CO2 when dinosaurs roamed the Earth. I answered. That answer did not come from the OP.
But the article in the OP does have merit. We havent seen CO2 concentrations like this in a very long time.
And while we can say "No Worries! Its cyclical..." Its really not.
https://climate.nasa.gov/climate_resources/24/graphic-the-relentless-rise-of-carbon-dioxide/