For years now I’ve seen references to the analogy between the link between tobacco smoking and deaths from lung cancer and the link between the burning of fossil fuels and catastrophic global warming. A common theme is to say something like this: ‘climate change’ deniers are also people who deny that smoking causes lung cancer. Another is to explore the backgrounds of critics of the orthodoxy and argue that they have links to the tobacco industry.
I smoked from 17 to 26 and gave it up to concentrate on sport. I never resumed, and came to detest the smell of cigarettes and their smoke. Australia is immeasurably better for non-smokers than it used to be, and while I had and still have worries about the uniform cigarette-packet laws, I do look forward to the day when no one smokes. I put in this autobiographical stuff because anyone who departs from the orthodoxy in this area is likely to be labelled a denier too.
Having said all that, the assumption that the two links are comparable, even the same, seems to me quite fatuous. Let’s start with smoking. About 80 to 90 per cent of those diagnosed with lung cancer are smokers, and between 10 to 15 per cent are not. Not only that, the more cigarettes smoked the greater the risk of lung cancer. A smoker is about nine times more likely to die of lung cancer than a non-smoker. So the relationship is probabilistic, not direct. Some who smoke won’t die of lung cancer, and some who have never smoked will die of the disease. Smokers also have a greater risk of an early death from cardiovascular disease, from emphysema and from other causes that could be indirectly related to tobacco smoking. There is no doubt that smoking is bad for you, and ‘the science’ can tell you quite a lot about why exactly it is bad for you.
The link between smoking and cancer is directly relevant to individuals, like me and you. If I smoke, there is a greater risk of my dying of lung cancer, and of my dying earlier that would be the case if I did not smoke at all. The risk is not absolute, but it is high, and a rational person would take it seriously. Governments are interested in the link, because smoking leads to expensive surgical interventions and hospital care that would otherwise not be necessary. We spend about 9 per cent of our GDP on health, broadly defined, and the proportion keeps rising, so governments everywhere are interested in reducing it.
Global warming or ‘climate change’ is a different kind of horse altogether. To begin with, it doesn’t matter at all what an individual does. Changing our light globes, riding a bicycle instead of driving a car, not flying — these decisions make no difference to the proportion of carbon dioxide that is in the atmosphere. We are simply insignificant as individuals in this domain.
So the first real difference is that in the case of smoking the effect is directly relevant to an individual, while in the case of ‘climate change’ the effect is said to be to the planet itself. It follows that the response to the threat of the effect of global warming has to be on a global scale. It now appears, however, that there is not much we can do about it. As former Commissioner Flannery came to admit, even if the whole of Australia followed the decision to cut greenhouse emissions by 2020 we would not as a nation make a discernible difference to carbon dioxide levels in the atmosphere. Even if the whole world followed our example, the change in CO2 levels would not be a great one.
The second difference is that in the case of smoking, while scientists are still unable to say why some people smoke and don’t die while others do, they can tell why smokers do die, when they do. In the case of ‘climate change’ or global warming, ‘the science’ is altogether more rudimentary. There is a well accepted view, based on radiative physics, that doubling the amount of carbon dioxide in the atmosphere will, other things being equal, increase global temperature by 1.1 degrees Celsius. Just about everything else is conjectural.
Other things are plainly not equal, if only because of the long pause in the rise of global temperature — and, as I argued the other day, if ‘natural’ factors can slow down the effect of radiative physics, it’s entirely possible that some of the warming that seemed to take place in the 1980s and 1990s was also due to ‘natural’ factors. In fact, we really don’t know a lot about how climate works, and it is a puzzle that the Australian Academy of Science and other such bodies continue to suggest that we do.
In short, any reasonably well-educated person can work out for herself that it is most unwise to develop a taste for cigarettes. Equally, she can work out for herself that our present knowledge about the earth’s climate does not require her to change her own lifestyle, let alone support her government’s requiring us all to do so, on the proposition that unless we do so humanity is doomed.