In past millennia, volcanoes, earthquakes, and fluctuations in the sun's radiation have sometimes caused earth cooling, and sometimes caused earth warming. With all these fluctuations, increases and decreases in CO2 ppm in the atmosphere, sometimes occurred when the earth cooled and sometimes occurred when the earth warmed. Consequently, historically there is no real correlation between the occurrence of CO2 ppm changes in the atmosphere and changes in the earth's average temperature.
Yes, CO2 ppm increases in the atmosphere over the last 100 years do coincide with increases in the earth's average temperature. But the increase in the earth's average temperature is far more likely caused by the occurrence of volcanoes, earthquakes, and increases in the sun's radiations to the earth over the same period, than it is caused by increases in human produced CO2.
Also coincidentally, the number of democracies around the earth has increased dramatically over the last 100 years. Why not blame that--or any other increase over the same 100 years--for causing earth warming over the same period?