Man has almost certainly warmed the world by some tenths of a degree C with his CO2, though much of this warming has hit night-time lows rather than daily highs. Anyway, while future temperature rise forecasts are often grossly exaggerated by absurdly high assumptions of positive feedback, there is at least a kernel of fact in there that CO2 is likely warming the world somewhat.
However, the popular "science" on climate change is often awful, positing, for example, that hurricanes are being increased by man right in the midst of the longest hurricane drought we have seen in the US for a hundred years.
Inevitably, the recent severe California droughts have been blamed on manmade CO2. As a hopefully useful adjunct to this debate, I have annotated a recent chart from the San Jose Mercury News on the history of California droughts to reflect the popular global warming / climate change narrative. You be the judge of the reasonableness: