Observed changes in atmospheric CO₂ concentration during the instrumental period andisotopic signatures back to the Little Ice Age are likely explained by natural biogeochem-ical feedbacks, with no detectable anthropogenic contribution.
We know that, "uptake of atmospheric CO2 should react not to a change in emissions, but to a change in concentrations" (Knorr 2009). So if our current anthropogenic emissions of 4.9 ±0.5 ppmv/yr of fossil CO2 were to suddenly cease, the CO2 trend would be reduced by that same amount: 4.9 ±0.5 ppmv/yr. That means it would be negative instead of positive: initially averaging about -2.4 ±0.6 ppmv/year instead of the current average of +2.5 ±0.1 ppmv/year.
In other words, were it not for ongoing anthropogenic CO2 emissions the atmospheric CO2 concentration would currently be falling, rather than rising.
That obviously means that the current upward trend in atmospheric CO2 concentration is entirely due to anthropogenic emissions.
● Mankind is ADDING CO2 to the atmosphere
● Nature (the net sum of all non-anthropogenic carbon fluxes) is REMOVING CO2 from the atmosphere
● The atmospheric CO2 level is currently rising because mankind is currently adding CO2 faster than nature is removing it.