There is a lot of good writing on the precautionary principle appearing in academic journals. I should know, I am asked to peer review a lot of it. But there is one consistent mistake made in these articles. The authors focus their attention (and angst) on the definition of the precautionary principle. Many critics of precaution declare that all the different definitions of the principle render it meaningless or incomprehensible. What the critics and supporters of the principle miss when they limit their attention to the definition is that the precautionary principle is not self-implementing. There is nothing in the definition that tells you how to carry it out.
The two most commons definitions are the Rio Declaration and the Wingspread Definition. They are as follows:
Rio Declaration Principle 15
In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.
When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically.
There are clear differences between these two definitions and the many others that are part of treaties, laws and policies around the world. Rio is stated passively and negatively: uncertainty shouldn’t be a reason to block action. Wingspread is stated actively and positively: precautionary measures should be taken when an activity raises threats of harm.
No matter what the differences are in the definitions, every single definition contains the same three elements—threats of harm, uncertainty and precautionary action. The beauty and power of the precautionary principle is that it is under-determined and fractal. By this I mean that it can apply to any environmental or public health issue and it can apply at any scale–from GMOs to nuclear power to climate change and from the international scale to choices made in your own home. But the fact that it is under-determined is what gives most critics heartburn. The definitions don’t tell you what to do.
I was one of the conveners of the Wingspread Conference in 1998, which was held specifically to design the steps to implement the precautionary principle. Over the past 13+ years we’ve identified 5 key elements to precautionary action. They are: heeding early warnings, setting goals, identifying and choosing the best alternatives, reversing the burden of proof, and engaging all stakeholders in democratic decision-making.
These steps are complete enough that they provide clear guidance to decision-makers. After all of these years and all the experiments with the precautionary principle, it is clear that we can stop arguing about the definitions and get on with the real work of taking precautionary action to prevent harm even when the science is uncertain.