Don't plants like need co2? OH **** MANMADEGLOBALWARMING DEBUNKED!!! CONSPIRACY! AAAAAAAAAHHHHH...
it's the case of the straw breaking the camel's back, humans may produce what seems minimal compared to the natural environment, but co2 can only be absorbed to remove it from the atmosphere, what's almost funny is that we are actually in a period where the earth is absorbing more co2 then it is generating, but human contributions have put the total amount generated above the total amount absorbed, this in turn is causing co2 to just stay in the atmosphere, causing the green house effect, thus warming the earth, and the whole world starts getting a lot different just by changes in the atmosphere, it's what makes perfect (for humans) conditions for planets to be able to sustain life.
So even if co2 emissions were to be minimized (and we are a long way away from that), we would still need some sort of way to artificial absorb the co2 that is massing every year up in the atmosphere.
In a cruel but detached sense, the good part is that this is going to be a great method of population control over the next hundred years.
tl;dr natural emissions = ok, human emissions = ok, natural emissions + human emissions = not ok