Imagine sitting in a bar and discovering you’ve lost £145. Now imagine the guy sitting next to you shouting for joy because he’s found £145 on the floor. Wouldn’t you assume it was your money?
In the same way, the amount of carbon that human activities have “lost” by pumping carbon dioxide into the atmosphere matches closely the extra carbon now “found” in the air, ocean, soils and plants.
It could be a coincidence, but that would mean some magical, unspecified process has removed all the human emissions whilst, at the same time, another magical, unspecified, process has added back exactly the same amount. It’s just not credible!
Data showing the carbon balance between human emissions and environmental take-up can be found at https://globalcarbonbudget.org/.