Hundreds of scientists urge Trump to..., page-29

So let me get this straight, those dips in this chart below which show the northern hemisphere sequestration of CO2 that exceeds the new production of CO2 would have no bearing whatsoever on atmospheric CO2 if humanity stopped producing any CO2 ? Is that correct?

The way I see it, if we stopped producing CO2 the concentration would fall quite a bit, especially in the first year when one considers that despite the output of CO2 during the NH summer it(the concentration of CO2) falls in the NH summer