Letter sent to the Herald on 7 Jan, 2011
It has come to my attention that you published a (further) letter from a Dr Doug Campbell, again challenging Professor Chris de Freitas’ recent article about the science of global warming. Dr Campbell said: “The facts support anthropogenic global warming with a doubling of atmospheric carbon dioxide resulting in warming of between 2 °C and 4.5 °C.”
I wish to point out that, as a matter of fact, that is not a fact.
Dr de Freitas was talking about an expected temperature increase from carbon dioxide alone of about 1 °C, and he mentioned that was, “by itself, relatively small” and “not controversial.”
Dr Campbell, if he disagrees with that, should cite his authority for doing so. The only source of temperature increases greater than one degree is various computer climate models. These models give different results on each run.
It is vital to recognise that the model results are not “facts” or “evidence”, nor should they be in the least persuasive of future climatic conditions. The IPCC themselves forbid the use of terms like “forecast” or “prediction”, in favour of “scenario”, “projection” or, more tellingly, “storyline”. The IPCC definitions are set out here.
Dr Campbell overlooked the fact that Dr de Freitas carefully described the carbon dioxide-induced temperature rise separately from any increase that might follow (called feedback). Because the only source of a temperature increase from feedback is these untested models (which, by definition, make no predictions), it is controversial. Thus it is improper for Dr Campbell to present those “storylines” as a scientifically reasonable “result” by using the words “the facts support”.
Research is under way now by Roy Spencer and others to discover the reality, and the indications are that there is a significant negative feedback from increased cloud formation in the tropics. Research is still under way because results are inconclusive.
But for Dr Campbell to drive his bulldozer of illogic through those scientific results without offering opposing observations is the antithesis of science.
Climate Conversation Group
PS: To CCG readers – please let me know if you see this has been published. Thanks.