He says fundamental flaws in how future temperatures may rise have been included in the 'standard models' and this has led to inflated mathematical - and therefore temperature - predictions.
Googling finds a number of other sites with the same story. Some identify Dr. Evans as a "former climate modeler for the Australian Greenhouse Office", others as an electrical engineer. None seem to provide any skepticism about Dr. Evans' statements.
I'm sure this is a sham, as otherwise it would be an enormously important story that would be reported everywhere. If so, I'm a little surprised that I found no "boy is this stupid" responses. Perhaps the real climate experts are tired of playing "climate conspiracy Whack-A-Mole".
If a climate change denier were to use this story as proof that anthropogenic global warming is a scam to keep earth scientists employed, what would be the best way to show that he is wrong?
Edit: I just found that Dr. Evans serves on the Board of Advisors of the Committee for a Constructive Tomorrow, an NGO that denies man-made global warming exists.