Yeah. These figures are completely irrelevant. The problem of increased CO2 concentration in the atmosphere isn't drowsiness, headaches and eventual suffocation, the problem is global warming. The figures seem to imply that once CO2 concentrations reach around 1000ppm we'll have a problem. But we have a huge problem right now.

The IPCC has been forecasting up to 1150 ppm by the year 2100, and they are a conservative forecaster (climate changes have been following their highest forecasts, or even higher).

So yes, your grandchildren may well live in a world where the freshest possible outdoor air is such that it makes humans feel sluggish and lethargic, like a stuffy indoor conference room today.