If you believe they are wrong, go tell the government. That's the source for the 14% number that I previously linked on the thread.
Carbon Dioxide Information Analysis Center
That's the key phrase and the key words. (ALL of the additional CO2 went into the atmosphere; 40% of it is still there.) Were it not for human activities, atmospheric CO2 concentrations would not be increasing. Because of human activities, atmospheric CO2 concentrations are increasing. The CO2 that goes into the atmosphere mixes with the CO2 already in the atmosphere, so what gets removed by natural processes (sinks) is a mixture of natural and anthropogenic CO2 (starting about 1750 or so, natcherally). Nature doesn't discriminate, it's all CO2.
So go back to the bathtub analogy and think it about it. The increased addition of the water to the tub, cup by cup, would be the complete and utter and total and only cause of the rise. But it gets mixed in the tub. So what goes out the drain is a mix of what goes in the tub from the faucet and what goes into the tub from the cups of water you're adding.
It's really actually very simple. I'm totally right. So is the government.