World Atmospheric CO2, Its 14C Specific Activity, Non-fossil Component, Anthropogenic Fossil Component, and Emissions (1750–2018)

Our results show that the percentage of the total CO2 due to the use of fossil fuels from 1750 to 2018 increased from 0% in 1750 to 12% in 2018, much too low to be the cause of global warming.

https://journals.lww.com/health-physics/Abstract/2022/02000/World_Atmospheric_CO2,_Its_14C_Specific_Activity,.2.aspx