You said ----the world would be lush and green at 1000 ppm CO2.
That suggests by increasing CO2 levels it has only positive benefits for plants.
However at that level of CO2 many parts of the earth will be too hot for plants to thrive.
Many parts of the earth will be too wet for plants to thrive.
Many parts of earth will be under sea water or the water table will be polluted with salt.
Plants need oxygen around their roots as at night there is no photosynthesis and roots need oxygen 24 hours a day- a reason to avoid planting in waterlogged areas.
Plants can grow without soil as any dope grower will tell you but this conversation is about your statement that CO2 increases will automatically cause 95% of the earth to green.
It will help for a while but a point will be reached and well before 1000ppm that CO2 will kill or damage most plants on earth and as a result there will be mass extinctions of animals.
CC deniers find these sorts of warnings difficult to accept but Mother Nature doesn't discriminate.
