Warnings too vivid to be true

By Kesten Green


Roughly one person in two is concerned about man-made global warming. Why? Because vivid, alarming forecasts are persuasive … for a time.

Take the alarm over mercury in fish. In 2004, the U.S. Environmental Protection Agency warned that each year 630,000 babies were born at risk of brain and nervous system damage because of “unsafe” levels of mercury in their mothers’ blood.

It turns out that “at risk” meant having concentrations of mercury in the blood that were higher than unjustifiably low levels. Japanese consume a lot of fish and those “at risk” levels are exceeded by 74 percent of Japanese women of childbearing age. Yet, there is no evidence that Japanese are mentally deficient. Only health benefits have been confirmed from high levels of fish consumption.

The alarming forecast of harm from mercury in fish was derived by extrapolating known bad effects from high doses of mercury to predict toxic effects from even very low levels, without bothering to check for evidence. Bad alarm.

With my colleague Scott Armstrong and suggestions from diverse experts, I identified 26 alarms that are analogous to the dangerous man-made global warming alarm. You can find them on the publicpolicy website.

All of the alarms turned out to be false, either completely or to such an extent that actions intended to be remedial caused much greater harm than the supposed problem.

When alarming forecasts are presented in the form of vivid scenarios, people tend to ignore the low likelihood that they will come to pass. They want action.

Today, when we are safer than we have ever been, clever and creative people become rich and famous by exploiting the public and media weakness for alarming scenarios.

Policy responses to the global warming and other environmental alarms are promoted in terms of social causes such as “caring for the planet” or “caring for our children,” which has the intended effect of deflecting hard questions about the substance of these claims, and of demonizing people who ask them.

It isn’t immediately obvious that beneath the caring veneer are people who stand to gain from promoting the alarm, by advancing their careers and fortunes.

As have other environmental alarms before it, the dangerous man-made global warming alarm will fade. Unfortunately, policies that make most people worse off have and will be implemented. We would be better off if we didn’t keep repeating the same old mistakes.Forecasting expert Kesten Green is a senior lecturer and senior research associate at the University of South Australia in Adelaide. Comments:

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