History In 800,000 Year Old Air Bubble

Air bubbles trapped in Ice Cores taken from Antarctica give us a lot of information and as they go back over 800,000 years, that is a lot of information but scientists have been using it to date major Global events, or rather for the previous 799, 800 years because they measure Carbon Dioxide and it all gets rather hazy after the late 18th Cetury because us humans began pumping the stuff out.
'As the snow was falling, it also trapped pockets of air' says Amy King, a research scientist for the British Antarctic Survey and by drilling into the ice, scientists can extract a long cylinder of ice and analyze the air and gasses from the past as a sample sample of the atmosphere as it was at that time.
The air trapped in the ice reveals information about things like droughts and volcanic eruptions charts the progress of human industry as traces of metals such as copper and lead begin to appear from mining and smelting operations as well as for our large scale use of leaded petrol as well as the rising and decline of CO2.
King explains that the amount of carbon dioxide in the atmosphere is a balance between the things that emit carbon dioxide and things that absorb carbon dioxide such as forests so when there is a massive reduction in human population, there is less CO2 as the forests grow back over land which was previously agricultural land and more CO2 was absorbed by those plants, thus reducing carbon dioxide levels across the world and this is recorded in the ice bubbles.
Around 70,000 years ago, humanity's global population dropped down to only a few thousand individuals due to a massive supervolcano plunging earth into an ice age and pandemics such as the Black Death which killed between 40% and 50% percent of the entire population of Europe and these are recorded in the ice cores.  
While events once had the ability to alter Earth’s atmosphere, due to there being a much larger background emissions of carbon dioxide today compared to the previous 800,000 years as for the previous 799,800 years the concentration of atmospheric CO2 naturally was between 180-280ppm and but since approximately 1850 it has been rising steadily and today it stands at 410ppm meaning we have managed to do in under 200 years what nature couldn't do in 800,000 which puts a massive hole in the numbskull argument that rapid Climate Change and rising CO2 is a natural occurrence that has been going on for tens of thousands of years.