A new brief summary of the reasoning and evidence behind the skeptics case. –Jo
The Skeptic’s Case Who Are You Going To Believe – The Government Climate Scientists Or The Data? Guest Post Dr David M.W. Evans
We check the main predictions of the climate models against the best and latest data. Fortunately the climate models got all their major predictions wrong. Why? Every serious skeptical scientist has been consistently saying essentially the same thing for over 20 years, yet most people have never heard the message — here it is, put simply enough for any lay reader willing to pay attention.
What the Government Climate Scientists Say
Figure 1: The climate models. If the CO2 level doubles (as it is on course to do by about 2070 to 2100), the climate models estimate the temperature increase due to that extra CO2 will be about 1.1°C × 3 = 3.3°C. 
The direct effect of CO2 is well-established physics, based on laboratory results, and known for over a century.
Feedbacks are due to the ways the Earth reacts to the direct warming effect of the CO2. The threefold amplification by feedbacks is based on the [...]