Yes, really, the red chart show the seasonal dips where plant grown reduced CO2 in the summer, but then in the winter the plants die, decompose, and return the CO2 to the sky. The seasonal plant cycle that is normal and natural is easily seen in the red. But the over all average, that you see in the black, obvious is NOT natural or normal. There is a constant artificial increase in CO2 that can only be explained by humans digging up and burning millions of years worth of concentrated plant material, in the form of oil, gas, and coal. There is nothing natural that would be dumping so much carbon into the atmosphere.
The problem is even more obvious if you look over a much longer period of time.
The increase in carbon is accelerating.
Nothing natural could do that.