Plants are not a "sink" with a static limited capacity. They are a dynamic variable and simply keep growing. Or perhaps you hadn't noticed.
The problem with ALL people who have bought into the various liberal claptrap is that they are completely unable to grasp the cause and effect and reaction idea. For example, when taxes are lowered significantly, liberals invariably wail about lost revenue and "how are we going to pay for this" when the TRUE effect is that revenues go UP as people are encouraged th earn and spend more of their own money.