1) Many people already live in high-CO2 indoor environments. Please see my earlier comment elsewhere in this thread where I relate how my own home quickly shoots up to over 1300 ppm if I turn off my ventilation system. Most people don’t even have ventilation systems.
2) People should monitor their indoor air quality. Consider giving a CO2 monitor to friends and family who don’t have one.
3) We can draw no conclusions from this paper. Please see my earlier comment that the statistical analysis is flawed and the methods could have been better.
4) There is a serious problem with the motivations, execution, dissemination, and interpretation of research today. This has been a problem for as long as scientific papers have existed. Einstein once told Norbert Weiner that he deplored the flooding of the literature by immature, idea-less papers. I don’t think the situation has improved since then. Recent politics haven’t helped.
5) Animals, even mice, should never be harmed without strong justification.
Here’s where we disagree:
1) The fact that people already live in high-CO2 environments does not imply there are no ill effects. There have been multiple studies indicating that high CO2 environments significantly degrade cognitive performance by large amounts. This implies some plausibility for developmental effects in children, which we have seen with other pollutants.
2) Although your outdoor CO2 measurements are not individually unusual, you should generally see an average below 500 ppm unless you live near an unusual outdoor source of CO2. Even next to a busy road in a highly polluted city, the average should be below 600 ppm. I suspect there is either an issue with your monitor or your breath may be sometimes drifting to the sensor. Your own breath can cause errors of several hundred ppm. Be sure to keep the sensor at arm’s length and stay downwind. Even better, get a unit that will record a history and step away from it for awhile.
3) You imply the paper makes extreme claims that it does not actually make. You are probably right that others will make extreme conclusions, but that is different.
4) A study does not need to reach a valid conclusion to have value. Much of science requires eliminating dead ends and finding potential hypothesis for follow-up. It is not economically feasible to study all possible hypothesis. We must make some advancements through incremental trial and error. This paper serves an exploratory function. The methods are reasonable enough to propose hypotheses for a couple of developmental effects. This was really more of a pilot study, although I doubt that was the intent. I’ve seen worse pilot studies that were still useful. To reach credible conclusions, other studies would need to be performed using a larger number of subjects and/or fewer tests along with better statistical analysis.
5) For the past 10,000 years, outdoor CO2 levels averaged around 280 ppm. Tripling that over a few hundred years is an extreme event. It is vital that we understand the potential consequences as soon as possible. I believe mitigations are possible if we develop sufficient motivation.