Congratulations. This question is worthy of a skeptic, rather than the others, which have simply been denial.
Pielke Sr. is a retired meteorologist who believes that regional conditions deserve more emphasis than they've been getting. He also believes that, while man is significantly affecting the climate, changes in things like land use are somewhat more important, and man made CO2 somewhat less important, than most scientists.
The bottom line is that he quantitatively disagrees about some of the specifics of global warming, but is not "skeptical" about the concept that man is significantly affecting the climate in an adverse way. He has, in fact, vehemently objected to the term "skeptic" being applied to him.
Here are some of his views from his own website:
"Humans are significantly altering the global climate, but in a variety of diverse ways beyond the radiative effect of carbon dioxide. The IPCC assessments have been too conservative in recognizing the importance of these human climate forcings as they alter regional and global climate." Not exactly a ringing criticism of mainstream thinking.
http://climatesci.colorado.edu/category/climate-change-forcings-and-feedbacks/
His scientific views are worthy of consideration. Complaints about the IPCC - not so much. Those are more idiosyncratic. Membership in the IPCC is not limited to those who accept the mainstream view. However, "skeptics" tend to quit. IPCC works by consensus, which is not the same as unanimity. The views of the skeptics are routinely outvoted by margins of 100:1 or more (similar to the actual division in the scientific world), and so don't make it into the final report. The IPCC report simply reflects the judgment of the scientific community. Including the skeptics views would be like including creationism on a scientific treatise about evolution.
Anyway, Pielke Sr. is worth reading, even if his is a view held by a small minority. He argues using data, rather than simple opinion.
Welcome to the serious discussion.