The "study" was a rigged compilation of papers by an agenda driven group conducted to prove a point of view that was determined prior to the start of the exercise.
"The abstracts from these papers were randomly distributed between a team of 24 volunteers recruited through the "myth-busting" website skepticalscience.com, who used set criteria to determine the level to which the abstracts endorsed that humans are the primary cause of global warming. Each abstract was analyzed by two independent, anonymous raters."
I defy you to find an article in the Skeptical Science Web site that gives full throated support to the idea that man has had no impact on the climate or that man cannot affect the climate.
This is an agenda driven site that has only one view point on this topic.