I am suspicious that anyone has actually read hundreds of papers in this field.
First, global warming could be and probably has been happening for some period of time before now. The debate is over whether or not man is the cause of any or all of it. From what I have read, there was the little ice age so we are warming out of that. Perfectly natural as the temp of the earth has varied over time.
Some of the papers (like the hockey stick graph) were discredited as sloppy science. Maybe it was intentional. I do not know. I know scientists in other fields who have had papers published and there were errors in the stats.
I think the emails from East Anglia and Penn State folks seriously tarnished the image. When you have one of the leading scientists in the field boasting about changing the rules and that papers that have contrary points will never be published, then you have a real problem.
Also, in the scientific world of published papers, the raw data and methodology are supposed to be made available. The climate folks have not been responsive to such requests. Again the East Anglia folks emails shine an unkind light on that process (they would rather destroy the data than turn it over or would fight to keep it locked away).
I think it is less of conspiracy (although some of the emails do give that impression) than scientists looking to either get grants (one gets no grants if there is not a "problem") or scientists with bias.
On another side, Bjorn Lomborg (who believes in man-made global warming) thinks that the cost is too high for the fixes being proposed when you look at the cost and how many lives would be saved. He argues that if you are concerned about saving lives then there are cheaper and proven things you can do (clean drinking water, sewage, mosquito nets, using DDT again).
There is a faction of the Global warming (climate change is the proper term since it covers all the bases) that just wants government control and does not care much for freedom or capitalism. Not everyone is a watermelon (green on the outside, red--as in Commie---on the inside) but quite a few are.
There are far better conspiracy theories to have fun with and that also do not endanger our freedoms.