Regulating Plant Food?

In a hearing last week about regulating carbon, Rep. John Shimkus (R-IL) remarkably questioned the need to regulate carbon, saying that carbon is just plant food and we'd do more harm than good.

SHIMKUS: It’s plant food … So if we decrease the use of carbon dioxide, are we not taking away plant food from the atmosphere? … So all our good intentions could be for naught. In fact, we could be doing just the opposite of what the people who want to save the world are saying.