Bull....I've seen no really credible estimate that pegs man's contribution to the total planetary output of CO2 at any number above 6%....
This source is about as mainstream as they come.
Yet again, the scaremongering Malthusian dog don't hunt.
Dumb ol' Dooodeee....... You haven't seen the real numbers because you have not looked for them.
How do human CO2 emissions compare to natural CO2 emissions?
About 40% of human CO2 emissions are being absorbed, mostly by vegetation and the oceans. The rest remains in the atmosphere. As a consequence, atmospheric CO2 is at its highest level in 15 to 20 million years (Tripati 2009). A natural change of 100ppm normally takes 5,000 to 20.000 years. The recent increase of 100ppm has taken just 120 years.
Additional confirmation that rising CO2 levels are due to human activity comes from examining the ratio of carbon isotopes (eg ? carbon atoms with differing numbers of neutrons) found in the atmosphere. Carbon 12 has 6 neutrons, carbon 13 has 7 neutrons. Plants have a lower C13/C12 ratio than in the atmosphere. If rising atmospheric CO2 comes fossil fuels, the C13/C12 should be falling. Indeed this is what is occurring (Ghosh 2003). The C13/C12 ratio correlates with the trend in global emissions.
100 ppm out of 387 ppm is a lot more than 6%.