Had to be a LOT of CO2 in the air to support the amount of plant life needed to support such a giant creature....
I know what caused the extinction of the dinosaurs, it was the liberal and gaia worshiping dinos that forced everyone to cut their C02 emissions and they destroyed their food source.
It's a real shame too. Once Dick Cheney's Haliburton started selling oil for cars global warming kicked in, and of course that's what killed off all the dinosaurs.
There didn’t need to be any more CO2 then than now to support dinos’ food supply. The problem is, dinos need a lot of oxygen to support respiration — when the Chicxulub impact happened, oxygen levels fell, the food supply vanished, and the surface of the Earth lost sunlight for years, probably decades.