More than 3% of the carbon dioxide in the atmosphere is from humanity. At least net.
Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of PhysicsGlobal climatologists claim that the Earth's natural greenhouse effect keeps it 33°C warmer than it would be without trace gases in the atmosphere. 80 percent of this warming is attributed to water vapor and 20 percent to the 0.0385 volume percent of CO2. If CO2 exhibited such an extreme effect, however, this would show up as a thermal conductivity anomaly even in an elementary laboratory experiment. Carbon dioxide would manifest itself as a new kind of 'super-insulation,' wildly violating the conventional heat-conductivity equation.