Baseless panics and consensus opinions

An interesting exercise in Global Warming Analogies Forecasting Project by J. Scott Armstrong and Kesten C. Green. In the context of the sustained IPCC alarm over global warming, the researchers ask,

Have there been other situations that involved widespread alarm over predictions of serious harm that could only be averted at considerable cost? We are particularly interested in alarms endorsed by experts and accepted as serious by relevant authorities.”

Here is the list Armstrong and Green compiled of analogous scares. An interesting mix. Just eyeballing the list without any research (and omitting the first couple from 1798 and 1865), some I just don't know enough about to judge the status (6), some weren't issues at all or the impact was much less than anticipated (14), and some really were significant (4).

Analogies to the alarm over dangerous manmade global warming

1 Population growth and famine (Malthus) 1798
2 Timber famine economic threat 1865
3 Uncontrolled reproduction and degeneration (Eugenics) 1883
4 Lead in petrol and brain and organ damage 1928
5 Soil erosion agricultural production threat 1934
6 Asbestos and lung disease 1939
7 Fluoride in drinking water health effects 1945
8 DDT and cancer 1962
9 Population growth and famine (Ehrlich) 1968
10 Global cooling; through to 1975 1970
11 Supersonic airliners, the ozone hole, and skin cancer, etc. 1970
12 Environmental tobacco smoke health effects 1971
13 Population growth and famine (Meadows) 1972
14 Industrial production and acid rain 1974
15 Organophosphate pesticide poisoning 1976
16 Electrical wiring and cancer, etc. 1979
17 CFCs, the ozone hole, and skin cancer, etc. 1985
18 Listeria in cheese 1985
19 Radon in homes and lung cancer 1985
20 Salmonella in eggs 1988
21 Environmental toxins and breast cancer 1990
22 Mad cow disease (BSE) 1996
23 Dioxin in Belgian poultry 1999
24 Mercury in fish effect on nervous system development, 1; 2 2004
25 Mercury in childhood inoculations and autism 2005
26 Cell phone towers and cancer, etc. 2008

It is great when you deal with concrete examples rather than abstractions because it forces much greater nuance and understanding. For example, take Mad Cow Disease. I was in Britain when that first came to public attention and the panic was palpable as people realized just how long the incubation period was and how big the numbers might get in terms of people who might fall prey to it. As it turned out, the disease was real and I would argue that during the longish period of uncertainty, people were right to be concerned, but in the event, the population affected turned out to be very small.

The net is that more than half the sample panics turned out not to be real or turned out to be far smaller in scale than initial expert forecasts anticipated. Some of those panics that turned out not to be real (DDT and cancer, possibly acid rain, possibly BSE, etc.) had very large real-world costs in lives and money when they were acted on with conviction but not validity.

This is very much a work in progress with much potential disputation. However, it is a useful reminder that many beliefs held with conviction or forecasts made with certainty are faith-based assumptions and not fact-based consensus.