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.