what percentage of co2 in the atmosphere is natural

Carbon dioxide occurs naturally in small amounts in the Earths atmosphere, about 0.04 percent. However, the concentration of carbon dioxide in the atmosphere has increased significantly since the beginning of the Industrial Age, when the concentration was near 280 ppm, and it is currently at nearly 412 ppm. Human activities, such as the burning of fossil fuels, are responsible for the majority of the increase in carbon dioxide concentration in the atmosphere. Therefore, it can be inferred that the percentage of natural carbon dioxide in the atmosphere is around 0.04 percent.