if they think the cost of action will be low (to themselves), and they can blame others.

Policy responses to environmental alarms are often promoted in terms of "caring for the planet" or "caring for our children." This has the intended effect of deflecting questions about the substance of alarming claims, and of demonizing those who ask them.

In modern times, when we are safer than we have ever been, some activists have become rich and famous by exploiting our ready acceptance of alarming scenarios: "So we have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have." This statement about global warming by climatologist Professor Stephen Schneider (now deceased) serves as a warning to us all that we should always be ready to ask hard questions of alarmists.

Although the costs of trying to "stop climate change" are diffused across many people and over time, the public is gradually waking up to the fact that they are already bearing a substantial burden as a consequence of climate policies. As these costs rise, people will increasingly demand hard evidence that their sacrifices are worthwhile and are not merely based on sentimentalism and opportunism.

When people learn more about an issue, the persuasion formula that initially worked so well for alarmists breaks down. People become less persuaded by appeals to trust the authorities, less susceptible to fear, less willing to accept emotional appeals from celebrities, less gullible. Trends in polls show that this is already happening with the global warming scare.

Alarming forecasts of humans harming themselves and the environment by their actions are a common social phenomenon. They become widely believed for a time, cause unnecessary anxiety, and result in costly government policies, then fade from public attention as it becomes more difficult to maintain the alarm in the face of counter-evidence and closer public scrutiny. We hope that this phenomenon of false environmental alarms will become widely recognized so that in the future we can avoid the very real costs that they impose on the most vulnerable people, and then on all of us.