I see why you posted as AC, because your argument sucks. The carbon cycle is a balance, and increasing atmospheric CO2 throws it off terribly. Plants and vegetation are less than 50% of the carbon sinks, the ocean actually takes up more CO2 than plants. CO2 interacts with calcium and is stored in the ocean, however, this reduces the pH (which is slightly basic, now). When the ocean starts to become acidic, this mechanism will shut off, and the ocean will no longer be a sink of CO2, so not only will CO2 concentrations continue to rise, the yearly increase will shoot way up.