1. The Precautionary Principle and Cost-Benefit analysis
Risk Assessment
The Precautionary Principle
and
Cost-Benefit analysis

2. The Precautionary Principle
“Better safe than sorry”
“Always err on the safe side”
More formally (and more controversially):
“The lack of complete certainty is not a justification to do nothing.”
If there is a reasonable suspicion of harm, AND …
there is scientific uncertainty about cause and effect THEN …
We have a duty to take action to prevent the potential harm.
Burden of proof is on those who claim there is no risk.
(from the Science and Environmental Health Network)

3. Applied to Global Warming
“The lack of complete certainty is not a justification to do nothing.”
Is there is a reasonable suspicion of harm?
Is there scientific uncertainty about cause and effect ?
Do we have a duty to take action to prevent the harm?
Are there downsides to consider if we “overreact” to a non-crisis?
We’ll get back to this VERY complex example later.

4. Simpler Examples of P.P. Tobacco and Lung Cancer Second-hand smoke
X-rays and Cancer
Cell phones and Cancer
Lead in paint, lead additive in gasoline
Asbestos removal laws
Sweetener bans
Food recalls (spinach, tomato, beef this year)
Speed limits
Carbon monoxide detector laws
Helmet laws (minors, bicycles, cars … )

5. The Costs of Precaution
Economic effects (Ex: of asbestos abatement)
increased cost to producers
job losses as employers layoff to cut costs
increased prices to consumers
businesses MUST profit to stay in business
Quality of life issues (Ex: CAFE standards)
We could ban lead and mercury, but at what loss?
Better use for the resources ($) (Ex: CO detectors)
How many lives do carbon monoxide detectors save?
Could those millions be better spent in cancer research, …?
My wife is far more likely to die of breast cancer than CO poisoning
Unintended consequences (Ex: DDT and malaria)
Must weigh Costs against the Benefits

6. Acceptable Levels of Risk
Is a zero-risk life possible?
don’t bungee-jump
don’t smoke
don’t drink alcohol
don’t eat unhealthy foods
don’t drive
don’t have sex
If not, how do we determine the acceptable risk level?

7. Cost–Benefit Analysis
Applying the financial analysis technique to policy making and personal decision-making
A more complicated alternative to the Precautionary Principle
Example: Cost-Benefit analysis of eliminating cell phones, which may produce dangerous radiation.

8. Reacting to Global Warming
What is the main cause of anthropogenic GW?
What must be done to reduce our contribution to GW, assuming there is one?
What are the costs of doing the above?