This nifty little website (Global Warming?! NOT!) with a super catchy title has some fun with numbers.
Average daily C02 exhaled by the world? 3.3 billion lbs. Average "exhalation" from cars? 9.5 billion lbs CO2. The page also touches on equilibrium:
A decrease in underwater volcanic activity causes more carbonate residue to form on the ocean floor.
As the carbonate residue continues to precipitate out, the oceanic carbon dioxide levels drop, and less carbon dioxide is released back into the atmosphere.
As the atmospheric carbon dioxide levels drop, less carbon dioxide is depleted by the rain.
As the rain dumps less carbon dioxide into the ocean, oceanic carbon dioxide levels drop, causing less precipitation of carbonate residue.
Algea growth diminishes somewhat due to reduced carbon dioxide levels, producing less oxygen.
Similarly, plant growth on the earth's surface is reduced slightly, producing less oxygen.
A shift in worldwide oxygen production causes an effective increase in carbon dioxide levels in the ocean from animal respiration, and to some extent, in the atmosphere.
A new equilibrium level is reached where carbon dioxide levels in the atmosphere may be immeasureably lower than they were before, but not significant enough to cause global warming/cooling. Carbon dioxide levels in the ocean are measurably lower, but total dissolved gas concentrations remain roughly the same.
Oceanic animals breathing the slightly higher concentrations of oxygen flourish a bit more than usual, causing an increase in the production of CO2. A new "biological equilibrium" is reached in the oceans.