Complaint to Ofcom Regarding “The Great Global Warming Swindle”

The documentary is committing a logical fallacy (false dilemma) by suggesting that because rising temperatures have caused CO₂ concentrations to rise in the past, therefore CO₂ concentrations could never cause temperatures to rise. This is analogous to the saying that because increasing the number of fertilised eggs in a chicken coop will eventually lead to an increase in the number of chickens, that proves that increasing the number of chickens in a chicken coop could not possibly lead to an eventual increase in the number of eggs. It works both ways – when temperatures rise, atmospheric CO₂ levels rise (but this happens slowly, over hundreds of years); and when CO₂ levels rise, this results in temperatures rising (but this happens much more quickly, over a few decades).

The programme’s suggestion that the theory of the greenhouse effect somehow depends on the ice core data is also extremely disingenuous and misleading. The theory of the greenhouse effect is well-established physics that dates back 150 years. It is covered in the most elementary text books on climate physics. The ice core data is not – as the film maker pretends that it is – important evidence supporting the theory, still less is it “the most fundamental assumption” behind the theory. However, the ice core data does reinforce the theory, because in the absence of the greenhouse effect it would be more difficult to fully account for amplitude of temperature changes inferred from ice core data, for the reasons described above.

Atmospheric CO₂ levels don’t spontaneously increase for no reason; rises have to be triggered by something. In the past they were triggered by rising temperatures, now they are being caused by human CO₂ emissions. In the absence of human emissions, as during recent deglaciations, rises of atmospheric CO₂ were likely triggered by rising temperature. Hence it is not surprising that in the past, temperature rises started before the atmospheric CO₂ level began to rise. But those CO₂ rises then greatly increased the temperature.