What is a full range? does that have a number, is it a million kg per year? 5 million? And how does that compare to the actual atmosphere composition given that the atmosphere forms a 300 mile thick radius around the entire planet. Is the amount of greenhouse gases released by humans enough to make a dent in something large enough to form a 300 mile thick layer around the planet? Lets face it - you and climate science doesn't have the answers to these questions and until it does it will remain a hypothesis.
The six gases in the atmosphere that appear above 60 ppm have a combined mass of about 14.85 g/mol. Removing 100 ppm of CO₂ would reduce the mass of the atmosphere by 1.23 g/mol, or 8%. To convert that to kg/year, we have to take 8% of the mass of the atmosphere, roughly 5.14E18 kg, and divide by 100 years.
So a range is 4 thousand million million kg per year, or 4000 short scale gigatons per year, and is absolutely able to make a bulge in the atmosphere.
edit: I re-calculated the mass of the atmosphere. assuming that CO₂=C+O₂. This time I got 14.3790 g/mol, where replacing 100 PPM of CO₂ with O₂ reduces the mass by 0.0012 g/mol or 0.008%. That would correspond to 4 gigatons per year, whereas current estimates are 40 gigatons per year.
Now, I don't know much about climate change either, so I googled it. The IPCC 2007 report outlined how the last 20,000 years of glacial record show a warm period very similar to the four warm periods in the 600,000 years prior. However, the CO₂, CH₄, and N₂O levels in the last 250 years have continued to rise beyond the normal peak, currently exceeding previous records by over a full range. So it's evident that something has been releasing unprecedented levels of greenhouse gases in the remarkably short time since the industrial revolution.
As for CO₂ in particular, it's merely the most direct byproduct of burning wood, coal, and oil. It's not the strongest greenhouse gas, it is the simplest causal link between the massive sustained burning of carbon and vast quantities of CO₂ spontaneously appearing. If you want to know more about how CO₂ is a greenhouse gas, I'll be happy to google that, too.