The Precautionary Principle

The Precautionary Principle is a very good principle. It's one of the best protections we have against doing silly things or pursuing courses of action which might have nasty unintended consequences. That doesn't mean that it should be applied to every decision we make about where research should go, or what we manufacture, or how we implement public policy.

For those unfamiliar with the principle, it's basically the "First do no harm" that doctors are supposed to swear by in the Hippocratic Oath. It says that when faced with the decision between two courses of action, we should take the path with the least risk. Sometimes it is difficult to judge or even place a value on relative risks, and this difficulty is exploited by people who like to push a particular agenda.

I'm going to look at three cases where the Precautionary Principle is abused by people who have barrows to push.

The first of these is climate change denial. This is possibly best summed up in a cartoon by Joel Pett which regularly appears in various places on the Internet. It shows someone at a climate change summit asking the question "What if it's a big hoax and we create a better world for nothing?". The argument is that until we are in possession of all the facts about everything that influences climate we should do nothing because the economic cost of doing things is far too great. In reality the correct application of the principle here would be to take steps to reduce the emission of greenhouse gases and the burning of fossil fuels and to increase the reuse and recycling of resources, because even if they have no effect on the climate they will still provide a benefit to society.

Yes, some of the things we might have to do could be immensely disrupting both to the economy and our personal lives. As an example of this, I live in the Blue Mountains west of Sydney and the railway line could not be justified on the basis of passenger traffic alone. It is paid for by the coal which is hauled across it several times an hour in very long trains. In fact the line was only electrified for coal transport, and electric trains to carry people came along a long time later. It has been estimated that in order to limit global warming to no more than 2 degrees about 80% of the coal in Australia has to remain in the ground. Coal is a major export earner for Australia, but the effects of widespread climate change could have a disastrous effect on our other very large export, agriculture. It's a balancing act but that doesn't mean that balance is impossible.

In the worst case scenario, which is the postulated rise of a couple of metres of sea level, we would get a very strong reminder of how close we all live to the coast. We wouldn't be able to export much coal through the world's largest coal port, Newcastle, but as Sydney, Melbourne, Adelaide, Perth, Darwin, and Brisbane would all be awash that might have ceased to be a concern.

The "debate" about climate change is actually a form of Pascal's Wager, where a decision not to do something can have disastrous consequences if we are wrong but if we do something and are wrong the costs and damages could be inconsequential.

A second area where the Precautionary Principle is pointed to to advance an agenda is in alternative "medicine". Opponents of vaccination are always claiming that no vaccine should be used until it can be proved to be 100% both safe and effective. This would mean that there would be no vaccines at all. Similar claims are made for other medicines, and I've been told for example that any death from any cause during a clinical trial shows that a medicine is not safe enough to be released for public use. Ironically the medical fad du jour seems to be medical marijuana where demands are being made for cannabis products to be made available to people with cancer and other diseases in advance of any clinical trials simply because there is a possibility that something might work.

The third example is the opposition to genetically modified organisms. Again the demand is made that absolute safety should be demonstrated before any of these products are released for human consumption. Extremists have even claimed that no research should be done until such research can be proved to be completely safe. I assume such people follow the current food fad of the Paleo Diet and only eat non-hybridised vegetables.

The Precautionary Principle is indeed a very good principle, but we need to apply it recursively to itself to make sure that the precautions taken are what we really need.

This article was published as the Naked Skeptic column in the March 2015 edition of Australasian Science