To be honest, there are studies showing that levels of CO2 has risen over the past 1000 years. A sharp rise is seen in the rightmost part of the graph, suggesting that CO2 has risen significantly after the industrial revolution. graph from intergovernmental panel of climate change.
Also this graph from the National Energy Information Center (NEIC) shows an increase in CO2:
The average mass of the atmosphere is about 5000 trillion metric tons.
Therefore, the only thing your chart proves is that 380-280=100.
Yes we know CO2 OFTEN goes up and down with temperature but not always.