Computer model is not evidence

NZ Herald crest

Letter sent to the Herald on 7 Jan, 2011
quill pen

Dear Sir,

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. Continue Reading →