Climate change is a far more serious, rapidly acting and widespread problem than any previous threats that our species has had to face in the last 12,000 years. 

Many previous environmental and health problems have indeed turned out not to follow the worst-case scenarios predicted by some 20th century experts e.g. the pesticide DDT, BSE (bovine spongiform encephalitis), Salmonella in eggs and the millennium computer bug. Nearly all these scares have prompted responses, such as national legislation, to reduce their risk. However, there have been few controlled experiments where we could compare how bad some of these problems might have been if there hadn’t been the appropriate government action in response to the scientific data and public concern.

Climate change as a problem is far more serious than any of these previous concerns because it is global, it is in train now, a lot of evidence suggests it is getting worse and it has potential impacts that would be worse than nearly all previous threats (perhaps with the exception of the total destruction that would follow from a full-scale nuclear war). Climate change might turn out to be not as serious as the most pessimistic climate scientists are currently predicting, but we shouldn’t rely on this – the risks of doing so are too high. The precautionary principle should apply. Just because some people, sometimes with a strong vested interest in the status quo, are tempted to downplay the dangers and use special pleading, it makes little sense to deduce that the climate change problem isn’t important. It is worthwhile contemplating the motivation of those who promote such thinking, provide false comfort and potentially delay action at a moment when time is running out for a relatively smooth transition to a very different low-carbon world.