Here is a depiction of CO2 levels over the last 800,000 years, also showing current and projected levels over the coming century or so:
Another Nail In The Coffin
Of course, one needs to look at this in the context of how long human civilisation has been around:
So, CO2 levels are higher than at any time since organised human civilisation started to develop. Physics tells us that increased CO2 = increased temperatures. Are you starting to see the problem?