Passive smoke risk is often used in the climate change debate to illustrate how the tobacco industry used false representations of "doubt" in attempt to save their industry and billions of dollars at risk. This leads to how the Big Oil companies must be doing the same thing since they are trying to preserve their businesses and avoid trillions of dollars of risk. Some say the comparisons are unfounded, some live by them. What's an outsider to do?
First, recognize that the comparisons have a great deal of validity. Valid comparisons cut both ways, though. Let's see how.
Passive smoke studies were primarily based on a male head of household and female non-smoking spouse with children. that was a fairly average family structure at the time the surveys began, dad smoked, mom and the kids didn't. The studies found that the non-smoking family members had a greater risk than the average non-smoking population. Various studies determined varying degrees of risk associated with passive smoke in the home. Similar work place studies were done, all indicated a general increase in lung cancer risk plus some other varieties of cancers. Passive smoke is definitely linked to health issues in non-smokers. For the sake of simplicity, I am only going to use the lung cancer risk.
Passive smoking increases the risk of lung cancer in non-smokers by 30% is the standard argument of the no smoking crowd. It is perfectly correct, but what does it really mean?
Non-smoking individuals with prolonged exposure to passive smoke have a 30% great risk than the general non-smoking population, which has a 1.3% risk of developing lung cancer over their lifetime, all things remaining equal. So non-smokers in a smoking household have a 30% greater risk than the general population, 1.3%, meaning they have a 1.69% risk of lung cancer. 30% greater than 1.3 is 1.69. What if all things don't remain equal?
If a concerned smoker in a non-smoking household changed their smoking habits around the non-smokers, the risk changes. Installing a special smoke filtering system reduces risk. Improving the ventilation of the smoking spaces or the non-smoking spaces reduces risk. Knowing that there is an increased risk, the smoker can reduce the risk for his family. Life is not static, all things rarely remain equal.
In climate change, a doubling of CO2 will cause about 1.5 degrees of warming, all things remaining equal. If water vapor is a positive feed back to the CO2 increase, the doubling of CO2 can cause 4.5 degrees of warming. If other factors provide positive feed back to increase of CO2, more warming is possible, all other things remaining equal.
So the premise of both arguments is the same, something may happen if nothing changes. There is a fancy term for this type of reasoning, I am not fancy, so I use the term "bullshit" reasoning.
Having worked in the Heating, Ventilation and Air Conditioning industry, I know how things can be changed to reduce risk of harm from tobacco smoke and dozens of other hazardous indoor air pollutants. Prior to the bans on workplace smoking, the HVAC industry and building owners invested a great deal of time and money improving indoor air quality. A condition termed, Tight Building Syndrome was commonly used for well insulated and seal buildings that had various occupants with various health issues due to poor air quality inside the higher energy efficient buildings.
Outside Air: Prior to improved building insulation and "wrapping" methods, the average building was drafty. Outside air came into the buildings through windows that once were capable of being opened, ventilated attic spaces and generally not well sealed doors, walls, ceiling and floors. This provided fresh outside air to dilute the indoor air which tended to accumulate odors from various sources. To reduce the problem of less air leakage, outside air was forced into the tight buildings through air conditioning units.
VOCs: Volatile Organic Compounds in the conditioned spaces of homes and workplaces increased with technology following World War II. Plastics, paints, cosmetics, insecticides, nearly all new products for the home had some chemical produced to make things last longer, smell better, taste better or look neater, than before. Tight buildings increased the concentration of these VOCs in the home and workplace. Many VOCs cause health risks including lung cancer.
Molds: The increased use of air conditioning created its own indoor air quality problems by providing ideal conditions for the growth of molds, mildew, fungus etc. in side the living spaces and workplaces. Because of water condensing on cooling coils, dust collected in air conditioning units and duct work, and the dark conditions, food, water and shelter was provided for the worst culprit of poor indoor air quality, molds.
The improvements in life added risk of various health issues in the home. With the studies comparing risks of one generation with a future generation, a primary cause for health issues, including lung cancers, may not have been considered. Changes in HVAC systems to reduce indoor air quality issues were not considered. All things did not remain equal.
Few things in life remain equal. Is it reasonable to expect that all things will remain equal in our climate? Most rational people do not believe that all things will remain equal. They would like to know the impact of things that do change, on the predictions if things do not change. That is not being a merchant of doubt, that is recognizing change and uncertainty, major factors in making informed decisions.