A History of Scientific Alarms

Article excerpt

Dr Kesten Green lists the 20 most unscientific scares.

There is a long and dismal history of alarming forecasts that were literally too bad to be true. But many people believed these predictions that human actions would harm the environment and thereby cause disaster for people. As early as 1798, Thomas Malthus predicted that the human population would grow beyond the ability of the environment to support it. Before him, Socrates bemoaned the loss of forests around Athens. Arguably the most harmful alarm was about DDT, the banning of which has cost many millions of lives.

The alarms were based on forecasts, but not ones from proper scientific forecasting methods. The alarmists make their alarming forecasts in three broad ways: by using unrealistic mathematical models, such as Malthus'; by extrapolating the genuine effect of a large dose to a near-zero dose; and by hypothesising that a weak effect exists and extrapolating that it will become important over time or over a large population. The third of these unscientific forecasting methods is the one most favoured by alarmists.

Because the alarmists fail to use proper forecasting methods, there is no reason to expect their alarming forecasts to be accurate, except by chance. The unscientific methods that alarmists use are biased towards making alarming forecasts. Most of the alarmists' forecasts were categorically wrong. The rest were wrong in degree: the effects the alarmists were concerned about turned out to be too trivial to cause problems.

The media are culpable in promulgating these false alarms. Though regrettable, the weakness is understandable: alarms are news. …