A few weeks ago Stephen Lewandowsky, James Risbey and Naomi Oreskes posted at the Conversation “Climate change is not all disaster and uncertainty“. This compared the strongly-supported hypothesis that “Smoking causes lung cancer” with the hypothesis that “climate change will cause extreme weather events”. Below is the comment I posted.

You make an analogy between climate change and smoking causes lung cancer. It is worth exploring this analogy further. According to Cancer Research UK 86% of people who caught lung cancer in 2010 were smokers. A smoker is 15 times more likely to catch lung cancer than somebody who has never smoked. Put another way, only 1 in 15 smokers who caught lung cancer would have caught it anyway – and you cannot identify which these people are. Also lung cancer has a 90% mortality rate and can be diagnosed by professionals very clearly. It is a nontrivial problem both for the people experiencing it and there are large numbers dying from it.

http://www.cancerresearchuk.org/cancer-info/cancerstats/types/lung/riskfactors/

Climate policy is about prevention of nontrivial adverse climate change, predicted to happen many years into the future. With less than one degree of warming so far (which might be partly natural), the severe effects are difficult to detect amongst all the infrequent naturally-caused extreme events, with natural cycles and fluctuations. There are two ways that this differs from lung cancer.

Firstly, somebody either has lung cancer or not. There is no trivial in between. In between human caused climate change being false and there being an apocalyptic problem, there is a huge range of possibilities. This is from the highly trivial through being a significant problem, to being serious enough to justify global mitigation policy.

Secondly, whereas for a smoker who catches lung cancer it is most probably caused by smoking, an extreme weather event occurring now will most probably not be caused by climate change, whereas (if the predictions are correct and no successful policies are implemented) one happening in 2100 will most probably will be.

That leads to a dual problem. Extreme weather events may become much more extreme in the future, but this will only be detectable over large numbers of similar events at the present time. Even that will not necessarily point to a problem severe enough to justify the adoption of mitigation policies.

If there is false attribution or exaggeration for promotion people will smell something quite different than the climate science. There has been huge damage to climate change cause in England from the prediction in 2000 that children will grow up never knowing what snow is, or in the USA by saying hurricanes would become more frequent and stronger after Katrina. As a result of these and other failures many people will fail to believe anything that is said by competent scientists. Unless more objective and scientific methods are discerned for isolating the anthropogenic climate change signal than the hollering of climate activists, then the message will not get across. Even for those not turned off, the failure of the short-term predictions will conclude (like most sceptics) that it is a far more trivial problem to that which the climate consensus portrays.

Kevin Marshall