Read the charts carefully. The left one represents greenhouse gases only. Greenhouse gases make up about 1 % of the atmosphere. Of this approximately 2% is manmade, i.e. 2/10000ths of the atmosphere is manmade and 99.98% of in is natural, and has also varied by more than the change man has caused. In other words, Earth has had many times more CO2 in its atmosphere, and yet life thrived.