Some scientists claim that anthropogenic (human-produced) CO2 (carbon dioxide) lasts in the atmosphere for hundreds or even thousands of years. Of course, they also think that CO2 is the mother of all evils and, therefore, argue that the world needs to decarbonize, forget about using fossil resources (coal, oil, gas), and reduce the population from seven billion to one billion humans.
Well, if that's so, the world must be suffering from CO2 exhalations by the ancient Sumerians, Egyptians, Romans, and everyone else who lived since that time.