How did you come to that conclusion?
Other than the fact that, assuming your figures are correct, the numbers above makes water vapor about 60-70X more ppm than CO2, not 10,000, you otherwise actually kinda make a pretty good point.CO2 is a greenhouse gas. So is water vapor. the concentration of CO2 is only 410 ppm. Water is around 20,000 to 30,000 ppm on the average. Or, around 10,000 times the concentration. What do scientists say about water vapor and cloud cover with regard to Climate Change? They tend to ignore it.
That too is also a pretty good point. Funny that the party of science always seems offended by anyone asking them any questions. But one should also realize that when CO2 was as high as you say it was long, long ago, it was not a climate very hospitable towards people nor would it be good for growing our food crops.Science, by definition, is inquiry. Always asking questions.